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HOUSE PAINT ON MY AIRPLANE?
By: Charles Threewit
Published: July, 2002 Custom Planes Magazine®

Today’s modern latex paints are miracles of chemistry.

Someone queried the members of the EAA on their web site about using latex paint on aircraft, and the responses were interesting. Some people had used it. One gentleman said he was 72 years old and had been in aviation for 55 years. He thought these facts gave the knowledge to predict dire results from its use.

His attitude, and that of the other nay Sayers, reminds me of when the Wright brothers’ father, a few days before their historic escapade at Kill Devil Hills, emphatically said to the press that “If God had wanted men to fly, he’d have given them feathers!” Or it’s similar to the sagacity of the long-departed IBM CEO, who said, in the late 1970s that “As near as I can calculate, there will be a worldwide market for a total of about five home computers.”

Actually, the following are several good reasons to give serious consideration to the use of latex paint on fabric-covered aircraft:

*A low cost of about $20 a gallon, compared to several hundred dollars per gallon for more exotic paints
*Ease of application and total lack of toxicity
*Its tenacious hold on fabric fibers
*Its flexibility
*Its resistance to UV damage
*An infinite variety of colors
*The dealer’s ability of computer-match paint samples

Years ago, model aircraft builders who had an aversion to the cost of automotive-type paints discovered the usefulness of latex paint on aircraft. And, in many cases, they didn’t have the equipment or the knowledge for proper application of these exotic materials. In addition, automotive paints require expensive breathing apparatuses; in curing they give off cyanide and they’re extremely unfriendly to the environment. Many award-winning giant-scale model aircraft are finished with latex paint today, and there are several web sites devoted to the subject.

Note: To be called “giant-scale,” a model has to be at least ¼ scale or have a wingspan of al least 80 inches for a single wing or 6o inches for a biplane.

One excellent article on painting and detailing giant-scale models can be found at http://www.modelairplanenews.com/how_to/latex.asp. The author, a nationally known, award-winning modeler, has used latex to finish his planes since 1983. He had been using expensive epoxy paint, but he couldn’t match the colors on a plane he had repaired after a crash. He went to the local Benjamin Moore dealer for help and learned they could match the colors exactly-for about 1/8 the cost–by using a computerized spectrometer. After refinishing the model with Benjamin Moore latex applied over conventional automotive primer, he was surprised to discover that the newly repaired plane was now 4.5 pounds lighter than the original had been-even with all the extra material used for the repairs.

It’s interesting that the SR-71 Blackbirds on display at the Blackbird Airpark in Palmdale, California, were painted with black latex to protect them from the vicious UV content of the high-desert sun. During flight, the plane’s skin temperature approached 575 degrees F, so latex obviously wouldn’t be suitable for flight. But, it works great to protect the grounded birds from the ravages of the desert sun.

 

The picture (above) shows all the equipment required for a basic paint job using latex paint. In the center is the paint; I used a can of bright red I had sitting on my shelf. To the right of the paint are a foam roller, a couple of foam brushes and a good-quality bristle brush. To the left of the paint is a product called Floetrol. It lowers the viscosity and surface tension of the paint and helps it to spread more easily, making for thinner coats and easier application.

The jug on the far left contains windshield-washer solvent. It’s an excellent thinner for latex paint, although the paint folks won’t recommend it (they recommend no thinning or thinning with water only). Latex paint contains ammonia and so does windshield-washer solvent. The solvent also contains small quantities of detergent, which also contributes to ease of spreading. Small brush marks left in the paint quickly even out while the paint is still wet and small marks continue to disappear over the next several days. And cleanup is with water, as long as the paint is still damp. Like any other paint, it resists solvents after it dries. After all, that’s what it’s for, isn’t it? By the way, latex is impervious to gasoline after it sets.

Latex is also easy to spray, although most folks recommend brushing on the first coat to control the application of the paint to the raw covering material, which should be cleaned with MEK to remove any grease, oil or residue from adhesives. Care must be taken in this step; obviously, because MEK is the solvent used in the adhesives, and we certainly don’t want to loosen the covering after it’s applied and stretched.

Just as in the application of sealers and primers, care must be taken not to apply such a heavy layer of paint that puddles begin to form on the backside of the cloth. That’s the reason for the recommendation to brush the first coat, which allows much better control for those of us who aren’t expert spray painters.

Latex doesn’t form a chemical bond with the fibers of the covering, but it forms a tenacious mechanical bond as it wraps around them. Succeeding coats then form an excellent bond to the preceding coats, especially if the last coat has been scuff-sanded. Note that latex paint doesn’t like being wet-sanded. Even when it’s well cured if it’s kept wet for any length of time, it’ll begin to roll up under the sandpaper. When it must be feathered it must be done with care, patience and practice.

When spraying my models, I use either an automotive-type touch-up spray gun or an airbrush. I’ve used my quart-size gun to spray my house with latex, and it works just as well with latex as the others. I have a 2-hp compressor I use with the larger guns, and I’ve always used my small diaphragm-type compressor with the airbrush, although there’s no reason not to use the larger compressor with it. It’s essential that the compressor is equipped with water and oil trap, any minute quantity of oil in the paint will cause it to fisheye. This will necessitate removing the paint. Fortunately, any goofs we make can be immediately corrected while the paint is still wet. Just use a wet rag to wipe it off.

Roy Vaillancourt’s Web site has an excellent discussion about the way he prepares his paint for spraying. He also writes about the application of the paint. For him, it’s usually on fiber glassed and primed surfaces, but the principle is the same. Start with a very light coat, and after drying; add two more coats, with the second being allowed to dry before adding the third. Because the solvent in latex is water, the paint dries rapidly, depending on the temperature and humidity. Vaillancourt uses a heat gun to dry the paint on his models.

One of the neat things about latex paint is its opacity. The old rule about never putting light colors on top of dark doesn’t apply with latex. Although it’s still a good idea to use dark over light, it isn’t a necessity with latex. One manufacturer advertised that its paint contains 48% solids, by weight, far higher than anything else I’ve seen, other than polyurethane, perhaps. This certainly accounts for the high opacity of the paint.

Some folks who use latex on full-scale planes use a base coat of black paint for ultraviolet protection. However, if the bare fabric is going to be visible in the finished plane, the black color isn’t too desirable. An interesting Web site (http://www.larryvile.com/dcd/tandem/latex1.htm) describes the painting of a Ragwing Ultra-Piet (a ¾-scale Pietenpol Aircamper). The author didn’t use an undercoat of black on his Ragwing because he didn’t want the black to show in the cockpit. Also, he says he was concerned about the weight-saving possibilities. He said, “If I was still flying the airplane in 10 years, it would probably be ready for new fabric anyway, I figured, UV degradation or no.”

