So the only reason you prefer laquer based vs. water based is wood warpage?

Specifically, I'm looking to possibly glass my next pattern plane. The wings and tail feathers are 1/16" contest bonded to styrofoam with polyurethane glue. I agree with you that this would not warp.

The fuselage is 1/8" contest balsa with formers every 12 or so inches.

I guess I could use water base on the sheeted foam and laquer based on the rest. Is there any difference once the water or laquer dries? I read on your website that the laquer leaves a gummy residue. How big a hassle is it to remove this residue?

Do you foresee any problems using 2-part automotive primer over the Poly U?