FCS 2 replacement, I have a plan

About 2 years ago I shaped a nice 7 6 midlength kinda thing. I only just had it sanded as it had been sitting after the hot coat for 18 months at least, I had other projects and then a significant shoulder injury that resulted in surgery just before Christmas

My wife did some nice artwork with watered down acrylic water based paints on the foam.
But I had a few too many beers when installing the fcs 2 fin boxes I salvaged from a broken DHD. ( good thing I’ve been on the wagon for nearly a year now)

I managed to route out the hole with the jig on the wrong line, DUUUUH

I ended up just routing the correct spot and having the hole larger than the fin plug on stringer side of the hole. When setting the boxes, I had my dummy fins in the resin in the hole ant all the tape in place, cant angles set and all was good. I left the shed to do other stuff. Came back when the resin had set and the box had slipped towards the stringer so when a fin is in the box it has a little extra toe in and the cant is slightly different from the matching front quad on the other side.

In all honesty my plan is to surf it as it is for a bit but replace the FCS 2 plug at a later date.

BUUUT the plan for that.
the damn spring rod…

  1. Get the cutting wheel on the Dremel and cut into the box vertically either side of the spring and get out the metal rod.
  2. Sand the surface as flat as I can, set up the FCS 2 jig (in the correct spot this time). Tape the crap out it so it stays in the same spot.
  3. Set the router shallow and route out the remainder of the spring less fin plug in 3-4 passes. There will be a tiny sliver of the old plug still set in the board. Then I can set a new plug into the hole and cover with 2 layers of cloth and sand etc.
  4. Then maybe do a little bit of posca paints to cover the slither of old wrongly installed fin plug.

It may seem over thinking it but most repairers I have spoken to tend to try to manually leaver out the plug after cutting the glass around the plug, this will just make a massive mess. Hence the over thinking…


Yeah that should work, I’ve seen youtube videos doing exactly that. I’ve also seen videos routing out a larger patch then setting a foam dutchman repair. Then routing out for the fin plug.

I think grabbbing the pin and prying the plug out makes more sense when the fin plug is already loose, which is often the case.

You should watch some YouTube videos on this. Common mistakes I see are 1) making more work than necessary by routing the foam all around the plug, in those cases where just a little thickened resin is all that’s needed, and 2) patching in with cheap low density foam to install the fin plug into. Yeah there’s a lot of goofballs on YouTube, but I still learn (even if its what not to do) & get ideas even from those guys.

My inclination would be to route out the old fin plugs.
Add balsa inserts. Then instal new fin plugs in the balsa inserts.
IMO it would look much nicer than multiple patch jobs.
Just my $0.02.

Balsa would be a good strong patch to mount fins in. But since its often just one fin plug being replaced, might kinda stand out. Almost have to do 2 if going back with balsa.

Yep. If I was building for aesthetics, I think I would do that.
Might be easier in the long run just to remove the plugs on both sides.

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What you describe will work.

I’d probably do it slightly different just for optics.

I would route out the old plug.
Make a decent foam insert (blank cutoff works good). Then route the new plug. The little remaining foam halo on one side will almost be invisible.

The foam insert can be shaped by hand. Another way is to tape a piece of foam to a spare plug with double sided tape and run a copy router bit on it. With the spare plug as a jig. I did that and ended up with a very snug fitting foam insert without gaps. I used a router table and held the plug with a dummy fin inserted. Watch your fingers.

Concerning the metal pin:
The Dremel will be fine. Probably the safest way.

Another neat way of doing it is a router jig which spares out the area of the pin. You’ll end up with 1/4 of the plug left after routing. The remaining piece comes out easily. But there’s a little chance of tearing some foam with the remaining piece.

Brad Rochefort once showed some prototype jig. But it’s quite easy to make a jig from plywood or whatever you got.
Just make sure the jig doesn’t move around while routing.

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