Then he describes how he devised what he calls “an accelerated aging test, something much harsher than it would see on a hangared airplane.” He prepared a sample of fabric, stretched on a wood frame, and applied single coats of red and white latex to various parts of it. Then he placed the sample outside, learning against the south wall of his shop. He left it there for the next 6-1/2 years. Believe me the south wall, in Lawrence, Kansas, does get a lot of sunshine!

He tested the sample periodically for deterioration of the fabric, and only at the end of the 61/2 years was he able to detect any UV deterioration. He makes no claim for the scientific accuracy of his field test, but he says it satisfied him to know that his plane could be safely flown without a black base coat. More than one coat of paint would greatly increase the opacity of the paint and serve even further to prevent UV damage.

There’s some humor included in the description of the test. One of the lower corners of the test sample, painted white, is severely discolored. Aha! Have we finally found a weakness in latex paint? Does it turn yellow when exposed to sunlight? Not necessarily. The author said the yellowing is the effect of canine urine on latex paint! Hopefully, that won’t be a problem for paint used on airplanes.

Regarding flexibility, the Web site said the author has taken a painted piece of fabric, wadded it up tightly in his hand, rolled it about and opened it back up with no cracking or other damage to the paint. I visited our local paint store and was shown some test samples that showed the same result. One was a strip of painted plastic that had been bent doubles, and then a larger weight was applied to fix the crease. This didn’t damage the paint. This flexibility makes the paint suitable for use on unsupported fabric surfaces that will be subjected to flexure during normal flight service.

Latex manufacturers all recommend their paint for use on metals and fiberglass that have been prepared by scuff sanding or the use of etching solutions and then carefully cleaned. The EAA site has a query from an aircraft owner seeking information abut how to get latex off an aluminum-skinned plane. If latex has a fault, it’s that it’s impervious to most, if not all, of the normally used paint solvents. There are solvents available that will remove it, however. Check with any well-stocked paint store with knowledgeable salespeople.

Most of the large paint stores now have computerized spectrometers they can use to match any paint sample. The sample is placed in the spectrometer’s viewing window, the computer takes a few minutes to analyze the color components of the sample and then it prints out a formula for mixing the paint. Lighting and eyeballs are removed from the equation. The color chips, that are available at most stores, show the complete spectrum form which colors can be chosen, and the computer can match anything in between the chips. This is particularly useful when trying to repaint repaired surfaces after the surrounding paint has been weathered enough to begin fading. The computer sees the sample, as it is, not what it used to be. The formula it gives matches what it looked at. There may be a difference in the gloss of the weathered paint and the new paint, but that can usually be taken care of with a good wax job.

It seems that homebuilders are really missing something if we don’t at least look at the possibilities for using latex paint on our projects, the nay Sayers not with standing. Where would we be if the Wright boys had listened to their nay saying father without at least testing their ideas?

 

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Jerry Bunner's Painting Method

Experimental Paint For Your Homebuilt

This describes a painting method, which is highly experimental in nature, and if you choose to use this please be advised you do so at your own risk. The ONLY way to paint and finish any airplane is with certified and proven methods.

I have experimented for 10 years using different painting methods to finish fabric on light experimentals. The alternate finishing methods can and will hold up well given proper application and protection from the elements. My first attempt at painting was using Mike Fisher's latex method. It was my conclusion that this would not provide the level of finish that I wanted to see on my airplane. In 1994 I built and finished a Nieuport 11, (Graham Lee Design) and covered it in 1.6oz Stitts. I used a combination of black latex primer to fill the weave of the fabric and industrial polyurethane oil base paint for the finish. This experience started my search for a better method. My goal was a serviceable finish that would look good and avoid the need to spend the large amount of money for the certified stuff!

Here is what I have come up with and I might say it works well, looks good with a nice gloss and is very easy on the pocket book. This finish goes on easy, and the need for elaborate spray painting facilities is eliminated.

STEP 1
Seal aircraft with wood sealer if it is a wooden airplane. There is no need to finish an aluminum tube structure if it is not flown near salt water. For the RagWing Special I am building I am using 2 brush coats of MINWAX OUTDOOR CLEAR SHIELD POLYURETHANE WOOD SEALER. This material is applied unthinned but brushed on in thin coats. I use satin finish so that I may see better where I have brushed.

STEP 2
If you are using the STITS FABRIC (1.7oz) you can brush a thinned coat of POLY-TAC cement over the fabric gluing points. Use your Stits manual for further information on this. The cement can be thinned with MEK SOLVENT and I used about 50/50 cement/thinner. Let this dry and then the fabric can be applied and the cement under neath the fabric can be re activated by brushing 50/50 cement through the fabric at these areas. After the fabric has been applied and shrunk then the tapes that you're using for reinforcement and or rib stitching/attachment can be applied using this same glue combination. A little iron run along the rough spots will smooth them and make sure that they are attached well. I use a Modelers Heat Shrink Cover Iron for this process.

STEP 3
Clean the fabric with a clean cotton cloth and solution of MEK. Just dampen the cloth and wipe the fabric with it. Remember that this stuff is a strong solvent and is capable of melting the glue joints and dissolving your Polyurethane wood sealer. If you just dampen the cleaning cloth and wipe the surface of your covering job this will remove the sizing and other contaminants on the fabric. If you do not do this the paint will not adhere very well.

STEP 4
Using a Good Quality Tac Cloth wipe down the area to be painted BEFORE EVERY STEP!

STEP 5
Using EMPIRE POLYURETHANE LATEX PRIMER thinned with 30% FLOETROL LATEX PAINT CONDITIONER and a 3" FOAM PAINT BRUSH, brush the primer into the fabric using span wise strokes. This is the first coat so do not try to fill the weave completely with this first coat. If you do you will have runs inside the fabric and just in general make a big mess. Repeat this process using cross coats until the fabric weave is filled. This will take 3 to 4 coats. Be sure to let the paint dry well before each application. If you use nice even brush strokes there will be no need to sand before final paint application. The FLOETROL will help the paint flow out into the fabric and be self-leveling. It also adds flexibility to the paint. Minor brush stokes are acceptable to me but you make you own decision about sanding. Preparation is the key to a great final finish. No short cuts here.

