Painting polystyrene(pink insulation) foam suggestions?

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John Murphy
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Painting polystyrene(pink insulation) foam suggestions?

Post by John Murphy »


I am wondering what primer and finish would work best on polystyrene.

I am quoting a job that is essentially a giant puzzle made from multiple layers of polystyrene foam. It will be 7' in diameter and 18" thick. The idea is to have a person assemble the simple puzzle in a given time.

I am concerned about the finish holding up over repeated handling. I have considered the "abracadabra Smooth" product, but I have never used this before, and I'm not sure I want to test it out on this size of a project.

I know Gerry from Quebec showed me something when he last visited, but it's been so long, I can't remember what he called it.

If you have any suggestions, it would be greatly appreciated.


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Re: Painting polystyrene(pink insulation) foam suggestions?

Post by rej »

you might look at getting some styrospray. it can be brushed on.
i have used it on the pink foam with good results.
i have purchased abracadabra before, it is very expensive in my opinion. it works well, i'll give them that much. but wow, it was alot of money.

Gerry Perrault
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Re: Painting polystyrene(pink insulation) foam suggestions?

Post by Gerry Perrault »

Hi John
This is Gerry from Granby Quebec,i will try to go back at Ontario Meeting, if i am not too loaded. I really have enjoyed that meeting with all the other CNC guys.
To come back to the subject, here is the name of the company that sells the product that you need for that job.:Polymeres Technologies , 1-866-799-3058 (
Product name is Techno Lam is a mixture of 100grams (a) mixed to 13 grams (b),you will need a scale for the right quantities it is specialy made for polystirene.
p.s.: they speak english
there is also another product which is more expensive at the beginning but after ward is quite reasonable it is called
Volatile First you have to buy the special gun and dual cartridge in boxes of 6.
If you intend to do a lot of stirene , i think it is a good investment.
you shoot the product and prime after ward while tacky .
hope it is helping you,see you John. Gerry
I rather be the leader,than the follower

John Murphy
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Re: Painting polystyrene(pink insulation) foam suggestions?

Post by John Murphy »

Thanks Gerry.

Hope to see you in October!


Re: Painting polystyrene(pink insulation) foam suggestions?

Post by GraClay »

John, normally I would use water-based acrylic paint starting with two coats undercoat then at least two of gloss finish. I'd normally seal it first with a waterbased clear
but that is a personal preference & have access to the clear.
As yours is to be handled and you want something tougher you could use two or three coats EPOXY resin mixed with a thixotropic powder to give it some guts.
You would buy that from a fibreglass supplier. Make the coats thick and play with the brush to pickup runs or sags. Then paint it with undercoat & finish colour.
Note: do not use polyester resin as it will melt the polystyrene.
There are companies that will spray a hardcoat to styrene when it used for architectural pieces on buildings. If your budget allows it, that would be the best method.

You can actually use alkyd based enamels (turps based to the layman) on stryene however it must be fresh from the can and not previoulsy diluted.
Test first if going down that road.


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Re: Painting polystyrene(pink insulation) foam suggestions?

Post by oxenham1 »

Hi John,
In this case, you need a serious hardcoat as people will be handling the pieces. We use a few products, some are more expensive, some are easy to use. Styro-spray is from Industrial Poymers from Texas and is a fairly affordable 2 part urethane coating which can be sprayed on with a regular hopper style gun. The beauty of this product is it sets in approx. 30 min and is hard enough to sand or machine overnight. Plus you get the added benefit of being able to put it in a container overnight WITHOUT it hardening up which is quite amazing for a 2 part urethane coating. The 2nd (and the best) is the easy spray system from Smooth-on. VERY EXPENSIVE when you include the special gun. 6 sqft at .100" thick will run around $120.00 per cartridge. But you can sand it approximately 3 minutes after you spray it. This is the best choice for fire proofing and extended outdoor use. We get our Smoothon stuff from Sculpture Supply in Toronto.
And finally you could use FOAMCOAT from Rosco in Toronto. Here is the blurb from their site:

FOAMCOAT is a non-toxic, water based coating for styrofoam and polystyrene foam, as well as other surfaces. It provides a hard, durable finish that resists chipping and cracking, yet can be sanded smooth or carved to add detailing. FOAMCOAT can be used on a wide variety of surfaces including foam, primed wood, concrete block, primed fiberglass, paper maché, muslin and many other materials. FOAMCOAT is fully compatible with all Roscopaints used either as tints or as surface coatings. FOAMCOAT is inherently flame retardant and water resistant.

APPLICATION: Apply by brush, roller, or hopper spray gun depending on the desired finish. The thickness of the coating is determined by the application. When coating over fine details, use successive thin coats to build up a protective layer without obscuring the details. For an extra smooth finish without sanding, smooth the coated surface with a wet sponge just before the FOAMCOAT has set completely.

SUGGESTED USE: Excellent for use as a protective coating for all types of foam projects. Especially useful on foam scenery or props that receive physical abuse or need to last for extended tours. It can also be used as a texturing agent that is much more durable than plaster or joint compound.

I hope this helps, it took us a while to find these products over the years. Please feel free to contact me if you need any help with your project!
The below images were all coated with Styro-spray.
styro trees props.jpg

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