Wood Fin / Molded Base

First fin - Made for an old Hobie bolt through style box. Epoxy lams, UV hotcoat(s), poly gloss, and the base is molded epoxy. Thanks for all the help. Best, Herb Bean

Very nice. Good work.

Nice job! Did you use the box as the mold or perhaps take a casting of an old fin?

John - I cast an old fin’s base in latex. Then put the wooden fin in the mold and poured in the epoxy. I was surprised how clean and easy it all popped right out of the mold (beeswax as a release agent).


Right nice looking work, but I have as usual some questions…

Is there any halo on this fin? I’m thinking about rock resistance. Your post says you just stuck the wood into the mold and poured epoxy, so I guess not, but the process description gets me to thinking, you betcha.

I have wanted to make a wood fin with a FU base for a long time, for lightness, but couldn’t see how to make it both strong and rock resistant, yet easy to shape the base without more tooling than I now have (router and table saw).

Does the epoxy base have any fiber reinforcement? I’m concerned that the base may be brittle despite my wanting to believe in the toughness of epoxy. Can you add milled fiber or just cut some short lengths in, without entraining too much air (maybe this would lighten the mix and actually be a good thing)?

Is there a production future in fins like this? SHIT YES!!! (Thoughth there have to be patent/licensing issues involved in duplicating someone else’s fin base. SHHHH.)


It does have a slight 1/8 halo around the fin. I used 3 layers of six ounce and had it as wide as a 3/8 inch but didn’t particularly like the affect/look so I sanded most of it away. The board’s main usage will also be in sandy conditions. If I was in a rocky area, I would have surely kept it thicker.

Its base being brittle is a valid concern that I have too. I did add in milled fibers (and tint) but I think their addition to strength is marginal (if any). Also it’s hard to see in the pic but on molded base, the epoxy does thin out pretty close to the wood on the rear of the fin creating a probable weak area. Next time, I’d make the fin a little thinner so that the epoxy can be thicker. In addition, some glass reinforcing would probably help as well. I’d like to know the thoughts of others on its strength. For now, I’ll baby it when setting the board down, waxing, and riding too shallow.


Herb Bean