I'm to the point I need to figure out a couple of things out on my current build. I'm planning on a polycrylic base coat, applying silkspan to my fully sheeted (foam) wing. My big question is prefinish with polycrylic & silkspan, then install in fuse, or install first, then finish?

I'm prepared either way. I just want to get it right. Color coats will either be Rustoleum, spray can car paint, or perhaps the spray appliance epoxy paint (primarily white), with perhaps 2K clear as final top coat.

Steve

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I feel very strongly both ways.  Either way will work.  I think most finish components then assemble.  I go the opposite route, probably because I compose a plane in leu of building one.  I like to see the fully assembled plane while I can still change something.  Good luck

Ken

I guess my question boils down to will the epoxy used to glue in the wing hold if I pre-finish the wing with polycrylic? I know people pre-finish with silkspan & dope all the time and there's not really much of an issue installing the wing in those cases. But...that's dope, not polycrylic.

Steve

One of the reasons I install before covering is so that I can reinforce the wing fuselage joint from the inside with glass and epoxy at the seams.  Some folks overlap the center section covering to strengthen the wing joint.  That seemed to come into vogue when people stopped double planking the center sections and a lot of very nice planes were retired with folded wings when they couldn't handle the added weight and lift of the modern stunter.  I have no doubt that a covered wing sealed with polyacrylic will be strong enough if Epoxied and has even small fillets, especially if it is a profile.  On a profile you can drill an 1/8" hole from the bottom through the LE and TE and slide in a dowel if you are worried about the joint failing.  As a side note, I sealed the frame on my Trifecta (the twin tail profile) with polycrylic before gluing the wing to the fuselage.  It is covered with Monokote after a thorough sanding.

Ken

What is the plane you are covering?  Profile or Full Body?

Electric Magician with Tom Dixon foam wings, so profile.

This is the covering material I have and am planning to use: https://www.amazon.com/dp/B004ZB9HFO

Steve

I have never covered with tissue on a CL again after my grandmother put her hand through my outboard wing right before appearance judging at the 1964 NATS and cost me a place in the Walker flyoff.  Guess it psychological.  Get it on and get out to the circles while it is still Fall.  Best flying weather in the year.

Ken

I have never used polycrylic, and I rarely, if ever these days, build profiles.  That said, I prefer a wood-to-wood joint, no matter if profile or full fuselage.  Then finish.  It might not matter any, but I would rather not find out the hard way.

I make balsa fillets, sanded with paper wrapped around a piece of brass tubing.  Attach silkspan to bare wood with dope, overlapping the fuselage-wing fillet.  I never had a structural failure with this method.

Profiles are vibrators and known to stress crack at the wing/fuse joint unless well glued or epoxied.   I'd definitely prefer to do the wood to wood joint here and finish after.   That's the way I do them all anyway.

Dave