STEP 6
Using ENTERPRISE GLOSS POLYURETHANE OIL BASE ENAMEL and a 4" WIDE 1" DIAMETER WHITE FOAM PAINT ROLLER roll the first coat of finish color onto the fabric. The finish will be much smoother if you put the paint on a smooth surface to apply it to the roller. I used wax paper taped to a smooth surface. Remember that you are not trying to apply the complete finish coat in one step. Roll the paint out to a nice even coat and when the paint begins to tack stop rolling. The urethane paint will self level as it begins to cure. All you are doing here is to apply the paint evenly and get most of the air bubbles out of the finish color. Time between coats will be about 24 hours depending on humidity. The finish color will take 2 to 3 coats depending upon the color you choose. You should have a very glossy finish.

STEP 7
After the paint has cured for at least a week, clean the painted surface and wipe on a coat of SON OF A GUN PROTECTANT or similar to protect the paint and give the surface some UV protection. I clean my paint job often and keep a coat of this protectant on at all times.

The paint samples that I have done over the years have spent their entire time out door in all kinds of weather in the state of Indiana. This system seems to hold up well and still look good after all of this abuse. Please do your own samples and satisfy your self as to your technique and results. Best of luck and happy aviating.

For further information contact Jerry Bunner

 

LIST OF MATERIALS

WOOD SEALER

MINWAX CLEAR SHIELD POLYURETHANE WOOD SEALER

LATEX PRIMER

ENTERPRISE BRAND LATEX PRIMER IN WHITE

LATEX CONDITIONER  

FLOETROL BRAND LATEX PAINT CONDITIONER

FINAL COLOR

ENTERPRISE BRAND POLYURETHANE OIL BASED ENAMEL

SOLVENT

MEK

ROLLER

4X1" WHITE FOAM PAINT ROLLERS

 

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Ultraviolet Absorption of Latex Paints by Kirk Huizenga

For many years there has been discussions on the Pietenpol mail list as to the suitability of exterior latex paint as a “system” for covering an aircraft. A number of builders have completed their projects and have used latex paint to cover the fabric with claimed success.

One issue that had not been tested is the ability of latex paint to protect Dacron fabric from damaging UV light. In standard systems, there is a “barrier” layer of paint applied prior to color coats. In the Poly-fiber system this is called Poly-spray. In the past, builders that have used latex paint to cover their fabric have sealed the fabric with black latex paint with the idea that black paint would absorb the most visible light and, hopefully, UV light. This, in turn, would protect the fabric from degradation.

I have considered using latex paint on my Pietenpol rebuild, but wanted to be certain that it would, in-fact protect the fabric from UV degradation. There are builder that have had latex covered fabric for over 10 years without incident, but better safe than sorry. One should not assume that because visible light is being blocked that UV light is also being blocked.

Methodology: I contacted a friend of mine, Dr. Tom Varberg, a Professor of Chemistry at Macalester College in St Paul, MN and asked him about testing the paints. Tom agreed to help me in the testing by using a Beckman DU7400 Spectrometer. The spectrometer can record Transmittance, the amount of visible and ultraviolet light lost (or conversely, absorbed) by a material. Transmittance is the ratio of radiant power (p/o ) that makes it through the substance (paint) to the radiant power (P ) sent into the substance.

Transmittance can then be converted to Absorption (A) with the formula. Tom also supplied me with a small disk of quartz to use as a base for testing the paint at an appropriate thickness - similar to that expected when covering fabric. Quartz does not absorb or restrict UV light in the wavelengths we were PO P T = PO P A = −logT Ultraviolet Absorbtion of Latex Paints by Kirk Huizenga testing (400-200nm) and therefore would not introduce error in the absorption readings.

I applied 4 different paints
1. Kilz Latex White
2. Glidden Exterior Latex-Wooland Green
3. Behr Exterior Flat – Black
4. Poly-Fiber Poly-Brush) to the quartz with a small brush.

After shooting a “blank” to calibrate the spectrometer, one of the painted areas on the disk was placed between the light source and the sensor. The light source flashes on (2 seconds for our test) and the sensor picks-up any energy that makes it through the paint.

The DU7400 gives a graphic representation of Absorbance at each wavelength (in nanometers). In the charts below, I averaged the Absorption of every block of 10 nanometer since there were 600 data points for each sample (from 800 to 200 nanometers).

As a curiosity, I also prepared some lightweight Poly- Fiber® fabric generously given to me by Gil Leiter of St Paul, MN and tested it. I heat shrunk the fabric and tested it with and without paint and Poly-Brush® (generously given by Pietenpoler, Robert Haines).

The results are shown in Chart #2. Limitations: The Beckman DU7400 Spectrometer is limited to an absorption of 4.5 (but we will consider that to be sufficient at T=.0031%) The DU7400 is likely to show erroneous data or noise when at either extreme of its measurement (0 or 4.5). Some data for specific wavelengths may not be accurate, but a trend is obvious

The testing we did does not account for reflection. Any light reflected by the paint would show up as being absorbed. This doesn’t really change the applicability of the test results, but does raise a question of what color paint is the best to use on sealing and protecting the fabric. This is only a test of the UV blocking ability of latex. For many years there has been discussions on the Pietenpol mail list as to the suitability of exterior latex paint as a “system” for covering an aircraft.

A number of builders have completed their projects and have used latex paint to cover the fabric with claimed success. One issue that had not been tested is the ability of latex paint to protect Dacron fabric from damaging UV light. In standard systems, there is a “barrier” layer of paint applied prior to color coats. In the Poly-fiber system this is called Poly-spray. In the past, builders that have used latex paint to cover their fabric have sealed the fabric with black latex paint with the idea that black paint would absorb the most visible light and, hopefully, UV light. This, in turn, would protect the fabric from degradation. I have considered using latex paint on my Pietenpol rebuild, but wanted to be certain that it would, in-fact protect the fabric from UV degradation.

There are builder that have had latex covered fabric for over 10 years without incident, but better safe than sorry. One should not assume that because visible light is being blocked that UV light is also being blocked. Methodology: I contacted a friend of mine, Dr. Tom Varberg, a Professor of Chemistry at Macalester College in St Paul, MN and asked him about testing the paints. Tom agreed to help me in the testing by using a Beckman DU7400 Spectrometer.

The spectrometer can record Transmittance, the amount of visible and ultraviolet light lost (or conversely, absorbed) by a material. Transmittance is the ratio of radiant power that makes it through the substance (paint) to the radiant power sent into the substance. Transmittance can then be converted to Absorption  with the formula. Tom also supplied me with a small disk of quartz to use as a base for testing the paint at an appropriate thickness - similar to that expected when covering fabric. Quartz does not absorb or restrict UV light in the wavelengths we were Ultraviolet paints.

