Quad Fin Buckle? To fix or not to fix.

Got a new stick - quad fin set-up on a Flying Pig… as far as the board goes I’m still getting used to it but I’m thinking I like riding this shape as a Tri better, which I kinda knew would be the case from the get go but I’m probably gonna put a 5th box in.

Anyhow, after only my second session - which was basically an entire day so multiple sessions in punchy head high barrels - I noticed that it seems it wanted to buckle in front of the fins, basically all the way across. However I can’t figure out if its just the hot/gloss coat that has flexed and cracked because its not the actual fiberglass, there is no foam showing even though it looks like it in the pictures. There are minor stress cracks in front of each trailer fin as well. Regardless the stress cracks are pretty serious and I want to do something about it before theres a more serious problem, and I tend to lean towards punchy surf, even on boards like this so I dont want to buckle it, or have it snap. I’m pretty bummed I already have to mess with the board, esp in such a critical area, I’d really like to leave it alone, or simply seal it but I don’t want to break it either. So my question is what should I do? Do I need to sand down and re-glass the large area, rail to rail, around it + around fin boxes?




And to reiterate… the areas where it looks like it cracks to the foam isnt actually the foam it seems to just be the laminate coat. The hot coat chips right off… I’m really confused I’ve seen stress cracks but never anything like this.

Anyone??

Just looks like a standard stress fracture to me. Here are a few reasons why it could have happened:

  1. The tail of your board flexes a bunch, if you notice it’s right in front of the future boxes, which do not flex.

  2. Any excess of resin build up will fracture before the cloth buckles. It won’t always just flake off right away. Even though the board was sanded I’m sure it has concaves and resin tends to settle in those areas and if the sander didn’t hit it hard enough then it will crack, especially in those high stress areas.

Totally an easy fix, and worth it. Got more info if you need it. Hope this helps a bit.

 

 

Thanks. Yeah I’m def planning on fixing I’m just not sure if I should just sand it lightly and throw another hot-coat over the area (wont it just crack again??) or if I should add some more strength and re-glass the area. I think I’m just gonna sand lightly and seal it up… I just hope it doesnt buckle doing (or attempting) a reverse or something of the sort with a lot of stress to that area. I have a tendency as well to buckle boards on my inside rail in front of the fins simply doing hard bottom turns… 

Okay, first off - hot coat is like hard candy: more and thicker may initially stiffen it some, but get past that point and you only get bigger pieces cracking off.

Do sand, lightly. You just want to make enough 'tooth' in the hotcoat so it'll hold new glass well. Don't sand into the glass at all.

Do add glass. You'll note that the cracking is right at the ends of the markedly stiffer-than-the-rest-of-it fin boxes? So the board wants to flex lots more back there, but the fin boxes ain't letting it and your hotcoat and gloss are breaking up. So, stiffen up the area in general, add glass. You'll lose some flex in the tail, but hey, that's what this problem is all about.

Do not, however, do it as a simple band across the board or around the board. I'd suggest a kinda diamond shaped forward end to this 'stress patch' well forward of the fin boxes and taking it full width and right to the tail from a bit in front of the fin boxes all the way back. Reason being that if you have a sharp change in the stiffness of the board that goes rail to rail, that's where it'll start to crack and likely break the next time. The diamond-type end will hopefully spread that transition out some.

hope that's of use

doc...