I have a slightly displaced fin box, the box itself is ok, and normally if I get a few cracks around the box, I would push in some epoxy and then glass around the fin. I also get that if the box itself is broken it needs to come out and be replaced. I repair plenty of cracks and holes using epoxy with or without filler. Can anyone tell me if it is possible to realign the fin without pulling it out totally and making the whole exercise bigger than be hour. My thinking is to drill down the slightly depressed side to get enough leverage to straighten it. I will tape the fin to the rails to hold it up, inject/drip epoxy down the side, let it set back into straight position, use epoxy bog for any holes in foam and between foam and fin box, then glass with clear epoxy as usual. The foam is not badly damaged at surface but I am guessing there must be some crushed foam under the base of fin box, fin box is only off by 1-2mm. Note this is a surfclub paddle board, not a surfboard so there is no stringer on underside, not sure if there is a stringer imbedded under the fin box and that is why I do not want to pull it all out.
Any advice greatly appreciated.

sorry there is no short cut with epoxy and eps it has to come outusing a hacksaw blade you should be able to cut fairly cleanly around the box then putting the fin back in remove with a bit of force

I've had good success repairing a wobbly Futures box in an expensive EPS epoxy board by injecting resin into the loose foam around the fin box.

THere was no compression of the glass around the fin box on my board, though the glass around the box did move, so success depends on how badly your fin box has damaged the glass.

I very carefully drilled several holes down from the deck to the sides of the fin box. I then used a piece of wire to enlarge the void around the box. I injected resin into the holes and wobbled the fin back and forth to get the resin to flood all of the voids. I then secured the fin at the right angle and let the epoxy set. The voids extended from the fin box up to the deck so the box is now secured to both the top and bottom of the board.

I was told I would have to have the box removed. Because of the colours on the board removing the box would have been a complex repair job. My local repairer didn't want to touch it.

This repair was to a kite surfboard which places large loads on the fins. I've used it at Margies, the bombie and at gnaraloo over the last 12 months or more with no movement in the box. Personally I think this is stronger than the typical Futures setup which only relies on the bottom layer of glass to hold the box in place.

So if the bottom glass isn't too rooted and you don't mind a carefulness and fiddly repair, it can be done.

Thanks for the responses. I fixed another fin box where the fin was easy to realign and filled epoxy down the sides. This fix worked OK, as its a surfclub board, there is enough strength for normal use and if they smash into another board it will re-break either away.
My issue with this one is the fact the box is slightly off centre, if it was straight I would be OK filling with epoxy.

Katana, would you recommend that every fin box break neds to have the box taken out, a foam block inserted and the box reset, or would you sometimes simply epoxy around the box and leave it in place?

Hunter, did you have much damage to the eps around your fin, I have very little, however if I pull out the box, then I will have to put another eps block in place etc, sounds like quite a mission. If I could get my box to realign without damaging too much of the glass attachment, surely this would allow me to fix it without pulling the whole thing out?

I assume the eps can be glued in with wood glue as well as epoxy?

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Tmb said..

Thanks for the responses. I fixed another fin box where the fin was easy to realign and filled epoxy down the sides. This fix worked OK, as its a surfclub board, there is enough strength for normal use and if they smash into another board it will re-break either away.
My issue with this one is the fact the box is slightly off centre, if it was straight I would be OK filling with epoxy.

Katana, would you recommend that every fin box break neds to have the box taken out, a foam block inserted and the box reset, or would you sometimes simply epoxy around the box and leave it in place?

Hunter, did you have much damage to the eps around your fin, I have very little, however if I pull out the box, then I will have to put another eps block in place etc, sounds like quite a mission. If I could get my box to realign without damaging too much of the glass attachment, surely this would allow me to fix it without pulling the whole thing out?

I assume the eps can be glued in with wood glue as well as epoxy?

I found the main issue with injecting is the moisture under the box will not allow the epoxy to set properly

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Tmb said..

Hunter, did you have much damage to the eps around your fin, I have very little, however if I pull out the box, then I will have to put another eps block in place etc, sounds like quite a mission. If I could get my box to realign without damaging too much of the glass attachment, surely this would allow me to fix it without pulling the whole thing out?

I assume the eps can be glued in with wood glue as well as epoxy?

Katana's right, moisture can be a problem. I don't mind spending time doing repairs on my boards so with bad EPS dings I've followed the advice of windsurfers - washed out the ding area with fresh water to remove the salt, then left the board in the sun to make sure it's good and dry and then hooked it up to a vacuum pump to create and airflow through the board to dry out anything left inside. Gotta be careful though - apparently if the pressure gets too high it can collapse the board.

Regarding damage to the foam - I have also done this repair to a fin box which was badly compressed into the board. Just wrestled the fin back into place and filled around it with resin. Not pretty though and probably not the sort of repair that a pro like Katana would contemplate.

Wood glue??? WTF, It's a surfboard. If you mean araldite - that's a desperate act, but I think I have actually done that once. I use West Systems epoxy resin now. Standard advice is to test any glue or resin first to make sure it doesn't dissolve the foam. Then if you're not concerned about aesthetics - go for it.

Thanks Katana and Hunter. he previous fin break that I fixed was caused by the board being stood up and breaking on the ground, I do not expect moisture to be an issue as the board came straight out after a collision with another board, however I guess water gets everywhere fast, however it is not very open damage and the foam is in good shape with no or little depth (except that the fin itself has shifted a couple of degrees.
If I break out the box and dry cavity, I will need to shape some eps, wedge it in, position the fin, fill with epoxy. I suppose this is not much more work than trying to align it without total removal.

My only concern is damaging something when I wrench the box off its base. I am not concerned with aesthetics, just need to get board back into the water, no ambition to do a job of work like Katana would do.

I had heard other people say they used wood glue to fix the eps, however my preference is using epoxy, I use the Epiglas epoxy which seems similar to West.

As an aside its a Katana board so if I mes it up I will be going back cap in hand to get Katana to do a proper job