How about polyurethane varnish?
 

Can anyone tell me why sheeted balsa, electric aircraft can't be covered with water base polyurethane varnish instead of using a Monocote type product? We obviously don't need fuel-proof finishing. I have no idea what the weight penalty might. Thanks for your input.

RE: How about polyurethane varnish?
 

pguiet, Most of the guys that use fiberglass mesh over foam wings use polyurethane to attach/fill
the mesh instead of fiberglass resin. I don't think the balsa/poly would have as much strength as the iron on covering or fiberglass mat and poly. I don't know if this helps or not.
Happy flying,
Bud

RE: How about polyurethane varnish?
 

You can cover it as you suggested. I cover all my fully sheeted planes with Deft....a laquer, then paint over it. Lighter than any plastic film if you don't put on too many coats of paint.

RE: How about polyurethane varnish?
 

Minwax polycrylic is what your looking for. Chech out similiar post under "foamies--Finishing Foam".
Happy flying,
Bud