Mylar

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Postby Jean-Marc AugŽ » Sun Mar 14, 2004 5:54 pm

does white mylar exist and why should'nt we use it .After all it is very light and if kept away from the sun it will last much longer. and how about painting the clear one, to give it an extra chance to last longer. it was used in the past and I have seen lazair flying with it for many years.
Thanks in advence for your replys. J.M.A
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Postby lazair » Mon Mar 15, 2004 4:11 pm

The Original Mylar was clear. I am not sure of the properties of the white mylar. Can you confirm the specs and source ?

Good topic , But I tell you TEDALR is the way to go or fabric it you not mind 20lbs weight extra with paint.

Tedlar was a combination of MYLAR and TEFLON and we have a few still flying with 20 yr PLUS tedlar with NO PROBLEMS but they are hangared.


Hope this helps and see you soon.

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Postby Ray » Fri Jun 25, 2004 5:35 pm

What thickness is the mylar?

Since I cant find Tedlar, myler is my next preference.
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Postby ozzie » Fri Jun 25, 2004 8:00 pm

thickness of mylar is .002 thou. there are several mylar covered mk 1 still with original mylar here in australia flying with no problem secret is to keep them covered out of the sun. whilst searching for tedlar/mylar i found mylar easier to obtain and was going to puchase some from fiberglass laminaters who use it for vacume bagging, until i found an original roll of mylar that was from an unbuilt kit. it seems to have stored well over the years.
other products have come on the market in the last 20 yrs since so try looking at polymer products. currently waiting for a reply from a supplier who uses it to print our money on. some falcon owners are using polylam as well. i personally prefer mylar after the stories of tape slipping with tedlar and it,s milky appearance. and loosing it's taughtness as well. tip do not tell them it for an aircraft. tell them it is for laminating solar panels or hothouse ect. good luck.
BLUE SKIES AND FULL TANKS
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Postby Chappy » Sat Jun 26, 2004 11:42 pm

Ray,

Mylar's life is limited by exposure to ultraviolet light, and to a lesser degree exposure to certain chemicals. The worst chemical is ammonia. Unfortunately, some people have used Windex as a spot cleaner on Mylar covered wings, and the ammonia in it will attack the Mylar and shorten its life. I have seen Mylar that didn't make it through a single summer here in Virginia when left outside. I have also had Mylar covering that was well protected from light last well over ten years, perhaps fifteen. If Mylar is always protected except for flight hours, the tapes will probably be the limiting factor in the life of a cover job. I think that generally holds true for Tedlar. I know many people cover Lazairs with fabric and paints, but I don't like that for lots of reasons:

Fabric/paint is HEAVY. It WILL affect the performance of your Lazair.
Fabric/paint is more work to install. It's messy. It is much harder to repair. It makes inspection and minor repairs of the wing structure/ribs/controls much more difficult.
Fabric/paint is expensive.
Owner's are prone to leave their planes tied down outside because they aren't concerned about UV damage, where they are easily damaged by strong storm winds, acid rain, snow loads and vandals.
And, most of all, it just doesn't look like a real Lazair to me without the clear/translucent coverings of Mylar/Tedlar!

I think the reason no one likes Mylar is because there are very few Lazair builders still around to share their experiences with Mylar. It's the cheapest covering traditionally used on a Lazair, so having to recover isn't as bad as with the other materials. Once you have done a cover job of two, you'll be amazed at how fast you can do it. I've covered planes without any assistance (and with a lot less fingerprints on the inside of the wings too). The worst part by far of recovering a Lazair is getting all the old adhesive crap off the wings.

Mylar is much prettier than Tedlar (crystal clear Vs frosted). It's much cheaper. It's available commercially; Tedlar is only available in large amounts, it seems. I think it's easier to stress relieve (shrink) than Tedlar. Mylar/rubber adhesive tapes are cheaper and easier to find. The rubber adhesive is much more resistant to slipping/creaping, unlike the acrylic adhesive used on the 2 inch Tedlar tapes that were custom made for Ultraflight and varied all over the place in quality. The 2 inch Mylar tape was/is made by 3M, with real quality control. Tedlar holds paint much better than Mylar, I have been told. Paint also adds weight.

Mylar was supplied in the same dimensions as Tedlar. Both were 2 mil (.002 inch) thick, 100 foot long by 50 inch wide (IIRC) roll. The 2 inch tapes were also both 2 mil thick.

