Re: Need HELP Repairing Surfboards!!! - I have a Video
OMG, the camera work, including the good view of the grass reminds me of younger days involving far too much tequila!
Seriously, you have many questions. I'll try to answer a few of them.
The white powder: it's a filler. You mix it into the mixed resin and place it in dents and hollows. Then you lay resin-impregnated glass over it. The powder is tiny glass beads. Don't breath them. They'll get deep in your lungs and scar them. Don't get them in your eyes. They'll scratch the cornea.
The broken tails and noses: you need to replace the missing foam and then lay resin-impregnated glass over it. You'll clean up the broken foam by cutting it off until you have reasonably good quality foam having minimal cracking or crushing. Then you cut a new piece of foam to mate to it and provide the original shape of tail or nose. You need to glue the old and new foam together. If the new piece is really large, then you use pins or dowels, as well as, glue. Then you glass over it with 2 layers of glass. One layer is not strong enough. More than 3 is too stiff. At the tail, the first layer of glass should have moderately coarse weave. The second glass layer should be pretty fine weave. The coarse gives lots of strength. The fine gives some strength and a smoother surface. At the nose, you can get away with two layers of fine weave. You'll sand between layers, especially at the edges. You need to make sure the transition from new glass to old glass is smooth. Make sure the second layer of glass is well-impregnated and that no fibers are sticking up. Fibers that stick up can be pretty sharp when the epoxy is cured.
The fins on one board that you want to move to another board: don't do it. They are not glued on. They are glassed on. When you cut them off, they'll be shorter than they should be. however, if all of this is a big experiment so that you can learn how to use resin, glass, and etc, then do it. Be very careful when cutting so you make really clean and straight cuts. I'd use a dremel with fiberglass wheel in it. Wear eye protection and do NOT breath the dust. Use resin as the glue to tack the fins to the new board. Add the glass bead filler to the resin to help fill the gaps. Then glass the fin to the board. You should lay 3 to 4 layers of glass. Each layer extends farther from the edges of the one that was laid before it. Be sure the glass is well-impregnated with resin.
The board with the big crease: you need to cut the fiberglass away to allow access to make repair. At minimum, you remove it to the point at which it is stuck well to the foam. You're going to glue the foam back together. It's ideal if you can place one, two, or more pins or dowels into the pieces that run across the break. After that, you'll apply layers of glass. You'll probably want 3 layers of glass on the top and two or three on the bottom. Each layer of glass should be larger than the previous one. Sand between layer placement. Use coarse weave glass for the first layer. Use fine weave for the last layer. Make sure the glass is well impregnated with resin.
All the broken things you showed are repairable. You need a book on fiberglass instruction. You'll spend a surprising amount of money to get glass, resin, mixing cups, etc. This is the kind of thing that is cheap-ish for guys that do a lot of this kind of thing. They'll have leftovers and remnants that can be used. but, for someone who doesn't have any of this stuff, they spend what seems like a lot. There is huge satisfaction in learning how to use these materials. And what you learn now can be used later.