It does not deal with any other issues of using non-certified methods of covering and painting one’s experimental aircraft like longevity, ability to seal the weave, adhesion, or flexibility/brittleness of latex paint. The Poly-Spray was tested with two layers – one on the front of the disk and one on the back. We found that this introduced some errors. Some of the energy that makes it through the first layer of paint gets bounced around between the two layers and gives odd readings.

Conclusions Latex paint can sufficiently blocks UV radiation and therefore protect Dacron fabric. Color does not seem to matter as far as level of absorption differences are extremely minor (in the range of thousands of a percent)

This is a matter open for discussion, but the practice of using black paint as the base/sealing coat on fabric to block UV light may not be the best practice.

White, in theory, would be a better paint for that. White paint has a high amount of Titanium Dioxide, which is highly reflective.

Black paint, on the other hand, gets its “color” from Carbon Black primarily. Black paints have much less reflectivity and more absorption of light.

Now, as I mentioned above, color does not seem to matter much in terms of protecting the fabric, but paint that is more reflective should last longer than paint that is more absorbing of light.

It is not an issue of black or white being better at protecting the fabric, but rather the longevity and protection of the paint itself from breakdown. Brand of paint shouldn’t make much difference in terms of UV protection, but could make a difference in durability and longevity of your paint job.

Resources and Links

Matronics Pietenpol List (with searchable archives)

http://www.matronics.com/pietenpol-list/index.htm

Data (Excel Spreadsheet)

http://mykitplane.com/Planes/filesList2.cfm?AlbumID=5

Dr. Tom Varberg, Professor of Chemistry, Macalester College

http://www.macalester.edu/chemistry/

varberg@macalester.edu

Covering Systems Information

http://polyfiber.com/

http://www.aircraftfinishing.com/

Absorption/Transmittance Info (Beer’s Law)

http://www.shu.ac.uk/schools/sci/chem/tutorials/molspec/beers1.htm

Paint Information

http://www.paintstore.com/archives/misc/14.html

http://www.millenniumchem.com/Products+and+Services/ (TiO2 info)

http://www.paintquality.com/index_quality.html

 

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THE FLYER FAMILY FLIER 
 

Using Residential Latex Paint for Aircraft Finishing 
by Sid Hausding March 2001 
 

Let me start by saying that although this procedure may resemble others that have been out for some time, this method is mine alone. I am responsible for the products chosen and the various methods Inside this issue: and applications described. I understand Fisher may be using all latex, and the Brunner method finishes with an epoxy paint over the latex primer. Many will not agree with my trial and error attempts and many Using Latex Paint may wish to provide better and more experienced philosophy and input. Everything can be improved. I am only describing my covering technique and painting methods as applied to one, privately owned and built aircraft…...mine! I have had my finished project application investigated and looked at by several homebuilders with experience, and by licensed A&P mechanics with lots of repair work behind them. Evaluations were good and the job judged to be just fine. Remember, this is low and slow here, certainly not rocket science with its requirements. 
 

I started searching for a more economical painting application soon after investigating and settling on one design of a kit airplane to buy, build, and eventually fly. All covering techniques and painting methods as applied to the airplane industry were carefully researched and the prices used for the base material and square footage requirements for the size aircraft to be covered were analyzed and found to be out of reach......they all were way too excessive in price for my experiences in painting and weatherproofing projects, and I couldn't understand why the color red was more expensive than others! Except red might be popular, too popular. 
 

I am a carpenter and home remodeling laborer with some combined 30 years bending nails and finishing out residential and commercial buildings. The advent of water based latex paint was a godsend for speed, ease of application and clean-up, not to mention the great price. I have enough experience with this paint to believe in it and to have seen the good results brought forth with the correct preparation, application, and understanding of its limitations. It is not bullet proof, and just like everything else you need to understand how to apply, care for, and what it can do and can't do. I do not consider myself an expert in the latex paint mixtures and techniques of its application, just experienced! 
 

My plane project is a rag and tube, high wing, side by side, with some bare aluminum, and some fiberglass surfaces. This article is on covering the cloth only, but the paint and applications will readily apply to both the other surfaces also, with slightly different base (primer) coatings. 
 

I used a spare 4130 tube, door frame at first, to play with, and to check the various latex primers I had on the shop shelf left over from several carpentry jobs this year. By shrinking some ceconite over the frame I had a surface just like the rest of the plane. 
 

I wound up using Wal-Mart's $10.47 per gallon, Color Place primer (8095 white). Only because is was the right price per gallon, and I intended to add Flotrol to thin and induce a better saturation of the cloth and weave. The mixing directions were adhered to as followed off the container, and I only needed one gallon of the paint. I didn't think I needed any high priced value here, because primer to me is pretty much primer, and this is their 'best' anyway! It certainly seemed to work great. It satisfied my tests on the cloth covered door frame. 
 

I generously applied two coats with the Flotrol mixture using a four inch (4") foam roller and some brushes where the roller wouldn't fit onto the surface(s) due to size, or space of the surface(s) being painted -lifting handles, tight curves, gear mounting, small round tubes, etc.. There was a difference in the texture when dried. The roller left a 'fairly' smooth and consistent skin like surface, and the brush usually left brush stroke ridges evident to my eye, even with the Flotrol. This stuff (latex paints) dries pretty quickly with warm, dry air in the shop, so the coatings were applied back to back on two separate days. No problems were encountered, but be sure you thoroughly mix the Flotrol initially and continue to mix and stir the supply as you go. I saw some 'sweating', or moisture bubbles on the surface now and then, but they evaporated, melted in, and disappeared. When done with each coating, I merely wrapped the foam roller with a sandwich bag and placed it in the refrigerator for convenience and to eliminate the tedious and unnecessary cleaning of the roller. 
 

The Flotrol seemed to thin out the paint too much for my filler coats so I stopped using it after the primer applications. Next I purchased two gallons of Thompson's House and Trim paint ($15.94 per gallon) from Wal-Mart. The one coat 100% acrylic latex satin, high hiding white (T31005). I chose this because it says in the directions on the can cover it has UV protection included in the formula. Name brands were not a consideration here, just price and product labeling. 
 

