Fuselage covering

[cposer]

Ok, I am covering starting the fuselage sides. The poly fiber manual says to coat aluminum parts with 3:1 poly brush/reducer. So I did that around the door joggles. Now do you then use Poly tak to glue the fabric to the door joggles with the base coat of poly brush OR use poly brush through the fabric to attach them to the joggles? Will using poly tak against the base coat of poly brush be a strong enough bond for the shrinking? Or should I remove the base poly brush coat and attach the side fabric to the door joggles using just Poly tak? This is my first time covering so sometimes the poly manual doesn't make sense.

[jmodguy]

Don’t know about the poly system but I think you should start with covering the bottom first...

[avidflyer]

I don't have time right now to look in my manual, but if you are reading it right, then follow what it says. I do know that large surfaces get a couple of layers of polybrush applied before you cover them. Then when you apply the poly brush it will go through the fabric and bond with that underlayer of polybrush. JImChuk

[cposer]

Yeah I get that large surfaces would get a couple coats of poly brush, such as the top of the fuel tank. But will poly tak to poly brush be as strong as tak to aluminum?


The belly is already covered Jmod:)

[avidflyer]

I quickly glanced through my manual, and don't see the part you are referring to. What page or such??? JImChuk

[aviator79]

It will probably work fine either way, but I think it would be best to remove the Poly-Brush from the area that you're going to glue the fabric down on the door joggles to ensure the best adhesion. In Section 5 of the manual there is a note in bold that says not to mix Poly Brush and Poly Tak, which is basically what happens if you try to lay Poly Tak on top of Poly Brush because the solvents in the Poly Tak dissolve the Poly Brush and it mixes together.

On a wing leading edge, its not a big deal because you glue the other layer of fabric on top to make a cemented seam. Once it heat-shrunk, the original Poly Tak over Poly Brush could completely give way and the fabric wouldn't go anywhere. This isn't the case at the door joggle though, so it might be best to go for the best adhesion possible, which would be Poly Tak directly on primed and scuffed Aluminum.

[Dave S]

Clyde,


I'd agree with Brian. Best to forget about what a component is made of (aluminum) and consider the purpose of the joint around the joggle. Where a person is gluing down an edge of the fabric - stick with polytac alone for a secure joint. The upper fuel tank surface of the wing is a different deal - it's not a fabric edge.

[N213RV]

If you are gluing down edges of material, use polytak. If you are laying fabric over surfaces that are flat (fuel tanks, etc) and NOT on the edges of the cloth, then use the 2 layers of poly brush/reducer on those areas. If you use poly brush on edges they will not hold once you shrink the cloth.