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PostPosted: Sun Mar 14, 2010 11:03 am
by Shannon
I read somewhere where the expected lifespan of the Boat wrap was approx. 9 months max exposed to direct sun. What take did the guys have on expected time before recover. I'm thinking maybe 4 year max lifespan on a hangar stored regular flyer.

If I didn't know any better I'd say that 2-seater has a painted tubing fuselage.

PostPosted: Sun Mar 14, 2010 6:51 pm
by Chappy
Hi Shannon,

Mark has been covering Lazairs in boat wrap for about five years now and claims all are still flying. Last year there were six flying and two more were being worked on. He claims no problems with any of the ones flying. He was also investigating a better quality covering material similar to boat wrap, but I don't know anything more about that. The thing to remember though is that they are all in Canada, I believe, and your experience down on the Gulf Coast might be (and probably would be) considerably different as the sun is a lot stronger there over a summer season. So real world life span is something still to be determined in the South. Keeping direct sun off of any covering is a good idea if you want to maximize it's life. I know you can extend the life of Mylar from less than one season to over ten if you are militant about keeping the sun off it when not being flown.

Not that you would be interested, but some of the others on the list closer to him might like to know that Mark plans on offering to cover a Lazair for $750 (I assume Canadian currency) including labor and materials. I don't think he is all that far from the UPAC Convention site in Kitchener, Ontario. He was still working actively on refining the process last time we talked in December. He also offers general repair work on Lazairs and flight instruction.


Mark's Plane flying at the UPAC Convention (photo by

PostPosted: Tue Mar 16, 2010 3:01 pm
by Shannon
I know virtually nothing about the Boat Wrap so it's hard for me to make educated comments about it. I can only throw in a few comments based on speculation-conjecture and what "I would" probably do if planning to use it. I can clearly see however that the 2-seater has some capstrips placed on the first few ribs. I'm really wondering why at a minimum they have not been installed on all ribs (top). The Ultraflight method with Tedlar (surely a far superior covering to BW) was to have capstrips on all the ribs at the top. Second I hope the guys using the Boat Wrap are not pushing the lifespan beyond reasonable expectations. Like Mylar I'm guessing the Boat Wrap will eventually get brittle with long term UV exposure. A failure with Boat Wrap could be similiar to a failure of Mylar. Unlike Tedlar the failure of Mylar is abrupt and complete. Tedlar covering usually fails as a result of attachment tape problems with progressive "creeping and loosening". The film itself does not appear to be affected by UV for a 20+ year lifespan on a hangar stored plane.

This is just me talking but I'd probably put on capstrips (7/8-1" wide 2024 .025 flat) both top and bottom if using Boat Wrap. I do not like the idea of any covering "Free Floating" off the bottom of the ribs. Personally I don't like the "Puffy" Wingtips either. Having the Wingtip capstrips in place ties the covering and structure together to form what I'm guessing is a stronger overall assembly. Same goes for the wing ribs....the covering is part of the structure...think about it.

I could just sit back and say nothing about the Boat Wrap being that I don't plan to use it (I have a bit of Tedlar to use). It appears however that the Boat Wrap is viable and currently working well for people so it warrants consideration. I do however think people need to investigate any possible limitations and consider those limitations in their decision to utilize it. Bottom line is that Boat Wrap isn't Tedlar or Fabric which are both well proven and long lasting. Time will tell if the Boat Wrap is a good idea or not when it's time to recover. We'll See.

Again just me talking but I'd stay with Tedlar as my first choice for covering followed by 1.7oz Fabric. Both of these installed "properly" are 20+ year lifespan coverings. It's hard for me to get past this fact when looking at other possible alternatives.

PostPosted: Tue Mar 16, 2010 10:21 pm
by Chappy
I agree with much of what you're saying Shannon. After messing with flying machines most of my life, the idea that you could put a bag of 6 mil plastic over the wings and heat seal the edges and go fly around w/o immediately getting killed or smashed up is preposterous; and yet, there they are. My report was only that, a report, because I was fortunate enough to see the covering, see it fly (and in a 2 place which I would think would be even more likely to exhibit problems because of higher wing and power loading), and attend Mark's hands-on seminar. I felt the Lazair community deserved to be exposed to the material and process as it stands now, or more accurately last summer, as Mark claims to be upgrading the process as he gets more experience with it.

