I’ve got a broken lonboard finbox I’m reparing. I dug the finbox out and found that they only used resin to put the box in, no cloth. I believe that’s the case anyway. Check out the black chunks ontop of the board in the first picture. I can’t find any fibers in them.
Whatever, boxes break, the glass job is absolutely beautiful and strong otherwise. My question is, the tail on this thing is pretty thin. I’ve cleaned out the funk from the old box and resin, and this his how much of the box is sticking out.
The tab at the front is about 1/8th off the glass. The tab in the back is 1/4 inch off the box. I’m going to clean it out again and try to get it deeper, but I don’t think this thing could have been to the tabs when it was installed.
My question is how much of the box below the tabs can I grind off?
I’d try and go deeper in to the foam. Shine a light under the board so you can get a better idea of how much foam you have to work with. Just a little high spot on the stringer or a chunk of leftover resin will prevent your box from sitting right. I’ve done box holes right down to the deck glass - a little white pigment in your resin mix and it will hardly show. Ideally, you won’t have to grind very far past the tabs. The base of your fin will stick out if you grind off too much.
Thanks John. I’ll get back in there and make sure nothing is keeping the box up above where it originally was. I really don’t want to go deeper than the original box installation. There is prolly a half inch of slot area below the tabs that holds the fin in place horizontally.
If I can’t get it down much further though do you think it’s ok to grind away about 1/8th of an inch below the tabs?
Maybe what I’m looking at is a resin dam above the tabs? It looks like a lot of box sticking out but if the box has one of those resin dams or covered slot, maybe it isn’t as high as it looks.
1/8" isn’t that much to grind off but flush would be better.
That sounds like a pro tip. I’ve only insatalled one on my first board. No bubbles, but maybe I got lucky.
What cardiffchris says makes sense though, without the tabs, how would you keep it level? If you have a well routed hole to set it in it might not be a problem.
Boxes didn’t used to come with tabs or the resin dam. Put a fin in, tape all around the base and the top of the box and set it in. Eyeball it until you’re sure it’s straight then tape it from the tip to the rails. Double check and drive yourself crazy wondering if it’s really straight - or are your eyes playing tricks on you?