Obviously, if you can't find a way to keep the sun off your Lazair when not flying it, do not use Mylar.

The next cover job I do I will probably use Mylar again. If I do, I'll post my material costs.

Chappy
Lazair #25, covered in Mylar except for Tedlar covered elevudders
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Postby lazair » Sun Jun 27, 2004 6:47 am

TEDLAR vs MYLAR

What would you pay for a roll of TEDLAR ?

vs A roll of Mylar.

To me tedlar at 1000.00 a roll is a much better investment than Mylar had it been free.

Sorry, I wold use fabic before Mylar and accept the extra 25 lbs of weight.

Once you done a few recover and realize it alot of work to clean up and be ready for revcover... Tedlar if can be found is the most sensible alternative.


Now lets find some tedlar.



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Postby Shannon » Sun Jun 27, 2004 4:58 pm

I'd have to agree. Tedlar is definitely the way to go on the wings if you can get it. This is where I differ just a bit though. For the hard to cover things like the tail and ailerons I like the 1.7oz Poly-Fiber. Even with sealing coat, UV coat, and top coat paint I found that only scant ounces were added versus using Tedlar. Obviously if you used the heavier certified aircraft fabric or multiple coats of UV blocker and paint the weight would go up considerably. Installation of the Poly-Fiber is no problem done all by yourself (try this with Tedlar) with no "helping" hands. Installing Poly-Fiber however does require that you be handy with a paint gun. Obviously installing Poly-Fiber costs more than Tedlar. A good bit more with the costs of covering supplies, coatings, glue, brushes, auto paint, ect.....
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Postby JPXman » Sun Jun 27, 2004 9:59 pm

just to throw in my 2 cents of experience...

i've only covered with tedlar (2 airplanes) and the best thing you can do for yourself is to buy Mike McKusick's wingtips :)

As for the covering, once the wings were clean, covering with clear film is a SNAP. You can do a wing in a day with a buddy and a case of beer, including shrinking. I bought the poly-fibre book when i was thinking of going that way, but to me it seemed far more complicated and easier to screw up. The first wing I did with tedlar I screwed up BADLY - I'm talkin after i taped it down, there was easily TWO INCHES OF VERTICAL SLOP in the tedlar - i was so mad. But, patient shrinking and another case of beer tightened it right up! Don't be afraid of covering with tedlar - the extra work to find the stuff is worth it. It's out there, so if you need it, find it! There's always a way!
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Postby b diedenhofen » Mon Jun 28, 2004 11:31 am

Just got to throw my two cents in on this one. I covered mine with cloth and I cannot see how it is possible that it added much more than 5 lbs to the overall weight. The cloth itself is only slightly heavier than the Tedlar and the tapes required and the silver sealer used was in a 10 lb can most of which is sovent, which evaporates out. The remaining solids are not that heavy. If you go with the poyfibre process, you will have some further weight because of rib stitching and reenforcement tapes as well as multiple coats of sealer and paint. The very best way to go with cloth is the Hipec process. Get the uncertified cloth from Aircraft Spruce and Specialty, very inexpensive and get the glue and sunbarrier from Falconar Avia.com. The process is super easy and quick. Simply glue the cloth around the parimeter, then heat shrink. When you brush the special sunbarrier onto the shrunken cloth, it is designed to soak right through and actuall glues the cloth to the ribs. No need for rib stitching or tapes. With the silver sunbarrier applied, you have a covering job that will be good for 15 years in the sun. I left mine silver and it looks great. If you prefer color, simply roll and brush a good quality latex house paint. It is inexpensive, durable and again, not very heavy for two thin coats. As for repair, it's simple. You cut a patch, put glue around the parimeter and place it over the damaged area. Heat shrink and coat with sunbarrier and you're done. I would have covered mine with Tedlar if it were more readily available to keep the plane looking origonal, however I am extremely pleased with the durability and finish of the cloth covered version. After spending 3 days cleaning all of the goo off of the airframe when I removed the origonal Tedlar, I really don't want to do that again either. When it's time to recover my bird, I will simply peel off the old cloth, give it a light sanding and glue on the new.

Brian
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Postby Guest » Mon Jun 28, 2004 1:31 pm

Did you wrap the fabric all the way around the D-cell or did you attach it to the trailing edge of the D-cells like the Tedlar is attached ?
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