Boat Wrap

[barrystrs]

[barrystrs]

[89 CHARLIE]

[Chappy]

[BlackRain]

[yankeflyer]

It looks like I will need to recover both wings. The boat wrap looks good to me.

[yankeflyer]

I googled boat wrap and it is available and relatively inexpensive, the link below is

for 4 mm shrink wrap

[yankeflyer]

This eBay address is for the shrinkwrap that they have for sale and one of them is offering their shrinkwrap for 2.50 ft. and a it's 20 ft. wide in white.

The clear shrinkwrap is not as clear as tedlar also there appears to be plenty of high-quality tapes available.

No doubt the last thing you want to say is what you're using it for.

ebay shrink wrap

[Shannon]

For you guys who are interested Uline carries shrink wrap/boat wrap as well as the shrink guns too. This is the same place I buy my foam and doubled sided Tedlar attachment tapes from.

http://www.uline.com/BL_2414/Marine-Ind ... hrink-Film

[Chappy]

Boat Wrap Covering System Report

This year at the Canadian UPAC Summer Fly-in and convention a 2 place Lazair trainer was displayed and flown that was covered in conventional boat wrap (BW). It had a brand new cover job and it was beautiful even before the custom paint job applied to parts of it. The Lazair was covered in the standard 7 mil white material that is the most popular type used on boats to protect them during winter storage. The big Lazair made many flights while I was there and looked to perform well. The white covering is extremely bright in the direct rays of the sun and can be difficult to look at at times!

The fellow that brought the trainer and had done the covering job on it was Mark Allin of Sportflyer Aviation. According to him he has covered half a dozen Lazairs in boat wrap over the past several years. He has developed a quite unique method and was generous in sharing it by giving a hands-on seminar Saturday afternoon. The seminar was rather well attended - even (the designer of the Lazair) Dale Kramer was in attendance. There was another fellow in attendance that also had experience covering a Lazair in boat wrap or a very similar material. Unfortunately I failed to get his name and contact info. He offered some interesting suggestions.

The system is extremely simple. The old covering is removed from the plane. The old adhesives aren't even removed but can be if desired. The surface, let's use a wing for the example, is draped in boat wrap and trimmed for a modest overlap, maybe 2" or so at the trailing edge. The seam is made at the trailing edge of the wing. Because the BW comes in much wider rolls than Mylar or Tedlar, it allows the BW to wrap around and cover the spar, producing only a trailing edge seam. Boat wrap repair tape is used in small pieces to temporarily hold the covering in position and hold the material snug without big bagging of the covering. A small modeling iron just exactly like sold in Hobby Shops for shrinking mono-cote covering or fabric is used. It is set fairly hot, about 8 out of 10 IIRC. It is slowly worked over the overlapped BW along the trailing edges. The technique is to heat the BW and press it against the metal frame below, crushing and heat sealing the two layers of BW. DO NOT try to rub or glide the iron across the covering material. This will smear/tear the material as it gets soft and almost sticky when very hot, and you will mess things up! Remove the small pieces of tape as you move along the seams. After working along all of the seam, go back and work the seam some more on each side of the tubing. This will then give you a wider fused joint. So, on the trailing edge, that would give you a sealed seam that wraps around the trailing edge some. Now do the finish trimming of the extra material. Also, seal the root area. As far as the wing tips, he just works them the same way, all in one continuous piece. This solves the problem of having to make a separate wing tip covering. He omits the small metal trim piece used on top of the covering. This does give a rather "plump" wing tip. I don't know why the piece couldn't be used and have a more normal shaped wingtip.

A heat gun is then directed on to all the seams. Enough heat is directed onto the mashed down seams that they will actually smooth out and melt together better, and will look nicer. Also, the covering will begin to pull up some of its slack in the large panels. It takes a little practice to figure out how much heat to use without over doing it, but it's not too hard. After doing the whole seam, you can direct heat onto the large panels to finish pulling them up tight. A word of caution here. If you just pour on the heat, the top covering can actually sag so much that it can contact the other side of the wing. If they touch while very hot, the two sides will weld together and your job is ruined! I like to shrink Tedlar panels in a vertical position and that should help somewhat in keeping the panels apart. Take it slow until you get used to the behavior of the material during shrinking.

Although the BW manuals recommend not using heat guns to shrink it, it seems to work fine on the small panels we will be shrinking. On a typical boat being wrapped, the areas to shrink are quite large, and propane powered heat guns work better by heating large areas more evenly. Heat guns tend to cause thinning of the BW if you try to shrink large areas over and over. If you do burn a hole in the material, it can be repaired in a couple ways. The way they do it on boats is just to apply pieces of repair tape made from the same material. It is applied over fully tightened panels - don't try to shrink the tape too. That will work for us. A second method was demonstrated during the seminar by one of the participants that also had some experience using BW on Lazairs. A piece of BW was cut for a patch and placed over the hole/damaged area. It was then covered with a piece of heavy Mylar, 10 mil I think. An iron is then used to heat and seal the patch to the wing. This takes somewhat more heat than we used before. You'll have to experiment to find out how much is enough. The materials will get so hot as to also stick to the Mylar cover. WAIT until everything has cooled off. Then the Mylar piece will peal right off leaving a nice patch below that is permanently attached - no adhesives to worry about! Very cool. But the best deal is to just take your time and not burn any holes in the material to begin with.

