Newbie- Options for covering foam

[SvdSinner]

I'm familiar with coating foam with carbon fiber or fiberglass to make really strong, light-weight pieces, and have done the high-tech, high-dollar, high-performance stuff in engineering school.

However, I'm interested in figuring out if there is an easier/cheaper way to coat foam to make it a bit more durable, but with no requirements of it being super strong.

The idea is that I could cut shapes out of foam with my CNC mill, and cover the shapes with -something- to allow the shapes to endure basic handling without falling apart. Example: if I made a Halloween prop, I'd like something to make it durable enough to make it through a night of Trick-or-Treating without being broken in 30 minutes.

What options do I have?

[i_am_joe]

Originally Posted by SvdSinner I'm familiar with coating foam with carbon fiber or fiberglass to make really strong, light-weight pieces, and have done the high-tech, high-dollar, high-performance stuff in engineering school. However, I'm interested in figuring out if there is an easier/cheaper way to coat foam to make it a bit more durable, but with no requirements of it being super strong. The idea is that I could cut shapes out of foam with my CNC mill, and cover the shapes with -something- to allow the shapes to endure basic handling without falling apart. Example: if I made a Halloween prop, I'd like something to make it durable enough to make it through a night of Trick-or-Treating without being broken in 30 minutes. What options do I have?

I work for a foam fabricator. We CNC Router foam all day everyday. Depending on the foam, it should be pretty durable and cut cleanly.
We manufacture case inserts that have to be very durable and withstand daily usage of items being removed and replaced in the foam.
If you can get your hands on it, a product called "Plaztazote LD45" (LD45 is the material and density) You can route this foam as soft as LD15 but not as durable and the finish is not quite as nice. If you do get some i would suggest using an up spiral cutter with at least 2 flutes to get a good clean cut.

[underthetire]

Vacuum heat sealing machine? Like the ones used in packaging.

[awerby]

I've had pretty good luck with this stuff called "Steve's FoamCoat". It does what you're talking about - sticks to the foam and consolidates the surface so it can be painted, but doesn't form a shell like a fiberglass coating. Here's a link: Steve's Coating for Styrofoam

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[slowlearner]

Thanks for the link Andrew.

[mcphill]

I bought some StyroSpray, but I haven't used it yet. What's nice is you can lay it on relatively thick, and then do some very nice finish machining on it. That gives you the lightness of foam, but the detail of a hard material...

StyroSpray Hard Coatings : Industrial Polymers

[SvdSinner]

Originally Posted by mcphill I bought some StyroSpray

Do you have a rough number on what that costs? I didn't see any costs on the website.

The two links here look pretty awesome for medium performance/medium price stuff, and give me some lower-costs ideas when fiberglass/carbon fiber just aren't needed.

Are there any other lower-cost/lower-performance coatings worth looking at?

[rcpilot82]

What about this stuff?

StyroSpray Hard Coatings : Industrial Polymers

[mcphill]

Here is the info they sent me in March of last year, so I don't know what changes to pricing may have occurred since then.

Originally Posted by StyroSpray Thank you for inquiring about our products, I will mail you a free information package which contains a coated sample of EPS foam for your evaluation. Pricing for the StyroSpray 1000 is $55.05 per gallon. It is sold in 2 gallon kits, $110.10 for the 2 gallons. We also offer a smaller 2 quart trial kit for $29.00. The price for the optional StyroPrime foam sealer is $26.97 per gallon it is also available by the quart for $8.25. Coverage for the sealer is 150 square feet per gallon. StyroSpray 1000 does not contain water or solvent, so your coverage will be much greater than other coatings you are using. A gallon of water based paint is usually about 40% water. A gallon of house paint which costs $35.00 actually costs $49.00 when you factor in the lost water which evaporates away. With StyroSpray nothing evaporates away. We do recommend a heavy coverage of 50 to 60 square feet per gallon for outdoor applications. StyroSpray is nonhazardous and nonflammable for shipping purposes, it contains no VOCs. To place an order please call us at 800-766-3832 / 713-943-8451, we accept all major credit cards. We are the direct manufacturer of this product and we ship direct to your door via UPS. click here-> http://www.industrialpolymers.com/wp...l-Data-_2_.pdf to download the StyroSpray instruction guide. I will also mail you a printed copy of the instruction guide with the sample.

[mcphill]

BRILLIANT!

[keebler303]

Coastal Enterprises also has all kinds of foams and sealers and additional materials for stufff like this.

Matt

[siam]

If you can tolerate a small amount of shrinkage, you might try going to your local Home Depot, Lowes, Ace, etc., and buy a bucket of "Ceramic Tile Adhesive" ($12/gallon). Since it's an adhesive, it sticks very well and can be easly smoothed over the foam surface to fill in all those pesky little holes. You may need to apply more then one coat and/or do a bit of finish sanding between coats to get the perfect finish, but this stuff will dry quite hard and sands and machines easily when dry. Despite the name, this stuff is NOT a Ceramic, it's actually an acrylic.

About 10 years ago I built a recumbent bicycle using epoxy, carbon & Kevlar over a foam core to make the unique frame; I used Ceramic Tile Adhesive to fill in all the open holes left in the foam after cutting and sanding it to the shape I needed.

If you need a much harder & stronger surface, you can use a mix of "Glass Bubbles" and Epoxy resin; which is what the home-built aircraft builders use. You can find Glass Bubbles (some places call them microballons) at many good fiberglass suppliers and at stores like Aircraftspruce, which sell mostly to the home-built aircraft crowd.

Good Luck.