I used this full strength, after mixing well. I merely poured it into the roller pan, and using the same 4" inch rollers, applied the paint to all surfaces with different directional rolling as I went (helter-skelter). I know some techniques say to do each coat in different directions, well I did mine in all different directions as I went each time. I applied two and three coats until I was satisfied I had hidden some of the features and mistakes of my covering and gluing. Make no mistake here. The paint WONT cover and hide much, and not any major mistakes will be hidden or covered if they are there in the gluing and Dacron covering process. I lightly sanded all the joints, seams, and edges of the tapes with #150 grit, and tested for smoothness. I would wipe my hands over and discover a roughness, some raised threads or curled edges, or dust and lint that had settled into the paint surface. If you sand before the coat really dries out well, you can speed the sanding quite quickly because it will rub up and roll into little pills and elongated 'boogers' with only a little dust. It does goo up the paper, the black oxides (wet or dry types) work best, but I just threw away the used and kept using little four inch squares because it fit my hands well. I think I only cut up and used three or four sheets at $0.85 cents apiece. Where I found any holes, or indentions and imperfections that didn't leave a flat surface that the paint would cover and leave a smooth coating, I squirted a little water soluble, paintable latex caulk. Usually a wet finger tip and smoothing was all that was necessary to blend in the patch and with some paint, presto, instant smooth surface (non-structural). This was for little areas and spots only, of course. 
 

I tried hanging up the flat control surfaces and spraying the paint, but the thickness of the paint was too hard to control and sagging resulted with a most humbling effect on my ego. I was startled to see my perfect spray job sagging into a wet, sticky mess on the bottom edges as well as big runs along any area I had really 'stuck it to' an hour earlier. I used dampened cloths to actually wipe (some rubbing required depending on how quickly I discovered the sags/runs) out the sags and paint, down to the primer, and in some cases back to the cloth. It worked quite well and even allowed me to 'feather' the edges of the messed up areas for later sanding and blending of the repair painting. This set me back several days while this all dried and I carefully built up coats of the primer and satin coatings to try to match the good areas.....lesson learned here was to lay everything as flat as possible and roll or spray. 
 

Now I realize I have suddenly mentioned spraying too. Well, along about the second or third coat of satin 'filler' I realized the finish wasn't getting as smooth (glassy) as I had thought I would like, so I decided to haul out my $100.00 Wagner airless, large project home sprayer. At this point I moved everything back against the walls and taped and stapled painter's plastic (a thin, filmy plastic -drop cloth and over-spray protection) over the work benches and storage shelves around the garage I am using for my hangar. Its a large single area, so I could spread my working surfaces out and had lots of room to paint several pieces at one time. 
 

I have not mentioned any overall project sanding because I didn't do any. Yes, you certainly could sand everything down in between coatings and really bust your butt. I chose to leave it as it built up knowing the latex doesn't need scuffing or have any adhesion problems to itself. I did, as mentioned, look for high spots, specks, or tape edges that raised up or curled - and sanded them quite liberally. I even broke through and cut into the cloth at a few points over hard surfaces or corners, but with some judicial touch up with the paint, and more lighter sanding here, was able to smooth over and blend in any mistakes or problem areas with this easy to use and fairly thick coat material (the latex paint). 
 

I have used this small hand held gun and my commercial duty airless very successfully before and thought, what the hell! I now made sure my wings, tail surfaces, and the side of the fuselage I would be painting was level and used the Wagner sprayer with great success. It did have a propensity to drip after spraying continuously for several minutes, but I carried a damp cloth at all times to wipe the nozzle and tip areas. For the drips that did make it onto my work surfaces a quick swipe with a small brush, kept handy for just this occasion or for little areas, usually allowed the touched up spot to blend in and disappear. The ease with which the latex cleans up after you are done is amazing if you can compare to enamel, or worse, epoxy paints. And its not really toxic, unless you really close off the area you are painting in and shoot a lot of over-spray. I would use a cheap face mask, or as I do, a bandana over the nose and tied behind the neck, ala the masked avenger! Shoot what you need, and exit the area for an hour to let everything settle and keep the dust down while the surface sets up. Good time to take everything into the kitchen and clean the equipment in the sink! Warm, dry, clean, and near the refrigerator! 
 

I purchased two (2) gallons of Ace interior/exterior Royal Hi Gloss Latex Enamel (102A100 high-hiding white [Ace 16664]), on sale, for about $18.00 dollars apiece. My local Ace outlet has a very good looking and friendly paint lady, Denise, and I wanted to impress her with my high finances. This is "washable and durable, acrylic latex, mildew resistant". All the things you would want for your homebuilt project! :-) 
 

Okay, here I went with the sprayer recommendations about flow ability and spraying of thicker solutions. Although the sprayer is supposed to handle the thicker coatings, I added some water (just tap), and mixed very well before proceeding (probably a one to ten ratio, or less) to assist the suction of the little handheld gun from the attached, quart sized, paint container. It worked just fine. 
 

Now, here is where you must practice and learn as you go. The spraying can be quite heavy now, with two or three slow passes over the same area being covered, because your surfaces are level and you want to fill in and hide some of the flaws. Be careful shooting near or on the edges because these areas could run or sag. Most everything is going to be flipped over, so I rightly figured the edges and ends would be getting lots of paint eventually. And they did. By making it heavy now you will achieve the smooth and glassy look that the higher priced painting jobs attain. It can be done. And if one coat isn't to your liking, just let it dry and give it another. My rule of thumb was shoot early in the morning, and then maybe after dinner (eight to ten hours later) so it could dry overnight. Some times it was once per day, and if it rained, I would wait longer for the humidity to return to normal. I do have electric heat available in the hangar (her garage), and used it several times to speed the drying process. The build up of layers and weight really wasn't a consideration here. I only had two thinned primer coats, three filler coatings, and now two or three finish sprayed on coats to achieve a fairly nice finish. How much can a gallon of paint weigh after the liquid medium evaporates? I don't know, but it can't be too bad. 
 

If you will wait for several days at room temperature, the final finish will harden enough to touch and work with so you can assemble the parts without finger prints and smudges in the paint. The added bonus is that you can touch up any mistakes, or boo boos from the assembly process, with a little brush and some full strength latex paint later. I inadvertently dropped one wing tip (see "ground loop in my garage", Avid forum) and was pleasantly surprised to find during the repairs on the tip, the painted surfaces glued up and mated with my Superflite Superbond (it contains acetone) just as good as new. Shrunk down, coated, primed, and painted, it blended in just fine for me. A better finish will be sanded out and painted over to match as closely as possible later. 
 

As you may have noticed I used all white here. No particular reason, except my wing upper surfaces are also the wing tank surfaces too. Meaning if I painted them in a darker color I felt they may draw too much thermal energy from the direct sunlight and cause the fuel to expand in excess. Then leaking, spilling, and evaporation and condensation within the tank itself may be a problem. I realize this article may raise more questions that it answers, but right now the finish is looking good, and a lot of money was saved and labor reduced. My plane has folding wings, a trailer, and several garages and hangars to put it in on a regular basis. I do believe this finish will last a long time. 
 

