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Styrofoam Answered

Does anyone know how to make styrofoam. I am tring to build a small boat and I need a lot of this stuff



10 years ago

Different types of foam (but probably not styrofoam) are used as a core material in composites for all types of craft, including 99% of surfboards. It's a tried-and-true technique. Even the pink construction-grade foam would be preferable to styro. Beware that the chemical composition of some resins will eat polystyrene foam. Polyester resins, the type found in automotive fiberglass kits will do that. Real epoxy resins (marine epoxy) are usually safe.

Beware that the chemical composition of some resins will eat polystyrene foam.

and a number of solvents LOL I found this out many moons ago when I made a replica of our solar system with polystyrene and then went to paint them with spray paint.....and they melted *sob*

now you made me sad too! stupid empathy.

At the time I was surprised (I was pretty young), and then sad because I wasn't going to be able to get "more". Most of the planets ended up looking like asteroids....all misshapen and stuff. :-)

I was not sad about it, I learned valuable lessons from that, helped me want to explore chemistry a bit more :-)

Ooof. No fun, that. (I have seen designers use this to advantage--make the fiber/resin shell with a safe resin, then dissolve the foam inner (male) mold with solvent. The shell only remains, so it's even lighter...)

once the solvent dried, the polystyrene hardened and became quite rigid.

Making Styrofoam involves putting polystyrene (a petroleum derivative) under tremendous pressure, resulting in very squished particles that are shaped into planks, last forever, and repel water, according to Dow. Do you mean rather, Expanded Polystyrene (EPS) ? EPS, is made by heating polystyrene particles, pouring them into molds, and injecting them with steam. Meat trays, coffee cups, picnic coolers, and their ilk are all made from EPS, never from Styrofoam.

I thought "Styrofoam" was a brand name for a particular company's EPS, similar to the way "plexiglass" is a particular Acrylic sheet...

does plexiglass shatter like glass? I always get mad at movies such as I am legend whenever plexiglass cracks and sounds like breaking glass, etc.

plexiglass cracks easily, but does not shatter like glass. it can still cut you though. it does make a loud crack as it breaks, and it scratches millions of times easier than glass (for a good use of this ability, go here)

I've never seen it shatter, just crack and break... Doesn't mean that it couldn't though...

If it gets old it can. It shouldn't shatter like "plain old glass" normally though. Although it is disturbing to see "automobile glass" shatter like picture frame glass on "movie cars and trucks" too.

According to my sources Styrofoam ® is a registered trademark for a form of polystyrene product.

Take a look at marine foam. I don't know if regular styrofoam or other rigid foam insulation type stuff at Home Depot is good in sea/fresh water for a boat. I guess that is why the marine rated stuff is expensive. Is this a wood boat or fiberglass one?

The boat is wooden. I am using the foam as an extra buoyancy mesure ya know over kill

Handi-foam, from the description is a Pour-In-Place Foam multi-purpose slow-rise polyurethane foam, rather then a polystyrene foam. I am not sure what that means in the case of use except that polystyrene is normally sold in solid form.

If you have a custom form or mold or if you are using "sandwich' technology to build the shell (wood/fiberglass+foam+wood/fiberglass) the liquid foam will expand to fill the inner core and glue up the outer layers into a very strong piece. Even houses are built using poly-isosomething foam sandwiched with plywood/OSB. The slow-rise is to keep the pressure of the foam from blowing out the form when it expands. So, if you are using those foams to fill gaps in your house, make sure you get the right kind as not to warp out the window or door frames.

Please do NOT make a boat out of styrofoam, it crumbs and becomes waterlogged, you'll spend more time building the boat than the boat will last on the water.

Not if he coats it in a waterproof marine sealant. Even if he did though, the idea of a Styrofoam boat is not very practical anyway... Without proper ballast it would capsize, not to mention be extremely light.

Only if he used a non solvent based sealant, and if he could afford that he wouldn't be making a boat out of Styrofoam. Regardless, sealed or not, the Styrofoam core would quickly disintegrate under flexure stresses.


10 years ago

just come to have a look

Bran is correct. It is not possible to make Styrofoam without commercial equipment and materials. You are much better off buying model styrofoam from your local hobby shop or home depot (or other similar store)


10 years ago

Making it would be a bit difficult - it might be easier to start with a different kind of foam and shave it to shape and size.

you can't really make it... I think