G10 fin repair

Ray Dunakin

Well-Known Member
Jan 9, 2003
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I just repaired a rocket that had a large triangular piece torn out of the leading edge of a fin. The rest of the rocket was in good shape, so I didn't want to trash it. Here's how I made the repair...

The fin is 1/16" G10. First I sanded off all the paint from the damaged fin, and cleaned up the torn edges.

Next I coated the area around the tear with epoxy on one side, and laid down a pre-cut piece of 6oz fiberglass which was large enough to extend more than an inch around all sides of the hole. I worked plenty of epoxy into it, then covered it with a sheet of wax paper.

Next, I turned to the other side of the fin, placing it on the edge of a table so that it remained flat. The wax paper prevented it from sticking to the table.
I then coated the second side of the fin with epoxy around the torn area. I filled the hole in the fin with a couple small triangles of heavy Carbon fiber cloth that I happened to have on hand, and worked in some epoxy. This was topped with 6oz glass as on the first side, and another sheet of wax paper was placed over it and any air bubbles carefully squeegeed out.

I then clamped the fin firmly between two flat plates and left it to cure over night. The next day I removed the clamps, peeled off the wax paper, and sanded the excess epoxy from the edges of the fin. The result is a smooth, sturdy repair that will be almost undetectable after painting!


Well-Known Member
Feb 22, 2003
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Excellent repair idea there Ray !

You should write that up with pics and send it to the Online site for inclusion in their how-to articles.

As someone who is scared of fiberglassing, I'm green with envy how you guys make these airframes and fins look so purtty. 8)

Thanks for the great post Ray.


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