Fresh material is very, very tough and damage does not propagate, even less so than Tedlar I think. Your point about damage to older, UV exposed material has to be a very real concern as I think it's ability to resist major failure will degrade rapidly over time, but again that will be totally dependant on total UV exposure. Remember, this stuff is three times thicker than Mylar, and it's been demonstrated that Mylar this thick has much more resistance to UV (and just dropping the thickness of Mylar down to 1.5 mil caused it to degrade much quicker than standard 2 mil material). Besides, leave a Lazair tied down outside year round here in Virginia, and UV exposure will be the least of your worries!

With the prospect of a viable covering system (not quite there yet for me, but some obviously feel differently) at a very attractive materials cost, I think we will see this develop. As of right now, you can cover a Lazair in boat wrap for what George wants for a roll of his custom made Tedlar tape and still have enough left over to take the family out for dinner! The economics will drive it. If you can source BW locally w/o shipping, we're talking about an incredibly affordable covering materials cost of maybe one-tenth that of Tedlar/tapes or fabric/glue/uv block/paint coverings. And that's assuming the use of capstrips on all coverings.

Capstrips - there's a topic in itself. No Lazairs kits that came supplied with Mylar were ever fitted with cap strips. None were needed as the rubber based tape adhesives never failed unless roasted during film shrinking. Small sections of the double foam rib tape sometimes failed, but that was generally due to damage to the ribs first. Mylar doesn't hold the continuous spring-like tension on the covering that Tedlar does. Many, many Lazairs using Tedlar have operated for decades without the use of capstrips. Capstrips became a suggested REPAIR when Tedlar tapes and foam tapes separated. Several causes were identified. Gross over shrinking of the covering was the main cause (this is not possible with Mylar!), followed by occasional shipments of Tedlar tape that had inferior adhesive. These tapes were custom made for Ultraflight by small companies and they eventually found out that they couldn't rely on the suppliers to produce top quality tape each time. Finally, residue from solvents seemed to adversely affect tape adhesion. Acetone seemed to be the main one, and unfortunately it had been recommended by the factory for prepping before taping. And the acrylic adhesive was a pressure sensitive type that needed to be rubbed down well within the first couple hours of installation to cure properly. This was not fully realized when the switch to Tedlar was made. With all this going on, and Tedlar really the only alternative to Mylar, the quick fix was capstrips. Fabric was really never seriously considered because it didn't jive with Ultraflight's marketing. A Lazair was sold as an easy and fast to build kit. Adding a contemporary fabric covering job basically ruined that claim, not to mention the effect on kit material costs.

I think 2010 will turn out to be a very interesting year for us with the efforts to develop new affordable covering systems and alternative 4 cycle engines. Let's hope it turns out to be a safe year too for everybody!


PostPosted: Wed Mar 17, 2010 3:55 pm
by gdewsbury
Just a thought regarding using the boat wrap as a sock with out fastening it down.

My initial thought was, "that`s just not right".

But, think about how many ultralights and all hang gliders I know of use exactly that. Dacron sale cloth is sewn into a sock that is just pulled over the spars made from tubiing.`The shape of the sail is from battens that are slid into pockets on the sail. Keep an eye on the sail material to see when it is degraded and replace.
From what I`ve seen the BW will last a few years at the very least and can be replaced much faster than any thing with adhesives and a fraction the cost. With hanger storage who knows wat the life span will be?
The suppliers recomend white for most applications because it does not heat up much at all and blue for locations farther north than me because it will heat up a bit and melt some of the snow off.
It was strange to touch the white plastic I had on for a season and find the material was cool to the touch mid afternoon in July and August.

PostPosted: Sat Mar 20, 2010 5:39 am
by xgary
Great report Chappy.