I now have an all gloss white project ready to add graphics or color designs right over the final coating. Maybe I will do that soon, maybe not. But with the newer rubberized stick on numbers and graphics choices, it should be as easy as painting with………, latex...........! 
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It’s a Beauty! This picture doesn’t do Sid’s paint job justice! Sid lives in Michigan and he would be glad to share his experiences and comments with you. If you’d like to contact Sid just drop me a note by email or regular mail and I will send you his address. It’ll give him something to do besides shovel snow! 

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Painting aircraft with latex paint

Part 1: Latex UV resistance, pros & cons

 

In the spring of 1995 I completed this Ragwing Ultra-Piet (3/4 scale Pietenpol Aircamper) ultralight, using Sherwin-Williams Acrylic Latex over bare Stits Polyfiber fabric. I've received a lot of requests over the years for information on my experiences with the relatively new "latex process," so what follows is what I know from my experience painting and maintaining one airplane. I hope these pages are helpful to you.

Latex paint is very flexible, and therefore well suited for use on unsupported fabric surfaces that will inevitably see flexure in normal flight service. You can wad a piece of latex-painted fabric into a tight ball, and then lay it out flat without seeing any cracks in the paint (I've done it -- it's very convincing). Latex is also very user-friendly, locally available, and dirt cheap compared to "real aircraft paint" (should easily cost hundreds of dollars less to paint an entire airplane).

It is generally recommended to apply some sort of UV barrier below the color coats, and most builders that use latex seem to comply. The most common approach seems to be initial coats of flat black latex, thick enough so that direct light does not pass through it. Then the color coats are applied over the black. Makes the innards of the airplane kinda ugly, I hear. I opted to not add a UV barrier for two reasons. One, I could tell that my Ultra-Piet was already in danger of exceeding the Part 103 weight limit and I wanted to keep the paint job as light as possible (later found to be a very wise move). Two, I didn't feel that a UV barrier was really necessary. If I was still flying the airplane in 10 years, it would probably be ready for new fabric anyway, I figured, UV degradation or no.

To test my theory, I decided to subject a sample of latex-painted fabric to an accelerated aging test, something much harsher than it would see on a hangared (UV-sheltered, for the most part) airplane. So I made a simple wood frame, attached a scrap of the Stits fabric with Poly-Tac around the edges and heat-tautened it. I cut a patch with pinking shears, glued it to the fabric, and cut a square hole through both layers to represent actual patches in the Aircamper around the cables and struts that protrude through the fabric (leaving the fabric unsupported around the hole except for the patch).

Here's an "after" picture (sorry, I failed to take a "before" picture.) In the upper right corner you can see one brushed layer of red latex (wish I would have added a second coat of red). The balance of the sample was brushed with white latex -- one coat over the entire surface and a second coat in the lower left quadrant. (The stains at lower left demonstrate the effects of canine urine on latex paint -- I told you this was going to be a harsh test!)

This panel was leaned outdoors, against my shop, for the next 6 1/2 years, facing south in direct sunlight and directly exposed to the elements. I just brought it inside a couple of weeks ago as it is only now clearly non-airworthy. Every few months I would inspect the panel and try to poke a hole in it by digging in hard with a fingernail. Somewhere around the 6th year, I heard the fabric crinkling during the fingernail test*, although I was unable to repeat this later. Up to this point, I would have flown the material, but now I had to concede some doubt. (*I now think this was the paint cracking at the edge where the fabric was being stretched tight over a corner of the wood frame, and not the fabric itself tearing. I know how to duplicate this sound now, and it seems to be paint-related, not fabric-related.)

Today, after 6 1/2 years, my thumb went through the material during the fingernail test (you can see the new hole in the upper right corner). It should be noted, however, that the material failed in an area that had only received one coat of paint. At this time I cannot get the material to fail in the area with two coats of white paint, even while forcing a thumbnail in with assistance from the other hand. This suggests to me** that it is possible for Stits-type fabric with two or more coats of latex paint (with no other UV barrier) to be left directly in the elements for six years and still be airworthy. (I plead ignorance of how an official fabric-testing instrument would compare to my fingernail test. I'd guess that a real fabric tester might be a bit too pessimistic for lightly-loaded ultralight use, though.) White paint is probably the worst case, too. The darker -- or more opaque --the paint is, the better a UV barrier it will be, and the longer the fabric should be protected from UV degradation. (**Paranoid note to litigious society: I am speaking only for myself, and do not recommend that anyone actually trust their life to fabric and/or paint under the conditions mentioned here!)

This is a close-up of some "ringworm" cracks in the paint. This only occured in the area with two coats, and I can't say exactly when it happened. I'd guess this appeared somewhere around 4-5 years after the test started. I'd also venture a guess that the panel was about -10°F at the time the cracks were formed, and perhaps it was struck by hail,an icycle, or a dog! Despite some cracking, the paint overall still has excellent purchase on the fabric and will not peel or flake off. When the paint is applied in a manner that allows it to soak into the fibers properly (see Part 2), this seems to produce an excellent and long-lasting mechanical bond.

Here is the patch and hole. The edge of the hole is still in excellent condition, but on the left side of the patch you can see the Poly-Tac bond between the fabric and the patch has failed from the outer edge to the hole. The bond is quite intact elsewhere, though, so perhaps my bond wasn't executed as evenly as it should have been.

One weakness of latex that I noticed is a slight sensitivity to gasoline. Spilled gasoline should be wiped off pronto, as it can soften and swell the paint slightly. This swelling seems to go away given time, but it can leave a slightly visible scar or discoloration.

I followed Roger Mann's advice (designer of the Ragwing Ultra-Piet) and applied Armor All to the paint once or twice a year. Roger says that Armor All contains a UV barrier, and it also restores a nice sheen to the paint. I did this 6-8 times to the Aircamper over the years, and the effects on the paint seemed to be nothing but positive.

Another weakness of latex paint seems to be in its resistance to bird droppings. I'm no chemist or biologist, but bird droppings seem to be quite acidic and they will etch their way partially into the paint. Sometimes they'll wash off and leave no trace, other times you'll end up with a lightly-etched reminder of a truly ugly wad of avian excrement that resembled blackberries and cream gone bad. Nasty stuff. But I think the worst scars the airplane incurred were from bird eggs tossed thoughtlessly out of a nest in the hangar's rafters. The goo that ran out of the shells got into the paint big-time and was very difficult to soften and remove.

