One side of the box/glass is in perfect shape, but the other side cracked and dug into the foam but is solid. I'm happy with the fin/placement so I thought instead of ripping the box out and replacing it, I could just glass the fin in - make it nice so it looks like a glass-on. Anything wrong with doing that structurally?
More savvy shapers than me will be along shortly, but off the top of my head, I'd think it would be better to replace the box. You say "ripping out the box", but I would router it out carefully, and install a new one. Like you, I have my doubts about how sound it would be structurally to glass the fin into a cracked box. The point of attachment needs to be strong, and you've got a weak spot right there. Just my two cents!
Howzit northeast, Glassing it in is just a hack job and if the fin is in the wrong place you can't do a thing about it pus you have ruined the fin.Take out the old bad box and put in a new one, it's not that hard to do and you have a new box instead of a mess. Aloha,Kokua
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One side of the box/glass is in perfect shape, but the other side cracked and dug into the foam but is solid. I'm happy with the fin/placement so I thought instead of ripping the box out and replacing it, I could just glass the fin in - make it nice so it looks like a glass-on. Anything wrong with doing that structurally?
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Good luck!
Is it a plastic fin?
Back in the day we were taught...
"...If you don't have time to do it right the first time....When will you have time to do it over"......
I'm the guy you call after you try to fix it yourself with some half baked plan. I can do it right.
Kokua and Huckleberry are Master Craftsman......Listen to the Masters....
Ray
Save your router bit, and some money.... Depending on the overall condition of the board and your priorities it might be fine to glass the fin in to the broken box.
Decide where you want the fin, make sure it's vertical then mask off the bottom and pour laminating resin and some shredded glass in the box slot and any voids where the foam is crushed. Once that's solid, add multiple layers of glass up the sides of the fin and over the box on to the bottom of the board just like you were glassing on a fin. Hot coat, sand and gloss if you like. The 'glass-on' technique will be plenty strong if you use enough glass. My typical glass-on installations have 10 layers or so per side plus some strands of fin rope or shredded cloth.
If anything, having the fin down inside of the box before glassing it in will make it structurally stronger than if the fin was just tacked on to the bottom with hot glue or whatever before glassing.
Trust me, it's been done thousands of times. I have a board that I did it to about 25 years ago and the fin is solid as can be.
I glassed it in yesterday and it turned out good. It was a singlefin center fin box on a shortboard. I used the method described by Thrailkill instead of roving - my patches were 4 layers of 6oz. per side on the bias. The voids in the fin box I filled with some scrap foam and glassed over. It could use another hotcoat so I can sand it smooth and pretty but I’ll need better weather, right now tthough it’s rock solid and rideable. My main priority was to be able to do it myself with what I had to get it in the water for hopefully the next 3 days of surf! Thanks for the comments and suggestions, esp the step by step from jmellor.
Howzit northeast, Use some thing like a 1/4" straight router bit and run it right down the center of the box from end to end and make sure you have gone deep enogh to go through the bottom of he box. This should make it easy to pop the damaged box out and then just install a new one. This way you don't have chunks of plastic flying around the inside of where the box was and messing up the foam. Aloha,Kokua
Hello Northeast.jd ,
I'm not dis-agreeing with any of the comments so far. You left out a lot of information and you did not post a photo.
Long Board or short board?
What type of box? (Brand)
Plastic fin?
Surftech? Boardworks?
EPS/Poly?
Surftechs are painted on the outside. Polyester resin eats EPS foam....Plastic fins do not bond well with resin...Surfers do not understand sanding.....Why go to all the trouble of glassing when maybe you just need to reinforce the box.....
I could be totally out of line.Take your time ...plan out your project....
Stingray