Fish fins....where??

Just about done with the f-board…need fins. I was going to attempt to make my own keels…but am looking for someone who already produces them…and the cost. Double foil preferably but any info will do…thanks.

Sean W.

Glass ons…or just ones made of glass that I could remove the tab and glass…thanks.


I’m sure you can find someone to make your keels. Why not make your own? Its not hard and kind of fun. I make mine from ply scraps from my buddies cabinet shop. Cost is almost nothing(glass and resin). The wood is lighter than glass/resin fins and they look bitchen. I’d be glad to put some templates in the mail. Mike

I’m about to make a set of fish fins. Rooster, care to send some templates my way?



E mail me at and give me your address. I’ll put’em on paper and mail them to you. Mike


Thanks,I guess I won’t be lazy…and make my own. I would like to see/have a set of templates that you use.I will shoot you an email ,thanks in advance for the templates.

Sean W.

I got some keels from Rainbowfins in Cali.


They worked out pretty good for me.

I got three sets from Rainbow. One set to go in big boxes. They are beautiful. Change colors depending on the light. I’m not sure whether the box mounts need to be beafed-up, though.

Boxes not supported by the stringer, and used with fins taller than 5.25", generally need the minimum of two layers of 4 oz capping.

If you surf strong, or in faster waves, small 1/8" spider woodies, emanating outwards from the center of the box, is a good idea…oh, OK, insect is enough legs.


Could you elaborate concerning spider/insect woodies from the center of the box,please. ARe you talking about routing out grooves from the box to reinforce the area. Kind of like Mr. Spitzers split tail reinforcers? Thanks, Mike

I was thinking depth of box strips of wood, pointing out from the center 4" of the box (the unsupported middle) like straight legs on an insect.

Keeps the center 4" of the box from flexing outwards, causing delam, causing catastrophic failure in the whole installation.

You can use 4 or 6, depending on your athetics.

Woodies along the box works OK, but are not as weight to strength efficient.

Don’t forget to cap both the top and the bottom of the board over the finboxes.


Did you like the ones you made or bought better? Mine will be glassed with patches anyway so no insect dohickeys for me. I found some plywood scraps from a boat place near me,guy said it was “marine plywood” does that just means treated for rot huh? Did you happen to send out the templates yet…anxious,thanks.

Better be sure your fins are no taller than 5.75", even with capping, as leverage really increases after that size. After 6", insect legs for sure.

No need for “marine grade”, as you seal it with resin and glass anyways. Just get what you like the looks of, cut it out, and some foil, seal coat, then glass it and it’s ready for install.


Yes, I’ve mailed them to everyone who asked, I believe. LeeDD is right about the type of ply. I’m a novice builder. Sounds like Lee know his stuff backward and forward. I have not used marine ply. I have used maple ply, baltic burch ply, and teak ply. The teak looks good. As for preference of ply vs. fiberglass I cannot say. They are on different boards with different riding charactoristics. All the boards work well, but my faovorite is a 6’6" fish with 9x5 maple plys. I have been riding that board since January. I like the ply better because I make them myself, they work good, and they look good. I have not used the fiberglass fins mounted in boxes, yet. Mike

What about balsa as a core material and some serious glass (carbon fiber or that texallium stuff maybe?) to reinforce it? … a lot of the carbon lite fins have foam cores.

Wood is used normally just for the looks

The core is just something you glass over, giving you shape and form.

Hollow is avoided due to heat and cold, expansion and contraction.

You can use an old 80 page, Sunday newpaper if you wanted to.

I remember seeing a hollow fin that was filled with water and snowflakes, so it looked like it was snowing inside the fin, when the board was moved.

" remember seeing a hollow fin that was filled with water and snowflakes, so it looked like it was snowing inside the fin, when the board was moved."

Dude, I just snarfed (laughing so hard while imbibing that the beverage exits via one’s nasal passage) the water I was drinking when I read that.

Thanks for the info.

I’m old, seen lots of weird things, that’s all.

The thought brought to mind the image of huge platform shoes with goldfish inside.

I was wondering about the balsa core because I was concerned about the strength/flex/resonance of such a fin as compared to something made of a denser wood. Sounds like I won’t know until I try.

Definetely try!

Hollow can be really stiff, but heat and cold…

All the $250 fins in windsurfing are carbon over foam core…some styro 1.25lbs.

They flex, but just a little, and snap right back. Some are 26" long!

A keel, with a 7+ base and only 5.5 tall, should not flex at all even with regular glass.