I never had occasion to repair any latex-painted fabric, so I can't comment on that. But this is mentioned in "Maximum Paint Job, Minimum Cost," a 12/01 Kitplanes article by Kay Fellows about using latex paint on aircraft. Fellows writes, "If you get a hole in the fabric, simply cut a piece of cloth athletic tape with pinking shears. Fit it over the affected area, get out the trusty brush and house paint, and daub it over the tape. This process takes about 10 minutes and gives you more time to fly." I have to question this suggestion, though, as my experience with athletic tape is that it is low in tack. I'd be more interested to know the results of sanding the old paint around the hole and attaching a Polyfiber patch with Poly-Tac. If the Poly-Tac doesn't react negatively or bond poorly with the latex paint, that should create a much stronger patch.

Fellows seems to agree with me on fabric life in general: "As we all know, after 1000 hours or 10 years, you should recover your plane and give it a good once over. I would rather pull the fabric off my plane knowing it only cost $200 than if it cost $1000."

I've concluded that for a low-cost and low-hassle homebuilt airplane, latex paint is an excellent alternative to the high-dollar aircraft paint systems out there. It may not give you a grand champion award at Oshkosh, but properly applied it looks nice enough to satisfy even me. I further conclude that a UV barrier is not worth the cost, hassle, or weight on a hangared airplane (especially on an ultralight). My gut feeling is that a latex-painted airplane that spends most of its life shielded from direct UV rays (under a roof) will remain airworthy and attractive for at least 10 years, and for the money, that's good enough for me.

In Part 2, I'll describe how I actually applied the latex paint to the Aircamper.

Painting aircraft with latex paint

Part 2: How I applied the paint

 

I had the good fortune of working for an employer with a temporary excess of warehouse space, which they let me use to apply the fabric and paint. This would have been really difficult in my crowded and dusty shop. I made special sawhorse caps lined with felt for resting the wing panels on. In the back of the photo you can see me setting up a spray booth with PVC tubing and plastic sheeting (worked fine for me, but be sure to read the caveats in Sid Lloyd's Fabric Covering and Painting page. 2/9/03 note: See photos of my new metal conduit version here). The booth had a roll-up flap for a door on the wall by my left arm, and was vented by a common window fan and furnace filters taped into the opposite wall. Don't worry about using a spark-free fan, because latex vapors are not flammable! (Non-flammable, inflammable, non-inflammable -- don't get me started. It won't burn, dammit.)

 

I'll never regret taking the time to build this "rotisserie" for holding the fuselage. On the front you can see a plywood disc with a lock-pin hole every 45°. The fuselage could be rotated to the best working angle for the task at hand and then locked in place with the black handled pin (not being used in photo). This made a potentially back-breaking job about as effortless as it could be.

After applying the fabric, tapes and reinforcing patches with Poly-Tac and heat-tautening with an iron per the Stits instructions, I applied the color paint directly to the bare fabric with no Poly-Brush and no UV barrier (see Part 1). But first I scrubbed the material with a mild detergent -- this may be a critical step IF your material has any glycol residue in it from the extruding/weaving process. Some builders say it's an issue, others say it isn't. I didn't care to take chances.

I used Sherwin-Williams Acrylic Latex Interior/Exterior High Gloss Enamel (this was in 1995, so the name and/or product may have changed by now). The creamy-white paint for the wings and tail feathers was thinned with water for use in a standard Binks-type spray gun (didn't have an HVLP gun at the time). I don't remember how much I thinned it... maybe 20-30% water, but don't hold me to that. I just thinned it until it had a viscosity similar to oil-based enamels I was familiar with. The first coat should be applied heavily enough so it will soak into and around the fabric fibers, but not so heavy that it soaks through too much and starts running on the back side of the fabric. Allowing the paint to soak in and wrap around the fibers gives you the mechanical bond with the plastic (polyester) fibers which will assure a durable, non-flaking finish. Latex paint will not establish a good chemical bond with plastics -- polyester included -- so a mechanical bond is important.

The thinned paint, especially being very lightly-colored, builds slowly and has a difficult time hiding contrasting features below (such as those hideous black stamps Stits puts on the fabric every few feet). I tried to get by with two coats, but it just wasn't enough. The third coat gave an acceptable opacity and a nice semi-gloss sheen. Sure, I could have added more coats, but I was concerned about the weight of the airframe and wanted to keep it as light as possible.

Many people recommend adding Floetrol, a latex retarder, to help the paint lay out flat before it gets tacky. I'm reasonably sure that Floetrol (mixed per the instructions) gave me headaches. I would spray a panel and these greasy-looking splotches would appear, and the paint would flee the area. After trying several times, having to wipe the fresh paint off immediately before it dried that way, I stopped using the Floetrol and the problem went away. But other people seem to have good results with it (it's mentioned favorably in the 12/01 Kitplanes article "Maximum Paint Job, Minimum Cost"), so I don't know what to say. It seems telling that the Sherwin-Williams clerk tried to discourage me from buying it, but I had been told to use it and by golly I was gonna use it.

I brushed two coats of red onto the fuselage. The brain cells that stored what kind of brush I used are dead or dying, but if I had to guess I'd say that I tried foam brushes but switched to a high-quality bristle brush because of brush stroke problems at the edges of the foam brush. I think I do remember that the first coat (whether sprayed or brushed) should be thinned slightly so that penetration into the fabric fibers is assured. I probably applied a slightly-thinned first coat of red, and then a full-strength second coat. When brushing, the pressure from the brush helps force the paint into the fabric, so it may not need to be thinned as much as a first coat sprayed on. You can peek at the back side of the fabric while you're painting and see what kind of penetration you're getting. I am not aware of anyone using latex paints over fabric that has first been sealed with Poly-Brush -- if you know anything about doing this I'd love to hear about it. My gut feeling is that the latex won't get a decent chemical OR mechanical bond to the Poly-Brush, and is likely to start peeling long before the fabric is ready to be retired. I hear about lots of builders mixing and matching primers, color coats and clear coats from different systems and/or manufacturers, but I consider this an extremely risky practice. There are a lot of unsuccessful (blistering, peeling, etc.) aircraft paint jobs out there to give credence to this opinion, too. A homebuilt airplane represents a HUGE investment of life energy and money; therefore I don't think it is worth it to mix and match different kinds of paint and risk ruining the whole thing. (See 5/11/02 update below)

I had to use careful and consistent brushing technique to keep brush strokes to a minimum on the red surfaces. The red was a more substantial paint, and two coats produced a very satisfactory opacity, although the black Stits stamps could still be seen if you looked closely in good light. If you looked closely with a glare you could see some slight unevenness in the paint's surface (brush strokes), but you had to be looking for them. I've heard a lot of favorable comments about using rollers to apply the paint, but I didn't have enough confidence in them to try it. The Kitplanes article mentions the use of Floetrol to allow the paint to flatten out after rolling.

