Gelcoat questions

There seem to be a lot of knowledgable members on this site, so I wanted to ask a couple questions. I bought a Bullet bass boat with a lot of fiberglass damage to the bottom. I am in the process of repairing the glass now. When Im finished with that, I plan to re gel the entire bottom in order to bring it back to new condition. I have read a lot about "waxed" and "non waxed" gel coat. I'm not sure which I should use. Also, is the wax an additive? What grit paper do you recommend I prep the hull with?

Any help or knowledge would be greatly appreciated! Thanks in advance

 

The original gelcoat sprayed into the mould dries tacky for the fibreglass to stick to. Wax is an additive, it's paraffin wax mixed with styrene monomer.
To refinish the bottom you need to add wax to get a tack free and sandable finish. Typically you would add the wax to gelcoat and spray or brush on. Flocoat is waxed for finishing interiors and has fillers added so it can cover in one coat, not really what you want.
Start with whatever paper your quality of finish dictates to get flat then go up through the grades to about 1200 wet and dry then cut and polish. You can go finer than 1200 but its rarely worth it.
Say 120, 240, 320, 600, 800, 1200. Some people are happy to skip the 800.

 

You can get away with polishing afte #800 on the bottom. It can hardly be seen. Gelcoat is air inhibited. The wax goes to the surface during the cure and prevents it from staying tacky. I usually use Duratech Clear additive. You can then spray it like an enamel.

 

You might even stop after #240 under the WL if you are going to paint it with antifouling paint. There is a great chance to get shine through if you start with #120

 

Also, never buy waxed gel coat, always buy it with no wax and add the wax yourself.

You will normally spray a couple of coats to build it up enough so you can sand it down and not sand through in spots, so only add the wax when you know it will be the final layer.

Re-gel coating is a hassle, it's time consuming and costly, but if you want that "as-new" look and finish it's the only way to do it. Painting is much easier, but the look is different.