Balsa fin finishing technique

While working on my Estes Silver Comet, I was worried a bit about the ability of the fins to survive hard landings. I was also not looking forward to filling the grain in those monsters. So I decided to laminate the fins with regular paper to provide strength and a ready made surface for painting.

The key to this technique is the adhesive: regular wood glue will cause the paper to wrinkle up and make it difficult to smooth out unless you're really careful. Well, I don't really have that kind of patience... and since I was looking for an easy way out, I didn't want to create more work than filling the grain with Elmer's Fill 'n' Finish (my previous method of finishing fins) would take.

I used the adhesive I use to mount photographs: Rollataq (found in office and photo supply stores). It's water based, so cleanup is easy, and (most importantly) it doesn't wrinkle the paper! Here're some easy steps to finely finished fins:

  • Sand the fins with 400 grit sandpaper while they're still on the die cut sheets.
  • Cut out the fins, stack and sand the edges as usual. Remove any sanding dust with a tackcloth.
  • Apply a layer of Rollataq adhesive on a sheet of typing paper. The area covered should be larger than the fin.
  • Press a fin onto the glued area, flip it over and burnish the paper down with a roller.
  • Let the glue dry for 10 or 15 minutes, then flip it over so the paper side is on your cutting surface.
  • Using a sharp X-acto knife, trim the excess paper by 'outlining' the fin with your knife.
  • Repeat the process for the other side of the fin.
  • I then sanded all the fin edges (with the exception of the root edge) round.
  • Prime and paint as usual.
  • Now if only I can figure out how to apply this to balsa cones and transitions...

    Ninfinger self-portrait
    Sven Knudson