As long as you are talking sheeted surfaces (foam or built-up), I think epoxy is much easier, because you don't need to worry about adhesion or incompatible chemicals. It's glue with pigment, it sticks to anything and itself just fine.
My airplanes have *many* repairs, some pretty drastic, and I routinely get 17-18 points. And the only thing wrong with the finish is the fact that it is clear nitrate dope underneath, and *that* has gotten fuel in it and self destructed underneath the otherwise intact epoxy paint.
Brett
I happen to go along with Brett, they are about the same when finished. However, it’s the same old problem finding suitable wood is the key. For that reason alone is why most are now open bay assembly’s. There are other things that can be used to get fantastic finishes such as, glasscloth, CF vail, tissue and iron on film. The attached photos are the stab & elevators of my latest design P-Force XL. They are covered with Sig Plyspan tissue and then covered with SLC covering and turned out really good. Process is as follows!
(1) Lightly sand parts with different grit sandpaper from 220 to 400 grit sandpaper.
(2) Give parts one coat of nitrate dope thinned 70% thinner, and 30% dope and allow to dry at least 12 hours. When dry, lightly sand with 400 grit sandpaper and remove the dust with a tack-cloth. The only reason for the thin coat of dope was to insure that the parts would not warp when the wet tissue was applied to the structure.
(3) I want to try a new product to attach the plyspan instead of the old dope method. The Deluxe Eze-Drop worked as intended. I did find the Eza-Kote finishing resin worked better than the Eze-Dope to attach the plyspan to the stab & elevators. Apply a light coat of the Eze-Kote to the out side edge’s of the stab. Wet the plyspan with water by passing it under a facet and ringing out the excess water by crumpling the plyspan in your hand and squeezing the plyspan covering (Do not coat the entire stabilizer with Eze-Kore) Place the plyspan on the part and remove as many wrinkles as possible. Apply an additional coat of Eze-Kote to the out side edge of the plyspan tissue using a 3/8” paint brush and allow to dry. When dry then trim off the excess covering with an #11 Exato or razor blade. Follow the above to cover other the side. When the covering and Eze-Kote are dry, lightly sand the edges with 220 grit sandpaper.
(4) cut a piece of SLC covering oversized giving you at least 2” of extra in each direction. Place you Sealing Iron on 200 degrees (about 2 on the iron). The film has two sides, one very smooth, second side has a slight rubber feel, which is the glue side to go aginset the tissue. Place a piece of SCL on the part and iron in place starting in the center and working your way to the ends pushing the air bubbles out from under the SCL covering as you go.
As you approach the leading and trailing edge, roll the iron over and around the leading & trailing edges
attaching the film to the edges. Replete the above to cover the remaining side. Turn the heat up to 250 to 275 degrees, and carefully seal down the edges of the film. Note; Overlap the covering at least 1/4” on small parts and 1/2 to 3/4 for larger parts.
Mikey