How to change a broken fin plug on your surfboard

• Sebas R


• 25 Jun 2016

Our surfboards are very fragile, and one area that usually suffers a lot is the fin plugs area. A wipe out on a fin, or touch the bottom with a fin can cause a break of the plug or tear off the board.

But remember that in life, except death, everything has a solution, and in this article we will explain step by step how to change a FCS fin plug. It is not very difficult, you do not need to be a pro shaper, it is enough if you are a little handy and that you want to learn new things.

You will need the following materials:

– Polyester resin

– Styrene waxed

– Glass bubbles

– Fiberglass

– A fin plug

– A fin

And at the following tools:

– A cutter

– Sanding paper of 80, 120, 180, 240, 320.

– A rotary sander

1. Remove the broken fin plug from your surfboard

Use for this a pliers, to remove the plug from the board, as a dentist would extract a tooth, trying to do as little damage as possible.

2. Clean the area around the fin plug gap

Start by removing the damaged and detached fiberglass from the foam. You can use a cutter and an 80-thick sandpaper.

3. Rebuild the area

It is necessary to rebuild the area, this area receives the pressure of the fins, and it is important to get it robust. Cut pieces of fiberglass, and place it in areas without fiberglass, the parts where you see the foam.

Apply the polyester resin, to impregnate the fiberglass, until get it completely clear. You can use a squeegee, or if you do not have one, any plastic spatula or plastic card. There are two families of polyester resins: the solar that hardens with UV rays, and the classic one that catalyzes with a PMEC catalyst. If you use solar resin, you must work in an area protected from natural light, and once you have finished with the application of the resin, you can expose your surfboard to the sun, and let it catalyze in a few minutes. If you use a resin with a catalyst, you should work at a temperature between 17 and 25 degrees, and use between 1 and 3% of PMEC catalyst.

Once the fiberglass and the resin are hard, you can apply a small gel coat, a mixture of resin with 5% of waxed styrene. The gel coat is what will allow you to sand the area later on.

Finish by sanding the inside of the hole to give it its initial round shape.

4. Place the fin plug

First, prepare a mixture of polyester resin with glass bubbles. Mixing until a mass is obtained.

Insert this mixture into the hole, until it is filled to ¾. Screw the plug to the fin, insert the plug into the hole, and wait for the mixture to harden. The fin serves as a guide, so that the plug is placed in the right place.

5. Sand the area

Remove the fin, remove the screw from the plugs, and sand with a rotary sander and 80-grit paper. You have to sand the part of the plug that sticks out of the surfboard, to get a smooth appearance. Once you’ve achieved it, you can sand with increasingly fine sanding papers, from 120 to 320, to get the same aspect as the rest of the board.

And if you still do not understand, watch this video, we’ll show you everything in images:

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