Not a boat question :(

[Votum]

About finished with the design.

Been reading more on foam, XPS (extruded polystyrene) which is the blue foam insulation you get at home depot, is incredibly strong It's also very water resistant and easily sandable.

I am going to put the entire thing together out of 5 panels, which will have holes drilled into all of the support areas and wooden dowels glued into the holes to hold the foam together.

After its together I will cut the "hatch" out of the foam, and make some sort of hinge for it, also trim out some channels so I can lay weatherstripping into the glassed one.

Now I think I am getting from you guys that elmers wood glue is a suitable barrier to put on the xps to enable me to use Polyester resin, right?

I'll end up doing a test first to see how thick I need to lay the glue on it.

Also, is this a stupid idea:

Leaving the foam on the top. The foam will be sanded and shaped, glass will be laid over it, and then I am thinking of laying glass on the inside of the top as well...is this kosher or the dumbest idea ever? Will the foam melt in the sun or degrade over time?

Thanks for being so nice by the way!

[Votum]

http://www.rqriley.com/frp-foam.htm

This is exactly what I am going to do

Using XPS though...Man I am excited. Designs are finished, will upload when I get off work!

Originally Posted by Votum

Water resistance is the least property you need!

Why so complicated? Test the foam by brushing some styrol (thinner) on it. Wait if it disappears or not.
If it does not, you must not "prevent" it.

I'll end up doing a test first to see how thick I need to lay the glue on it.

Also, is this a stupid idea:

Leaving the foam on the top. The foam will be sanded and shaped, glass will be laid over it, and then I am thinking of laying glass on the inside of the top as well...is this kosher or the dumbest idea ever? Will the foam melt in the sun or degrade over time?

Thanks for being so nice by the way!

You cannot leave the foam inside. It is too brittle to stay intact. Vibration will soon make powder of it.

Regards
Richard

[Votum]

Here are my completed plans

Looks nice.

The Latex paint will probably not work! And a screwed layup is sure more costly than getting the right foam and test it!

[hoytedow]

You can get this painted to match auto paint. Or you can get matching aerosol cans at a parts place. Avoid latex and use a good oil based primer.

[hoytedow]

And apex is right. It looks nice. Well done and thanks for your service.

[Votum]

Thanks guys. I am always looking for tips OK so no latex...I think I am going to spend some time searching for Urethane foam when I get home. Sounds like that is the best option. Do they make it dense enough for my needs? How much does a 4x8 sheet normally cost? The only stuff I can find online is mattress foam

No foam core...what if its urethane? Should I not use any core at all? I'm sorry I'm being such a hassle Trying to get every single detail worked out in my head before I even start buying stuff lol. I will test whatever I get though because I've never done fiber before. Done plenty of bondo so I think the basic idea is the same.

Paint for the outside is going to be krylon camo olive drab

[Votum]

Oh and how do those mesaurements look as far as strength goes? I know flat spots reduce strength in fiberglass, I was thinking of doing a layer of 1.5oz mat on top of the foam, then a layer of maybe 15 or 20oz bidirectional cloth, then another layer of mat as the finishing layer. That should be about 1/2" of fiberglass or a little more I think. It doesnt need to support any weight, since the windows will be whatever weather resistant and scratch resistant plastic I can find

[hoytedow]

You will probably need to buttress where I placed the green lines. Otherwise I have no substantive criticism.

Originally Posted by Votum

Oh and how do those mesaurements look as far as strength goes? I know flat spots reduce strength in fiberglass, I was thinking of doing a layer of 1.5oz mat on top of the foam, then a layer of maybe 15 or 20oz bidirectional cloth, then another layer of mat as the finishing layer. That should be about 1/2" of fiberglass or a little more I think. It doesnt need to support any weight, since the windows will be whatever weather resistant and scratch resistant plastic I can find

A litttle less is suffficient.

The quality of your layup is important. Half an inch of glass is too much.
A layup as described is far less than that, and sure suficcient.

Richard