RCU Forums - Fabric covering

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I'm getting ready to try my hand at applying fabric covering, to a 1/5 scale Cub. I'll be using Sig Koverall. Here is what I was thinking of doing.

1. Seal balsa with several coats of Nitrate dope.

2. Apply stix-it around perimeter of assemblies.

3. Iron on fabric

4. Shrink fabric with iron & or heat gun.

5. Seal fabric with water base polyurethane. Several coats,
light sanding w/ 400 grit wet/dry between coats.

6. 2 or 3 coats sandable gray automotive primer (spray bomb).
Sand w/ 600 grit wet/dry.

7. Apply color coat(s) using automotive paint (more spray bombs).

8. Fuel proof (glow fuel) using 2 part clear polyurethane.

Does this sound like a workable plan?
Suggestions, alternatives, tips...all are welcome.

TIA

Mike

Hey your on your way to a plan but I think you could loose some of your steps.

1. Nitrate>Nitrate you can use to attach the farbric works great

2 Stxit all you have to do is Iron on the fabric

3 which ever 1or 2 you choose will hold the fabric very well

4 Koverall is best controlled with an Iron as it can shrink alot and twist up your plane if you go to far, shrink it just enough to take out the slack and wrinkles.

5 I have never filled the weave with other than Nitrate dope so I can't say how Poly U would work. But I can say Koverall will fuzz if you sand it directly (read not good)

6 If your fabric is filled you don't need to prime why do it

7 Most auto paints are fuel proof do some tests to make sure.

If you follow your plan you may have some compatability problems and I would check to see how the Poly sticks to the fabric.
And a very nice looking heavy plane

If you want a nice scale finnish you could.
1 Nitrate or Stixit the fabric to the Airframe
2 Fill the weave with Nitrate dope 2 to3 coats 25%thinned
3 Use Byuterate Dope or most any Fuel proof Paint you choose for the color coats ,most any thing will go OVER Nitrate

Den

I was going to post a reply, but Den has said it all!

Jetts

why dont you just use 21st century fabric. Its painted already . Just iron it on. Its too easy right? Yes, it comes in cub yellow.
All of my planes are , and will forever be covered in 21st century fabric
d

I use Sig Coverall on some of my planes and I like it, it's almost bullet proof and it never wrinkles. It's takes alittle more time to apply and smells bad but its worth it.

Just want to second that "don't use a heat gun" to shrink the fabric.... polyester shrink is heat activated... the higher the heat... the more the shrink up to about 325 degrees(I think) at which time a fabric like coverall will have shrunk a full 10-12%. It takes a pretty strong structure to withstand this much polyester shrink. A heat gun has no way to control the temperature and can actually overheat the fabric to the point where it will lose, forever, it's elasticity/tautness. A good iron like the coverite iron that is able to regulate the temperature within +- 5 degrees is not only great... it is a must. Good luck.

Dan

My first time with coverall I hit the material with to much heat and snapped a trailing edge right off.

Thanks for all the input. I think I'll stick with established techniques and materials. Thans especially on the heads up on using the iron over the heat gun.

Mike

I used water-based poly to fill Sig Koverall on two planes now with great results. Two coats fill the weave.

Be careful of grain direction of fabric. It shrinks more in one direction than the other. It can cause warpage of parts or sagging between wing ribs.

Jim

I'm glad you brought up grain. What is the rule of thumb
with regard to grain direction?

TIA
MIke

I took some scraps and used a heat to see which direction seemed to shrink more. You can also make a little test frame and shrink it. I don't remember whether the grain goes accross the sheet or lengthwise.

I covered a whole biplane with Coverite one time and when the plane was already painted I noticed that on one of the bottom wings the fabric between the ribs was sunk in. Looked kind of weird to have the fabric straight accross on 3 wings and sunk in on one.

Jim

MJ, Tmoth,
I recall reading about the "grain", and which way it was, It was either in the paper that comes with the covering, or in the section on covering that is in the Sig catalog.

Jetts