Can I make my own foam core?

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steeps
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Can I make my own foam core?

Post by steeps » Thu Jun 03, 2004 11:13 am

Is it possible to make foam panels using 2 part foam and molds? If so, what type foam is most appropriate and how would you derive the thickness of the panels based on the recommended plywood for the same part? Or do I just have too much to think about on my drive to work in the morning :doh:

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Post by tech_support » Thu Jun 03, 2004 11:51 am

Please start with a small boat and send us pictures. "Yikes" is all I can say.

P.S. When you test it, dont go too far from shore.

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Post by tech_support » Thu Jun 03, 2004 11:58 am

I think I was being too much of a smart a$$, sorry.

You can get a lot of information on the physical properties of boat building foam over the web. This type of foam is VERY different than what you are talking about.

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Noone is more of a smart A$$ than me.

Post by steeps » Thu Jun 03, 2004 1:56 pm

The more I read about foam today the worse the idea sounds. The idea started when I took a tour of a boat building factory. They stressed the strength of the boat due to all the injected foam. So I started to think, why can't I build a core out of this foam and fiberglass over it, surely my boat made of higher density foam and epoxy would be stronger than their's :wink: . Perhaps I'll try it with the cheap canoe and give it to my neighbor as a gift. He's a big guy and would make a nice guinee pig.

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Post by tech_support » Thu Jun 03, 2004 3:36 pm

That sounds like a good idea. Let us all know how it works. you might think about doing a few test panel, then you can see what sort of strength you get.

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Post by ks8 » Thu Jun 03, 2004 3:41 pm

I bet someone has already built a nice canoe with foam sandwich. But it is foam panels that are used, not injected foam. D4's also have been built of foam panels. Surf around the web. But be careful with injected foam. Of course foam panels at some point were probably injected during their manufacture, but the foam is spec'd quite different from buoancy foam! Are ready to tool up for that sort of operation???

If I missed something, sorry. I just glanced the post quick and typed.

sincerely,
ks

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Post by tech_support » Thu Jun 03, 2004 3:55 pm

I have seen on the web somewhere a builder who used some cheap foam, and the fiberglass just peeled right off after the cure. For the best results, you need something that is designed to be laminated for structural use.

I am working on finding a cheaper foam core, one that could be used for non-structural applications like consoles, seats, doors, interiors, etc... I am supposed to get some samples next week, and I will give them a test.

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Not cost effective

Post by steeps » Thu Jun 03, 2004 4:23 pm

I was looking at using 8lb 2 part Urethane foam, it has similair properties to Divinycell H130. The problem becomes that at $180.00 for 10cu', I would only be able to produce about 1.5 2" 4X8 sheets. I could drop to 2lb foam and lower cost but the shear strenght drops from 130psi to 30psi along with other properties.

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Post by MikeS » Thu Jun 03, 2004 6:09 pm

Plywood is a known quantity and cheap compared to an experimental foam boat. If the 2-part foam was usable as a core all the boat manufacturers would use it. The containers specifically read "Flotation Foam." :wink:

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Post by steeps » Thu Jun 03, 2004 6:28 pm

Not to beet a dead horse, but the foam I am speaking of is not just for floatation(not even labeled for foatation). Depending on the lb, it can be used as structural support, castings, etc. When you get in the realm of 16lb foam it is hard as a rock, you can hit it with a hammer and not break it. With this density foam you would have to use a mold becuase it does not bend. I am well aware of the availability of plywood, but if it were perfect for every situation foam cores would never have been invented in the 1st place.

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