Finbox repair

[McFlyfi]

I just discovered a crack around the edge of my finbox, see pics below. It is a Cobalt (eps) 9 footer, and the crack is in the trailing (aft) edge of the box. I am not so concerned about water intrusion, all of the factors for water intrusion are in my favor.

Anybody have a repair like this made? I am not happy about possibly replacing the finbox. At least I have access to the "Board Lady", the well respected guru of epoxy board repair if neccessary, her shop is only half an hour from here.





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[kitesurfer]

I am not so concerned about water intrusion, all of the factors for water intrusion are in my favor.

What factors of water intrusion could possibly be in your favour. Water getting into your board is bad.

KS

[McFlyfi]

I am not so concerned about water intrusion, all of the factors for water intrusion are in my favor.

What factors of water intrusion could possibly be in your favour. Water getting into your board is bad.

KS

Yes, water in my board is bad. I had trouble sleeping last night thinking of my brand new, now waterlogged and finbox damaged board. And how much it is going to cost me to fix. So I did what I normally do - troll the internet for an answer.

And I came up with the the Board Lady. And since I have beren lurking here for a few weeks, I figured the collective here might have some anectdotal or personal experience about fixing this type of damage, after all, these fin boxes must get blown out all the time.

According to the "Board Lady"- Typical (serious) water intrusion involves a warm board with a hole already in it. When the warm board is put into cold water, the decrease in pressure inside the board (the air inside an eps core cooling and shrinking) sucks water in through the hole. The crack ( I believe) was made during the surf session, hence, cold board/cold water, no "sucking" of water, just a possible small leak.

Even if the board was damaged on my last outing, it had two weeks to "dry out"; and water and air temps were within a couple of degrees of each other (57 water, 60 air) on the day I discovered the crack. Maximum time in the water with the damage would be around an hour, certainly enough to get enough water to some damage, but I am hopefull that water intrusion is very limited.

Also, (per Board Lady) fin box areas are typically well reinforced structurally with other materials, not just set in to the eps core. So it is likely that the damage (if in fact extensive) does not affect the eps core itself, but the finbox structure/reinforcement, which is fairly easily fixed, though not cheaply.

That makes me hopefull that the core has not been badly damaged, and why I said that the "factors were in my favor".

Anyway, I will probably just visit Ms Hollmann, and see what she says.

I will keep you updated.

Edit- See below picture for example of urethane block supporting finbox- note how eps core is not near the block. Picture linked from The Board Lady's site.

[Jimi]

never repaired an EPS board's finbox, but on my PU foam / polyester board I had a similar small crack down one side of the fin box. I only noticed it due to discolouration of the foam around the fin, so water damage was evident. I had to cut out the fiberglass over the water damaged area and fill beneath it with resin, and then re-fiberglass up to the edge of the fin box...

It's a difficult repair to make look good, and retain structural integrity.

[drowningbitbybit]

Board lady is talking rubbish.

If there's a hole in the board, water will get in. Full stop.
And once its in, it'll never be quite the same again even if you do dry it out.

Unless your Timmo - then some superglue/bluetac/biros/matches will keep water out

[tomcat360]

Well typically EPS doesn't suck as much water as polyurethane blanks. Think of it like a styrofoam coffee cup.

The board lady does some crazy stuff, but I don't have time to look around swaylocks to give you a good answer or whatever, I've got a paper due tomorrow and I started tonight..........


Good luck with whatever. From the picture it looks like there was never a really good bond with the resin around the fin box (the opaque white stuff, resin and q-cell mixture) and that's why it cracked there. The boxes probably should've been glassed over and cut out.

Who knows, I don't......I'm talking jibberish, caffieeeeneee is keeping me alive.

[miamisurfer]

Well typically EPS doesn't suck as much water as polyurethane blanks. Think of it like a styrofoam coffee cup.

Doesn't EPS suck in a lot more water than PU