Painting Builder's Foam

[Jeffrey]

For those of you who have worked with pink insulation foam, how do you paint/glue it? I'd like to spray paint it but I'm afraid it'll dissolve. I've used tacky glue to glue the foam pieces together which worked fine. Would carpenters glue be good to glue the foam to plywood or maybe some kind of adhesive caulk/liquid nails?

[KathieB]

Why not try spraying a scrap piece and see what happens. If I recall correctly, I pinned the roof pieces of the White Orchid to a slab of contractor's foam to spray them with red Krylon. I don't believe the foam was affected.

I should think the wood glue or liquid nails would work to adhere it to plywood, but again, test a sample. The glue might also dissolve the foam.

[havanaholly]

Check out the Team Haunted House blog, Minis on the Edge used bufoam for the hill she carved her house's basement into. If she didn't describe it in her part of the blog, perhaps you could PM her and ask.

[Selkie]

I just used wood glue to attach some to a board and it's holding up well.

There is a special adhesive just for the foam that contractors use that comes in a tube.

I suspect that is important for them because of needing it to hold up in wet and humid conditions.

As to the painting, you need a water based paint - not a solvent based to be sure you don't have an "accident."

Sometimes the solvent ones can be used after you have based coated it with an acrylic type first.

Once it is sealed the solvents seem to work ok. There are water based spray paints but they are hard to find.

As an aside, interesting divots and holes appear from the solvents that can sometimes be wonderful landscape components.

It's just that you can't be sure what you'll get.

[Jeffrey]

i did very lightly spray a 2" square of the foam with matte green spray paint after posting this topic. I just checked it and it melted only a very little bit but i'm planning to use that stone textured spray paint and you have to lay that on a bit thicker.

hmm maybe a coat or two of latex primer first...

[havanaholly]

i did very lightly spray a 2" square of the foam with matte green spray paint after posting this topic. I just checked it and it melted only a very little bit but i'm planning to use that stone textured spray paint and you have to lay that on a bit thicker.

hmm maybe a coat or two of latex primer first...

Try it on another sample to see how it works.

[KathieB]

hmm maybe a coat or two of latex primer first...

Or gesso?

[sparklepuppies]

For my son's amusement park project, we glued the foam on to the wood base with both tacky and wood glue. Each person had a bottle. It held fine. We used acrylic paints, and those worked well. So if your spray melts it a little, I bet a little primer would work well, like you were thinking.

[Roxxie2]

I just used Acrylic craft paint on the foam and Tacky glue....no issues.

[Jeffrey]

Or gesso?

you know, i hear about gesso all the time (mod podge too) I've never ever used either of them or looked into what they are exactly.

[otterine]

Gesso is somewhat like an acrylic paint - found in the artists' aisle. I used grey gesso to seal builder's foam before painting, but I didn't use spray paints...just regular acrylics. I think it comes in white, black and grey. I used Weldbond to attach the foam to the plywood (before sealing and painting) and to attach pieces of foam together because that was recommended on a scale model diorama site. It worked well.

[KathieB]

Gesso (according to Wikipedia)

Gesso (Italian:ˈdʒɛsːo "chalk," from the Latin gypsum, from the Greek γύψος) is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these[1]. It is used in artwork as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it

The original "real" gesso uses rabbit skin or fish glue as a binder; modern versions use casein or white glue as a binder. It is usually applied in several thin layers, and when dry can be sanded velvety smooth.

When buying gesso recently, I've seen only acrylic gesso at Hobby Lobby and Michael's. Krylon has a gesso spray (a surprise to me) at Blick Artists's Supplies) as well as both traditional and acrylic gesso.

[Jeffrey]

Ok I guess I'll try the gesso. Is it thin/watery or thick like acrylic?

[KathieB]

Ok I guess I'll try the gesso. Is it thin/watery or thick like acrylic?

It is a creamy consistency but can be thinned with water. It will get thicker over time. A dash of water will thin it back down again ... or you may want a thicker application to resemble rough plaster or something. It's a versatile medium.

[kat57]

I'm so glad Jeff needed this info!: This topic has been a very informative lesson for me,as I have never used gesso and have read about it so many times in so many mini building projects. 'Looking it up' didn't really help,as I've never seen it (used) first hand.Thank you,Kathie,for making it easy to understand it's formulation,texture,and uses! Now I can decide if I want to purchase some to experiment with.

Thanx to Brae for detailing how to use it with builder's foam.

Now,if someone could show and tell me exactly what 'builder's foam' is and what it's actually used for (Building something,obviously!),I'd be even better off!!

[Jeffrey]

Builders foam is what it's most commonly called around here, but it's a real life insulation product found at Home Depot manufactured by Owens Corning and it's bright pink. (it even has the Pink Panther on it!)

It comes in various sizes and thicknesses. 1" x 4' x 8' is most common but I found 1" x 2' x 2' squares which is what i used and is definitely a lot more manageable... Lowes carries its own blue variety as well.

http://www.homedepot.com/p/Owens-Corning-FOAMULAR-150-2-in-x-48-in-x-8-ft-Scored-Squared-Edge-Foam-45W/100320352#.UlMbXSRQGn8

http://www.lowes.com/pd_304089-210-304089.0_4294858106__?productId=3122445&Ns=p_product_qty_sales_dollar|1&pl=1&currentURL=%3FNs%3Dp_product_qty_sales_dollar%7C1&facetInfo=

[otterine]

I've purchased the pink foam in less than 1" thickness - I think it was 1/2". I know they also sell a blue kind at Lowes but it has different shaping properties from what I've read. It's better than the white styrofoam which gets everywhere! When I bought the 4' x 8' pink foam sheet, the guys at Home Depot cut it into four pieces for me so it would fit in my car.

Also, the pink foam as a film on it that you peel away before you use it in your mini projects. :yes:

[havanaholly]

Isn't the main difference between the pink and the blue density? Micro-Mark sells a "hot knife" for cutting builder's foam that's basically a hot wire, so you melt your cuts and elimminate the "fluff".

[Jeffrey]

Brae, mine didnt have any peelable film on it.

[Jeffrey]

Isn't the main difference between the pink and the blue density? Micro-Mark sells a "hot knife" for cutting builder's foam that's basically a hot wire, so you melt your cuts and elimminate the "fluff".

I don't know of any difference between the two because i've never even looked at the blue one at Lowes but from what I've read online most people prefer the pink for this type of application.

[kat57]

Thanx,Jeff,Brae,and Holly. It sounds like a really cool product-kinda like "Super-styrofoam"?! (And I love working with styrofoam!) At least I know for sure now I've never seen it in a real life application-I never had a (real life) house built or any kind of building renovations done. I'm sure my old home had the old fluffy fiberglass insulation,having been built in the '70s. So,one more question-can it be cut with a craft knife or just the hot knife?

[Jeffrey]

I cut it with a kitchen knife! (CAREFULLY) It's very carvable.

Weirdness alert!

if you have a scrap piece you can blindly, gently, & repeatedly poke it with an x-acto knife which is very therapeutic.

[GirlPiper]

I use a saw or a bread knife--just like styrofoam. It's a rigid insulation used up north here on vertical walls since it doesn't sag over time like fiberglass batts do.

[havanaholly]

I think the hot knife is for carving it into terrain features; a lot of model railroaders use it for landscaping.

[KathieB]

I think the hot knife is for carving it into terrain features; a lot of model railroaders use it for landscaping.

The hot knife is for cutting shapes in the flat boards and/or shaping bulkier pieces where the boards have been glued into blocks. Lloyd uses a hot knife when he's cutting styrofoam for his sculptures.