# Primer/paint for styrofoam



## buccsfan64

Im starting a 4x8 layout using a 4x8 sheet of the white styrofoam insulation from Home Depot. I peeled off the plastic coating. I was thinking I would coat it with latex primer before starting so later any other color would stick. Will primer adhere to the white foam board or will it peel up months or years down the line? I also have some KILZ primer available if thats better but KILZ said it might not stick. 

thansk.


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## Gansett

I'm no means an expert but I think you have the wrong stuff. You want the pink or blue foam board.


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## gunrunnerjohn

You don't want the white stuff, pink or blue structural foam. That is way too soft.


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## Reckers

Buccsfan64, welcome to the forum! Let me start by suggesting that, if you're using the white styrofoam that consists of a zillion little round pellets all bonded together into a sheet, you might want to reconsider. It tends to crumble when you work with it, and cutting and sanding leave you with a snowstorm of pellets and very rough, uneven edges edges. What I'd recommend is a sheet of extruded foam insulation. It comes in 4 x 8 sheets and has a fine texture---takes well to the knife and the sander.

Either way, you want to steer clear of any paint that is oil-based, as this will dissolve either foam product. Latex works fine, but ask for a non-oil-based latex, as there are a few oil-based ones. I've never tried to paint the white crumbly foam, but assume it's characteristics would be similar to the (pink, blue, or purple) extruded foam. That means one coat will do just fine, without a primer, once you peel off the plastic sheet.

Best wishes on your project!


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## Reckers

Also, if you go back for the extruded foam, look for a slightly damaged sheet you can make work. Small dents and such can readily be filled in with spackling compound and sanded. Find a promising sheet, then find a clerk and tell him you found a cull and ask for a price on it. If he doesn't cut the price at least in half, start to walk away. Damaged sheets are really hard for them to sell, so I've found they're pretty aggressive in chasing you down to give a second, lower price to get rid of it.


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## buccsfan64

i read the other threads on the white foam and agree, it does get messy. Most of my cuts I use a wire cutter so it's not too bad. Unfortunately I already glued down the white foam board. I'll go get the other foam for building the rest of the scenery. 

As for the paint, i assume the latex primers should stick? 

Thanks.


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## tjcruiser

I think you'll be fine with latex. I used latex paint directly on pink-stuff foam (without a primer base) and had no problems. Dried nice ... no cracking, flaking, etc.


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## jzrouterman

Latex is essentially a name given to acrylic, water base paint which works very well on any type of foam, even the white. Back in the old days in the sign business, we cut letters out of white styrofoam. We used a foam cutter which was basically an "E" string wired to a 12 volt transformer. The string would heat up and cut through the foam leaving an extremely smooth letter. 

We'd first coat each letter with flat latex, then depending on what the custumer ordered, the letters were either dipped in a vat of Elmer's Glue or painted again. If dipped in glue, while the glue was wet, we'd dip them in a vat of glitter. The color would be at the customer's discretion. These letters when finished looked liked a million dollars. They were used in places such as theatre marquees and auditoriums, etc. 

If instead, the letters were to have a finished coat of paint, we'd coat them with One Shot oil based bulletin paint. Since the foam was covered with latex, the oil base paint didn't hurt it. 

A third thing we'd do to the foam letters in the event the customer wanted the letters to light up and reflect light at night, is we'd dip them in a vat of glass beads while the letters were wet with glue. When a car's light would hit them, they'd shine super bright, very simular to how the reflective vinyl "SCOTCHLITE" of today does.



Routerman


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## tjcruiser

jzrouterman said:


> Latex is essentially a name given to acrylic, water base paint ...


I used to think that latex and acrylic paints were basically the same thing ... generic names for water-based paint. However, a couple of recent threads here on the forum taught me that acrylic-based and latex-based paints are not really the same. Both water based, but acrylic paints tend to be higher priced and more durable than true latex paints.

I Googled a bit some weeks back, and there's quite a bit of detailed comparitive info/descriptions on the 'net. Most of it over my head, but now I at least am mindful of some difference between the two.

Cheers,

TJ


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## Reckers

I don't claim to know anything about paint, but I have seen cans labelled "oil-based latex". I have no idea what the composition is, but mention it to forwarn people.

JZRouterman, that was very interesting and informative. I hope to make use of that knowledge, someday!


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## Xnats

All good advise above.
I'm just going to toss this in because of the scale size. Don't be afraid to dilute your latex up to a 50/50 mix with water. If you put it on full strength and lets say it dries to a thickness of 1/16 of an inch. When scaled to real life that is 10". Just something to keep in the back of your mind as you start on the finer details. If you notice your white foam is not giving you the strength or structural support just cover it over with plaster cloth. Plaster fixes almost anything :laugh: This coating is really just to hide the foam color and serve as a base/ contrast color for when scenery detail is added. 
Please keep us posted on progress, we love pictures of all types


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## tankist

excellent advice on damaged sheets. that''s how i got mine 

Latex paint sticks to the foam very well.


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## jzrouterman

tjcruiser said:


> I used to think that latex and acrylic paints were basically the same thing ... generic names for water-based paint. However, a couple of recent threads here on the forum taught me that acrylic-based and latex-based paints are not really the same. Both water based, but acrylic paints tend to be higher priced and more durable than true latex paints.
> 
> I Googled a bit some weeks back, and there's quite a bit of detailed comparitive info/descriptions on the 'net. Most of it over my head, but now I at least am mindful of some difference between the two.
> 
> Cheers,
> 
> TJ


They are in the fact that both have the same beginning. Case in point: Notice the address of this URL. Notice it says LATEX. Now click on it and notice what the headline description at this site reads. ACRYLIC. http://en.wikipedia.org/wiki/Latex_paint The acrylic paint that's for paintings and models is several times more pigmet and acrylic concentrated than latex. A lot of times I dub Latex as water paint simply because it's water based. When in fact true WATER PAINT is nothing like latex or acrylic at all. It's what is refered to as Tempera. 

Basically, if you go to a paint store and the lable reads latex or acrylic latex, it's water based paint. If you're not sure than read the clean up instructions on the back label. If it's water based, it will say to clean up with water. If it's oil based paint, it will say to clean up with mineral spirits. Oil based latex should not be confused with latex. If it's oil based latex, then the lable will read OIL BASED LATEX. However, if it's water based, it will read either ACRYLIC LATEX, LATEX, ACRYLIC or TEMPERA. 

Water based acrylic should not be confused with some industrial paints called acrylic or acrylic laquer. These paints are usually laquer or zxlene (zxylol) based paints and dry very quickly as do the clear coats and varnishes of this base and are mostly used in sprayers.

Routerman


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