Homemade FCS Weed Fins for Surfboard

[Alton]

Finally found some time to (re-)build homemade FCS weed fins using Clay's technique:

1. Cut out a mould using slippery plastic (milk jug) with 40° slope and join sides with duck tape
2. Roughen fin surface (leading edge) with sand paper and clean with isopropyl alcohol
3. Fill mould with 5-minute epoxy ($1.50 from Dollarama)
4. Wrap leading edge of fin with mould and epoxy to extend it
5. Allow epoxy 5 minutes to harden before removing mould
6. Allow epoxy 24 hours for curing before use
7. Remount extended fins on surfboard
8. Fill air gaps between weed fins and surfboard with Marine Goop
9. Smooth down leading edge with sand paper

weedfins.jpg (71.71 KiB) Viewed 12411 times

[gabrielb]

That s great. Alton, hope it holds. fins take a lot of pressure under heavy waves, play with different materials if issues, epoxy may peel off, etc.

[Alton]

That s great. Alton, hope it holds. fins take a lot of pressure under heavy waves, play with different materials if issues, epoxy may peel off, etc.

My old weed fin (over 1 year old) suffered from several chips when I hit debris so I had to rebuild it. This is the only down side.

Otherwise, there is no wear and no peeling if you roughen and clean the surface before applying the epoxy.

For many years Clay, Rob W and Francis use the same technique and their weed fins are solid.

My bigger problem is losing fins (3 in 1 year) when I hit bottom/logs/rocks and/or FCS screws loosen. I resolved that by applying Marine Goop sealant around the entire fin where it joins with the top of the fin box This also fills any air gaps to prevent cavitation and catching more weeds.

Removing the fin was easy. Just take a sharp knife to cut the fin loose and peel off the excess Marine Goop sealant.

The thought of losing 3 Makani Weed Fins is horrifying ... that's why I prefer to build my own ... or boost to shake off the weeds like Jeff/Tweegster is doing in the picture below

[gabrielb]

David once asked me why I chose glassed in fins instead of changeable fins. Reason is that they come loose if they hit anything hard enough and sink to bottom, glassed-in fins take double the hit to come loose. I agree gluing them better chance to stick around.

[Alton]

Weed fins cured, re-mounted and sealed ... Ready for Action!!!

weedfins.jpg (265.63 KiB) Viewed 12305 times

[gabrielb]

they look very sweet.

if you find epoxy being too soft and getting dented , coat epoxy with super glue (3 coats+), sand after.

[Alton]

Added Step 9. Smooth down leading edge with sand paper

First day on the water, the weed fins were still catching weeds but they didn't seem to slow me down.

Next day, I smoothed down the leading edges with sand paper (as recommended by Clay) and tested them at the last Locust session. Intentionally hitting big patches of weed, the weed fins did not catch a single strand of weed.

Mission accomplished - tons of weed, no problemo