I remember wet sanding the paint between coats (probably with 400) to knock down the little fuzzies that got in the paint despite my precautions with the booth (I sprayed the walls and floor of the booth with water before painting, to keep dust down and also to raise the humidity level and hopefully retard the paint some.) You can bear down on the sandpaper over unsupported stretches of fabric, but be extremely careful over ribs and other frame members -- you'll sand through the fabric in a heartbeat if you're not careful. I also remember lots of little corners on the pinked edges standing up a bit after each coat of paint. These can be ironed back down, as heat seems to melt both the latex and the underlying Poly-Tac and allows it to re-bond.

 

Personally, even though I am a perfectionist in many ways, I'd much rather be "up here" with a good paint job than "down there" still trying to achieve (and pay for) a perfect paint job. Also, I was soooo tired of the project by the time I got to the painting that I simply didn't have the time or motivation to labor unnecessarily over the paint. Notice the lack of masked trim colors. K.I.S.S.!

If you haven't been there already, Part 1 of this article discusses some pros and cons of using latex for aircraft paint, as well as a description of an accelerated aging test I conducted on Stits Polyfiber with the Sherwin-Williams paint.

5/11/02 Update

Paul Yarnall sent the following message to Tandem Talk:

Hi Everyone... My airbike partner and I are just finishing up an airbike... We covered using the AFS system of water based glue and UV barrier... great stuff to work with... and plan to shoot the color this weekend in Sherwin Williams latex. We had done a bunch of test panels in latex and we were getting pretty discouraged since none of the techniques variously described using foam brushes or rollers produced a finish we were willing to commit to our beautiful wings. When we dumped the Floetrol, reduced with 20% water and applied with a $60 Harbor Frieght HVLP conversion gun, the results were fantastic. We have attempted to abuse the latex panels and there is little doubt as to the bonding of the latex to the AFS Cecofill... they seem to be very compatible.

I'm very interested in the long-term success of the latex paint over the Cecofill, and hope that Paul will stay in touch and let us know how it performs over the years. This seems like an ideal solution if the latex paint will stay firmly attached to the Cecofill through years of temperature/humidity cycles. We also need to know if spilled gasoline and/or oil will have any deleterious effects on the bond between the two components. I'm hoping that it works great, Paul.

2/9/03 Update

Paul sent the following additional details about his experiences with AFS products and latex paints.

Hi Doug....

Sorry to hear about your unhappy results with the AFS products. I don't recall if I had mentioned it before, but we had intended to use the AFS for the topcoats but that turned into a disaster and we washed it off before it cured... that's when we started on the latex quest.

I am surprised that you also had problems with the CecoFill. I can say that I have never tried spraying it. I seem to recall that even AFS recommended brushing it on, (but don't hold me to that).

(ed. note: The CecoFill bottle says "For best results we recommend spraying." It does later say that it can be brushed or rolled, though.)

The tool of choice is the throw away foam brush found in every hardware store. I think the brush method forces the cecofil into the weave and overcomes the surface tension that aggravates the flowing out we are used to seeing with solvent based coatings. I have been using a water based clear polyurethane for some wood working projects... the only way I can get a nice wetted out surface is by spraying (same HVLP gravity gun I used on the Airbikes) but if the spray coat is too light it doesn't flow and will display a classic "orange peel" effect we use to associate with silicone contamination when spraying lacquers and enamels. You would swear that the surface was contaminated but if the coat was applied a little heavier it would flow on very nicely. Also the tiny holes in the wood grain is very resistant to filling and flowing over ... just like the weave in the fabric.

You may have no desire to see or smell the stuff again, but you might find it instructive to try a few test panels with a foam brush. Even without sanding, the brush marks are very subtle after it is completely cured.

As for filling in the blanks in my own latex experience that you requested, I was able to piece together the following... (thought I had written some extensive notes but can't find them)...

On a CecoFill prepped surface, we applied Sherwin Williams A100 Exterior White Latex Primer, their part number 600-0483. We reduced it with water. Sherwin Williams says not to reduce with more than 5% water. I think we went a little more than that, but I did write down that it was 125 sec. using a viscosity cup. We used the $50 gravity feed HVLP "conversion" gun from Central tools. A terrific value. It sprays better than a $700 Croix gun I used for years until I tried this.

As I said before, my partner and I barged ahead and had some Sherwin Williams "Exterior Accents" 25 year paint mixed before we experimented with it. Big mistake. No combination of water, pressure, Flotrol, cursing or arm waving would make that stuff spray a finish we could stand to look at. We tried some others to the same result. In desperation we went down the paint isle at our local home center reading labels to find something else to try. We took home a quart.. . (we got smart and stopped buying gallons)... of Dutch Boy, Exterior Door & Trim, Acrylic Latex, HI-Gloss Enamel. The reason I decided to try it was the factory allowance for spraying of up to 1 pint per gallon of water... 12.5%. Spraying this stuff was as nice as the other was bad! It saved our bacon on this project. In gallons the neutral base is part number 16-809. Tint to your color of choice.

As I said before, the latex shows some swelling when exposed to fuel, but seems to do no permanent harm. We elected to make our wing tanks removable by putting an aluminum tank cover on just as you would do on a "real" airplane. Minor fuel spills evaporate before it reaches the fabric most of the time. We also are using only straight pump gas with no oil so any spills don't carry any oil to the fabric either. (We converted both Airbikes engines (one 377 and one 447) to oil injection. We also converted both to "free air" cooling. Together these changes have made for very happy engines and much happier pilots, NO MIXING!!.)

Back to the spraying... despite unfortunate experiences such as your own with CecoFill, I still consider it a great filler/UV barrier that is very easy to use and is virtually fume free. I have used it on real airplanes and on the Airbikes and I whole heartedly recommend it, BRUSHED on. The Sherwin Williams A100 went on beautifully, covered well and is a great base for any other top color. The Dutch Boy did the same for color. But for anyone contemplating a "rubber skin" airplane, throw together a dozen 12" x 12" square wood frames, staple on some scrap dacron, shrink it per the usual way, and try all the materials and methods you want to use before attacking the airplane. You can work out the best thinning ratios, best spray settings and techniques and so on. It is worth the few hours of extra work. Once all the variables are nailed down the entire Airbike can be painted in two days.. one for the white and the color the next day.

Doug, I have attached a picture of our "bikes". There is a couple of feet of snow in front of both doors so this is the best I can do for now.

This is about all I have to offer on latex and Airbikes, but I would be happy to address questions. Doug, you can use any of this that you wish and you can edit it to fit your space as you see fit.

Sincerely,    Paul Y.