Building Options

[Assocracer]

I need to make a hatch for a boat hull that I have no hatch for. What are my building options? Since I can't seem to get anyone to help with some kind of tutorial on fiberglassing I'll ask what my building options are.

[G-UNIT]

Google fiberglassing or fiberglass molds.
with out getting into detail, make a hatch out of balsa wood, aply a releasing agent like wax, ext then lay down some resin then some fg then resin then fg mat then fg cloth ect,
let dry and then seperate the balsa mold from the fg,
I'm not an expert put you should see what I mean when you see it on a you tube vid.
It does get messy and you might have to try it a few times to get the prosses down, sorry about the spelling, hope this helps.

[Assocracer]

That's kinda what I thought. I was thinking of making the mold out of styrofoam and then covering it with either aluminum foil or wax paper and gluing that down to the foam, then using a release agent over that. I figured styrofoam because the hatch isn't a nice rectangle, it's kinda funky shaped (it's an old boat)

So basically I apply some resin, then do I let that dry or do I apply some mat right away? Do I let each layer dry first or just keep adding layers? How many layers should I add? I've tried looking up stuff on you tube but it's not very helpful.

[Praxis]

The hatch doesn't need to be very strong. I would build a plug out of styrofoam, glass it, and let it dry. Clean it up and put some release agent on it. From here, you have two choices. You can either use the plug to build a reverse mold (this is the right way to do it - the outside will look cleaner) or you can just build the part on the plug and be done with it. Either way make very sure that you put a lot of release agent on your plug or you are never getting it apart.

I think you can get away with one layer of fiberglass -the hatch doesn't usually have to be very strong.

[G-UNIT]

I agree with Praxis, one or two layers of fiberglass cloth should be fine, but if you want it a little thicker lay a sheet of fiberglass mat then fiberglass cloth on top of it.

[Assocracer]

When you say glass the styrofoam, you mean just cover it in resin right?

[G-UNIT]

Well yes, if you put down a coat of resin first and let it dry what you are doing is giving it a gelcoat.
after its dry rough it up with a light sand paper and lay another thin coat of resin then apply some fg cloth then another coat of resin(just enough to soak the cloth) let it dry and if you feel its at the thickness you like seperate it from the plug/mold.
sand down the edges to proper fitment then on to paint.
oh yea wear rubber gloves, use disposable paint brushes or have a solvent to clean up your brushes, have fun and hopfully enjoy your finished project.
I will be doing the same in time on my blackjack.

[Assocracer]

So my process would be what? Make my styrofoam piece, cover it in say tin foil, then put down a release agent, then lay down a layer of resin and let it dry, then sand that lightly and put another thin coat of resin down, then lay some cloth and another coat of resin (soaking the cloth), then maybe one more layer of cloth and resin? Then let all dry and trim/sand/fill to make smooth and paint?

[G-UNIT]

By george I think you got it.
but I would rethink about the foil because I would think it would be hard to get is smooth, I would suggest some plastic wrap, you can wrap the foam tighter with no wrinkels.
use plenty or release agent, alot of paste wax or what ever.
also test the plastic with the resin to make sure it does'ent melt the plastic,

[Assocracer]

And if I wanted to use the foam for the resin, then use the resin to actually make my part (a reverse mold that was mentioned before), I would cover the foam in resin, let it dry, then remove the foam, sand it smooth, then coat it with release agent and do the same steps as before correct? Or would I lay one layer of mat down after the resin then another coat of resin?

[G-UNIT]

Take the mold and put a coating of resin over the release agent this gives you a gel coat, let dry then apply some more resin and start laying down fg cloth.
you would only use fg mat if you want it thicker.
lay down more resin then cloth ect, when dry remove the mold, the top of your hatch should be smooth, if not you can fix it by useing some light weight bondo, sand, prime, and paint.
like I said I am by no means a pro at this.
keep looking for you tube pics, just because they don't show building a hatch the proccess is still the same.
good luck, If I can help any futher I will but thats about I know.