Filling EPU foam

[Todd]

I bought a used Stone BLue Spectre 2 and it had been pretty messed up around one of the tail boom wing joins. I cleaned up the hole and filled it with expanding polyurethane. I cut new channels and in the in tact EPS and moved the booms slightly inward after cutting channels with a soldering iron.

My question is, I heard that you can use some sort of lightweight spackle for a filling material in the urethane. I have reather large holes in it from where I carved and shaped it to conform to the original airfoil and I want to fill these and smooth the surface out. Anyone have any ideas of a product that can do this?

If not then I am down to Lowes to try and find something.

OOn a full scale composite airplane i would probably use a microballoon slurry. On this that seems like overkill.

Thanks!

 

[Craftydan]

Todd if it's only to fill in voids to smooth the airframe skin, then yes. if the void needs to be filled for strength, then no.

keep in mind, it's not a durable surface. you'll need to cover it with paint or film (or glass) to keep it from being scratched away.

 

[Todd]

Do you have any product names in mind? It is not structural. I already gooped in a new rib to fill the void and the airplane has a carbon Arrow Shaft running through it. The fill is merely cosmetic.

Thanks!

Todd

 

[RAM]

I think lightweight spackle is what you are talking about. There are a few youtube videos out there on how to do it.

found this one, might help, https://www.youtube.com/watch?v=Uoev17PvrjI

 

[TTMR]

I'd avoid doing the micro gallons simply because they would be less flexible and would likely pop out the first time a stress was placed on the part.