I will tell you guys that I have a 20 x 30 hoop style building here and it is going into the 6 th year now. IT has I think 2 mil poly white stuff on it from a greenhouse supplier and is has help up very well.
It has has 2 feet of snow on it at times until it slides off. up to 6 feet at side that has slide off. Very tough. I few tears in it but they do not seem to keep tearing. I just add tape over top and it seems fine.

Would it work on a lazair? most likely

Would I use it ? I doubt it . I have used many times 1.7 oz fabric and some of it is 15 year plus old now and still in great shape. I do not have issues with fabric lifting off ribs but you could use capstrips if you like. The foam tape I never really think that it could hold as it is always ( WET ) when you use fabric cement it hardens and you glue plus fillet forms the bond. You could rib stick if you wanted to.

I have another lazair recover job booked for next few months...... it i will likely be fabric.

You can be the test pilot on new materials. -- thanks but no thanks.

PostPosted: Sat Mar 20, 2010 7:12 pm
by Shannon
I think most of my concerns are with the LONG TERM aspects of using a different covering like the Boat Wrap. Unlike most I've had the chance to slap an old Mylar covering and have it blow apart in tattered shards. I've had a chance to look at the effects of extreme sun on old yellowed foam tape and how the Tedlar creeps and loosens. I've also seen how a capstriped and protected (Hangared) Tedlar covering can absolutely still be viable after 25years (Lets not forget Dale is flying 80's Tedlar). Lastly I've covered in 2.7 and 1.7oz fabric (established process) and know it's long lasting good stuff when put on "right". My hope is that guys will not push the limits of a new "economical" covering. Me.....personally..... I gladly pay $1.00/ft for new Tedlar tape to go with Tedlar that's going to last 20+ years. I think back to many years ago when a guy here was killed when his rotten covering let go and came off (not on a Lazair). Very stupid thing to ever let something like that cost someone their life.

PostPosted: Sat Mar 20, 2010 8:53 pm
by JPXman
i think the main thing boat wrap offers is the ease of re-cover. like those you mention shannon, i think the people who fly with questionable covering are trying to get "one more flight" off their old rotten covering before undertaking a long and arduous process of recovering with tedlar/mylar (I group them together when talking of recovering).

if boat wrap only takes an afternoon of snipping off the old stuff and sliding a new sock on, then I don't think people would delay recovering a bird that is questionable. and if you are in a group like they have at the allin's farm (which is an awesome place with awesome people) then it could just become a bi-annual thing for all the lazairheads to get together and recover everyone's at the same time. if you had 6 people recovering 6 airplanes i'd bet you could do them all in one day.


PostPosted: Tue Mar 23, 2010 11:24 pm
by Chappy
A buddy just salvaged a couple large pieces of boat wrap for me that had been used to protect large flight simulators in shipment. I was extremely impressed with how well the matching tape adhered. Also, where touching areas had been heat shrunk you could not pull them apart - even in the areas that looked to have had relatively little heat applied, just enough to touch. You could pull hard enough (with difficulty) on the small areas to eventually rip the film but not pull them apart. Very impressive. I used some of it to wrap the removable hardtop for my old convertible in to store it in. I dragged the wrapped up hardtop on it's smooth flat roof just ten feet or so across a grass covered drive before lifting and walking it into the shed. Just that small amount of abrasion ripped about 2 dozen small (1/16 to 1/8 inch) holes in the film. It's tough yet soft. Obviously, transporting wings covered in BW without damaging the covering will take care. I saw just a tiny bit of similar damage to Mark's brand new covering job on the front of one spar. It appeared to have happened while loading or unlaoding the wing from the trailer.

Once the BW is heat sealed together (as described in the procedure) with an iron and then heat gun, it will no doubt be welded just as surely as a Mig welder welds steel. But it ain't fast, and there's a lot to do. It may be possible to design a hot iron with a roller tip that could speed things up a bit. You should make up for it a bit with the reduced amount of time doing the final shrinking, but I suspect we would be surprised by the time it takes to weld up all the seams in a boat wrap cover job.


PostPosted: Sun Mar 28, 2010 3:09 pm
by yankeflyer
A lot of good investigative reporting and analysis on the boat wrap. Thank you for your interest in the project.