Need a little help. I'm in the process of replacing the fuel tank in my SS250 Switzer. I cut the floor outside the stringers to remove tank. In the front there is plywood under the floor that the new section of floor will sit on. Towards the back I will do the same. My question is I am going to use a new sheet of plywood to cover the tank. If there are any gaps on the seam around my cut how should I fill it? Or is that even necessary. I am also going to put glass mat over the floor probably going about 6" out past the seam. Also what products would be best for this project.

Thanks Scott.

Off topic and not quite sure this will work but I am parting out a baja 280 sport and have the removeable piece that fits over the tank that I no not need. If you are interested giver you dimensions and I will seeing it works.

Thanks for the offer but just want to cover tank and not worry about it.

Just mix up some resin and filler. You can use just about anything for something like that, cabosil, high density filler, even saw dust will work. Smooth it level and lay your glass over top of it.

Any decent polyester resin will be fine for that repair.

I was going to fill the joint in first and let that set and then sand it down and then put mat over the whole floor to tie it all together. Would that be correct way to do it? Also what is the difference between epoxy resins and polyester resins

The difference between epoxy and poly is price, strength and stench, among others.

Epoxy is more expensive, but stronger secondary bond and little to no smell but you still do not want to get the hardener on your bare skin.

The poly is what your boat was made with, less expensive, and doesn't have quite the secondary bond strenght that epoxy does. But in your case, all you are doing is trying to seal things up, you don't really need the strength of epoxy or vinyl.

There is any number of ways you can fill the gap in. You can fill it, sand it, then lay your glass over it. If you use poly you'll need to add surfacing wax so it cures completely and you can sand it, unless you are using a resin that already has the wax in it. If you don't it will stay 'green' and will gum up your sanding discs.

I would fill it and lay the glass over in one step, so that way I didn't have to sand it in between and it would be done in one shot.