You'll notice I didn't mention any tapes involved in sticking the BW to the wing, etc. That's because none are being used. There's nothing to keep you from using them, Mark just hasn't been using them and so far so good. He has fitted external capstrips behind the engines to restrict the covering from beating against the ribs, and also one out at the rib between the main wing and the aileron panel I believe. None have been used on the bottom of the wing. All this goes against everything I've ever learned about fabric covering over the years, but there it was and it appears to work on a Lazair without problems (so far, anyway). Like I said, a bunch of Lazairs have been covered this way and some have several years of trouble free service. Personally, I plan on using a process similar to a normal Lazair covering process - sort of a belt and suspenders approach, you might say, when I cover with BW. Another option discussed was to cover the ribs in BW as above. Then after the wing covering is done, the covering could be heat sealed to the ribs. Or, perhaps, the ribs could be spiral wrapped from front to back with tape made from the same boat wrap material, and the cover could be sealed to it. That might be faster, but certainly it should be tested first to see if they heat seal together as well as two layers of boat wrap. Also, the affect of all that heat required to seal the materials, whether BW or repair tape, would have on the foam rib material. No one knows as of now.

A significant thing to note here is that BW is sourced all over the place at boatyards, and also over the internet, It comes in quite large rolls, usually enough to practice some and still do a couple airframes. From what I've been told, the 6 and 7 mil materials are actually the same. I'm not sure why they are sold under two different weights. A typical roll is 12 by 175 feet and shipping will likely cost almost the same as a roll of the material. Even so, if you don't use tapes, as Mark has, you can cover an airframe for $100-$200! When you consider that a Tedlar covering job will run you well over a thousand bucks for materials now (if you can even source it at all), it's quite a bargain. Yes, it will add some weight to the airframe, and that is unfortunate especially for us gravitationally challenged types (you know who you are). Add tapes if you are chicken like me, and it's still quite affordable. White (not clear) Tedlar tape is available commercially at fairly reasonable cost, but BW seaming/repair tape should be adequate for capping seams if you feel like doing that in addition to heat sealing. I found that the heat welding process, if done properly, provided quite a positive bond. Basically you have welded the BW layers into one piece.

I had great concerns about rip stopping the cover by using tapes or adhesive on the top and bottom of the ribs. What I found was that the BW doesn't propagate a rip. It is a rather soft material and just distorts a bit, then stops. One of the guys said that they had held a panel with a hole in it out the window of a car and then tried to get it to rip or tear at fairly high speeds. The material would not allow the damage to enlarge or tear. Still, normal 3M Ultra high strength foam tape for the ribs isn't too expensive. One thing to note here is that the soft nature of the BW unfortunately makes it easier to damage when trailering the wings. You can't be careless and bang or drag the wings out of supports or slings as it may dig in and hole it. I did see evidence of this in a place or two on Mark's newly covered 2 place Lazair's spars.

Overall, boat wrap used as a covering material impressed me. That surprised me as I had grave reservations about it being used. From what I saw and learned, I would have little now - other than not using some form of rib attachment. Even though I saw with my own eyes the 2 place flying around without any tapes used, I guess I'm just too old to feel comfortable doing it that way on my plane.

Hopefully there were others that attended the seminar that will chip in and add to the discussion, or add more details on their covering process. I waited to report on it here in the hope that someone else with experience, and more literate than I, would. But finally I thought that this information needed to be brought out into the daylight for more people to discuss.

As I mentioned above, Dale Kramer attended the seminar, and I think even he was impressed with the material and processes developed. Like myself, I think he was leery of the lack of attachment (tapes), and also the weight of the material. But we had to admit it worked and flew safely from what we witnessed. Time and experience will tell. Just be warned that if you proceed down this road for covering your plane you will be a real test pilot as compared to Mylar or Tedlar covering. I am only reporting what I saw and learned; I am not advocating anyone's use of it - mandatory statement of release of liability here!

I hope this answers a few of the questions many have had with regard to using boat wrap as an alternate covering material.

Anybody using boat wrap want to add to/correct this information? As I haven't done any actual covering with boat wrap other than playing with it a bit at the convention, I can not be considered an expert by any stretch of the imagination and won't be held liable if you try this and something goes horribly wrong. All I'm doing is reporting on what I saw/learned at the seminar.

Chappy