Okay so i’m gonna ask what is most likely a stupid question, but I cant find a specific answer in the archives as most of the threads regarding fin plugs just go on to talk about sailboards and how the one-piece plugs are better than the x2 plugs, but here goes
1 - When repairing FCS plugs, how important is it to have the “pillar of foam” created by the H pattern you drill into the deck. I understand the purpose of this is to re-inforce the plugs against the skin of the deck so it isn’t just the foam holding it in, but why do we need the foam in the center? Is it for weight reduction/bouyancy control? The reason I ask is because I have a friends board I’m fixing and the plugs ripped out completely. It was a clean rip, so I’m left with two perfectly-routed holes where I can re-set the fin plug, but there is no foam inside them, just open holes all the way down to the deck patch. Could you not just fill the entire hole with a resin plug so that it adheres to the deck skin, minus the pillar of foam?? I know we don’t do it for impact absorbtion, as anyone who has used FCS has noticed that over time the pressure of the surfer against the deck causes the plugs to sometimes crack through the surface leaving you with those round cracks right where the resin meets the deck.
2 - if I must use pour foam to fill the holes prior to re-drilling (this is a PU board, not EPS or XPS), how do I control the density?? I know they sell it in different formulas for pre-set densities, but I also read that it expands up to 30x volume when catalized… What formula do I use to keep it from overfilling, and do I need to cover and put weight over the holes to prevent inconsistent density??
If this was my own board I would just experiment and figure it out myself, but since it’s for a friend I’d rather do it right.
Part of the problem is having the epoxy or resin start to therm and get too hot in big ol holes. The result you are trying to have enough goop in the holes to set the plugs, but not so much as to add weight or thickness....thick blobs of pure resin or epoxy will therm. EPS will melt, Poly resin will heat up and crack. Both will lead to a weak leaker repair. Plugs that come out clean were not set in the board properly in the first place. Properly set plugs usually come out of the board with huge amounts of foam and glass loss.....they just don't fall out clean.
Just do it right...Why not make a batch of mixed Q cell, DE earth, baby diaper filling, talc powder, or west system 404. Mix up the goop so it's the consistency of loose cookie dough (don't put chocolate chips of nuts in it) ..Sand flat, spray match the board, then put a glass patch over...and redrill holes....set plugs in and finish.
Yo, I wouldnt use an expanding foam to replace whats gone. Use the PU foam from a dead board or template rail off cuts. If you aint got any of that use PVC foam (Airex) if you have it, although it will look different through the deck! Shape the outside diameter of the new foam “plugette” to about that of the FCS plug minus about 6mm and bond into the board against the deck glass with a slurry of resin and glass flock. Shape the foam “plugette” so you have about 2mm of gap between the bottom of the FCS plug and the top of the foam (all with the board upside down for clarity). Then fit at per FCS instructions…
I actually have chokeloads of spare foam laying around so thats totally do-able for me… the only reason I wasn’t originally gonna take that route is because I figured since the holes I would be drilling after re-glassing would be the same diameter as the plug, that it would defeat my patch since I’d be drilling straight down trough the resin that was bonding the new foam in place, but I suppose on a proper plug installation the only place the foam is “bonded” prior to actually pouring the resn would be the deck glass.
When you say to bond the plug in with resin and glass flock, would it be feasable to use some Solarez fiberfill that already has glass fibers laced into the resin? I know it won’t UV cure concelaed in a hole so I could catalyze it with my MEKP since it’s dual-cure.
thanks again for all the help guys - you’re saving me from a headache and a ruined board for sure!
whats the puropse of the full channel instead of two small channels where the tabs go? Are these supposed to fit futures as well?? I always thought that’d be cool to try and design some kind of universal-ish finbox. Love that thread man great work
