I’m using blue (Dow) foam on my layout for the first time. Most articles I’ve been able to find about the subject, recommend “foam compatible glue”. Unfortunately (so far) nobody explains what that means or offers any brand names. Any suggestions? Thanks - Bill
If you look at a brand like Liquid Nails there will be one labeled “foam safe” or “projects with foam”, something of that nature. I just recently used glue by DAP that is called "Paneling and Foam. It come in a tube like caulking and is found in paint departments. I bought mine at Home Depot and Lowes but most hardware stores have it. Just make sure it say safe for foam and the brand does not matter
Anyplace that sells home supply stuff will have it. It’s glue homebuilders would use when working with the blue or pink foam insulation sheets.
DO NOT use Superglue! I made that mistake 
On the plus side, I know now what cyanoacrylate does to insulation foam! Cheers!
Cheap latex caulk. Yellow or white Elmer’s glue. These all work well and are foam safe.
–Randy
Thanks… I’ll check Lowes. Here’s a picture of the progress so far. I’m thinking about glueing the foam pieces together and then removing the entire thing for carving in another room to cut down on the foam chips. - Bill
Low Temp Hot Melt Glue. I have tried all the others and they all work, but may take several days to dry. If time is not an issue, fine, but if you want to carve and shape as you go, LOW TEMP hot melt is wonderful.
I hope that doesn’t mean you’re thinking of NOT gluing the foam pieces together. Even though you’ll most likely cover it with sculptamold, plaster or some such, they need to be glued together to keep them from moving while you apply the top coat.
Bill,
I like and use DAP Alex Plus Acrylic Latex Caulk Plus Silicone. Why?
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Cost: $2/tube - It can be found at either Lowe’s or Home Depot.
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Starts setting up in 45 min (I let it dry overnight) - This gives you ample adjustment time for your pieces.
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Yields a VERY strong but flexible bond (unlike Elmer’s glue) - Changes can be made fairly easily by gently prying pieces apart with a wide spatula or putty knife.
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Works well on a variety of surfaces: Foam-to-foam, foam-to-cork, cork-to-track, etc.
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Comes in a variety of colors (10, to be exact) - Most home centers have either the clear or white.
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Very little odor or hazardous chemicals - Some of the other “foam safe” adhesives (e.g. Liquid Nails for Projects) still have some pretty nasty chemicals in them.
I’ve been using the DAP caulk for 2 - 3 years now and have been very happy with the results. Hope that helps…
Tom
That’s what I use but on the west coast it costs about $2.35. So much easier to fix mistakes when you glue the track down with caulk!
I wasn’t able to find Liquid Nails or DAP “foam safe” at my Lowes (Vestal, NY) but they had something called PL300 which was only $3. Worked pretty good. The upside is that it is blue and matches the Dow foam that I’m using. The down side: The drying time is listed as “depends”. (Big help). Although they recommend clamping for 24 hours. That’ll work for me. Now I need to borrow my wife’s hot wire cutter. 
- Bill
Check your local Walmart (if you live in the states). I’ve found 4-packs of latex caulk for less than $4.
Bill, all I’ve ever used is PL300,for the layout and as a contractor, when working with foam.
Terry
Ordinary Latex caulking compound. Comes in tubes for a caulking gun. Sold at any builders supply place, Home Depot, Lowes, hardware stores. Get the stuff that dries clear, it becomes mostly invisible when dry. The stuff sticks foam to foam, foam to wood, foam to cork, plastic tie strip to cork, foam or plywood. and a lot of other things too. Will not eat foam. Takes over night to dry enough to hold the foam in place and probably a couple of days to reach full strength.
I have used the foam tack glue and it works well. I use that to glue down Homasote. The nice part of using Foam Tack is that it stays a bit flexible. Of course it is expensive.
I have looked for alternatives but I have yet to find one that stayed flexible like the foam tack, caulk it close but the downside of that is it is hard to keep around if you do not use the whole tube.
Doug
I use Polyseamseal All-Purpose Clear latex acrylic adhesive caulk, the same stuff I use to fasten my track down.
Adhesive caulk works better than white or yellow glue since when dry, it’s slightly elastic. Especially for those of you with modules, if you use white/yellow glue and your module gets bumped around, one good jolt can knock your foam base loose. With caulk, the seal absorbs the force of the jolt.
I’m surprised no one has mentioned spray adhesive. As with other adhesives, one needs to check that it’s appropriate for foam. I prefer a spray adhesive such as 3M Super 77 for several reasons:
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If it’s applied to both mating surfaces and allowed to dry to a tack it will act as a contact adhesive and the surfaces will be permanently joined on contact. This is handy for quickly building up layers of foam. The ONLY wait is for the surfaces to tack – NO overnight (or longer) waits.
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If over spray of one surface needs to be avoided then spray only one side, press the surfaces together and then take them apart. Allow it to tack as before and rejoin for a permanent mating.
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If it’s applied to only one surface and immediately joined then the parts can be repositioned for a short time. This is handy if for some reason the alignment is critical.
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Once the joint has set it does not impede further operations. By this I mean it can be easily cut with a hot or cold knife/wire and the glue joint does not make it hard to shape. I’ve found the glue joint formed by Liquid Nails or caulking to be very difficult to rasp and the smell of cutting it with a hot knife/wire is… well, unforgettable.
There are adhesives designed for Foam. The come in standard caulk gun tubes and are easy to use. Most will clean up with water. Liquid Nails for Foam Projects and PL3000 are two brands I have used with good success. If gluing foam to wood or masonry I use one of these, or equivalent. Get a good caulk gun, and get a cap to seal the tube after it is opened.
For foam on foam, or for track on foam, I use latex caulk. If you cap the end of tube, they sell caps at Home Depot, or tape it to keep out air, a partial tube will keep for a long time. I have kept some tubes for several years. Be sure to spread the caulk in a thin layer, I use a piece of plastic milk jug for a spreader. The thinner the layer the faster it dries and less likely it will eat the foam.
Doug Harding
if it meets your needs…trying using a hot knife for cutitng and shaping your foam…sawing it can be a big mess. Use a heady duty foam knife and not those wire ones…they can’t handle the dense foam…
Larry
For years, I used the “Liquid Nails for projects” blue-labled, for FOAM, when it came in a tube for use in a caulking gun… was useful for all sorts of modeling, paper to wood, wood/wood, etc.,dried in a couple hours, no smell, and cost about $2 a tube… then they changed the packaging to a tooth-paste sized tube, and raised the price to about $4 bucks… I don’t use it any more!
Trainman