I'm about to embark on my first attempt at covering with Koverall and dope. I have a quart of the nitrate stuff, and also a qt of what Sig calls Lite-Coat. It describes itself as a low shrink butyrate.

Everthing I've read says to use regular buytrate over the nitrate stuff for the first two coats, is this true? Or will the lite-coat stuff work?


Thanks



(1/5 scale cub, readybfor covering! :} )

First a short lesson on dope. All Butyrate shrinks. Non-tautening Butyrate shrinks less than Tautening. Butyrate Lite is nothing less than Non-tautening Butyrate. Since we started using polyester, there is no use for Tautening Butyrate on polyester as it shrinks with heat. Using a shrinking Butyrate causes cracks and peeling away from the fabric.

For silkspan or silk or linen you need the Tautening Dope.

Then there is the product that doesn't shrink and chemically bonds and takes less coats.

Nitrate is OK for sticking down the Koveral, general surface prep, and a few initial coats to fill grain on silkspan/silk. I use a lot of it for this sort of thing. It sands easier than the butyrates and seems to be a bit stickier when adhering coverings.

With the Koveral being a heat shrink material, the Lite-Coat is fine once the covering is stuck down with the nitrate and has been shrunk.

Lite-Coat is what the aircraft trade terms a "non-tautening" Butyrate. It is just as fuel proof as the tautening Sig SuperCoat.

Nitrate vs butyrate.

Nitrate sticks to almost everything, and you can put almost anything over it.

Butyrate sticks only to butyrate, and you can put only butyrate ovet it.

That having been said, I am not even sure that what they call butyrate is the same stuff that it used to be. The EPA has gotten in and stirred the pot. Manufacturers have been forced to make everything much worse that it used to be:-(((((((((((((((

Les

p.s., You might check out Aircraft Spruce. I believe the last real dope, I got from them, but as I recall, nothing smaller than quarts.

I thought that nitrate was not fuel proof at all???

Yes, quarts. But their quarts are almost the same price as Sig or Brodak pints. I bought some recently, Aircraft Spruce quart $18, Brodak pint $16. Add the thinner (Brodak $11.50/quart, Aircraft Spruce $25/gallon) and you'll spend the same amount of money to get twice as much material.

I've never had a problem with Butyrate over Nitrate dope.

Great info, Smithcreek! Thanks!

Ok, cool- thanks everyone for the good info. I was talking with someone yesterday and was told that using Koverall can be very similar to doing fiberglass work, which made sense to me. Guess I'll stick with the nitrate, lay up the fabric as best I can without shrinking, then use the iron where needed before switching to the Lite Coat. Sure was hoping to have this project flying this season, but that's how it goes! [>:]

"I thought that nitrate was not fuel proof at all??? "

Nitrate is not nitro proof, nor very nitro resistant, that is the purpose of putting butyrate over it.

Les

I get all my covering suplies from AIRCRAFT spruce,what ever you need they have it.

I got my dope from Wicks Aircraft Supplies in Highland IL.

Stits coatings are an alternative to dope
http://www.stits.com/store/index.html