foamcore to plywood and to itself

Hot glue.

I use wire stabbed through to hold it, or gravity.

I have found success using several different adhesives available in caulking style tubes. The one I am using now is a DAP product called ALL-PURPOSE, BEATS the NAIL construction adhesive. Any Home depot/Lowes type outlet will stock this @ around $3 a tube. Obviously you will need a caulking gun too.

Regarding the use of hot glue mentioned above...I'd be wary of that since the heat is going to melt/deform the foam and make a mess unless there is a method of using it in this application I am unaware of. Just my thoughts.

Bob

flanger posted:

Regarding the use of hot glue mentioned above...I'd be wary of that since the heat is going to melt/deform the foam and make a mess unless there is a method of using it in this application I am unaware of. Just my thoughts.

 

Melting can be an issue with exposed foam, but I have never seen a problem with foam core (which is what OP asked about). Even with the former, if you use low-temperature glue and wait for a bit of cooling before assembling, it is usually no problem.  The big advantage of hot glue is that it permits one to work much more quickly than with glues that have to set. IMO it is under-appreciated by many modelers.

I misread the subject foam core as foam board, and so ignore my suggested method. Sorry for the confusion.

Bob

I use hot glue in my work, Pete.  But I've never been able to stop the spider webs from forming when I use it for modelling.

Is there a trick to it?

Cheers

MaxSouthOz posted:

I use hot glue in my work, Pete.  But I've never been able to stop the spider webs from forming when I use it for modelling.

Is there a trick to it?

Sure! Incorporate them into your landscaping. 

Elmer's craft spray adhesive works well on foam core.  Walmart has it.  Just be sure to protect surrounding areas from over spray.  

I also use it to attach ground covers on vertical surfaces.  Spray the surface lightly to make it tacky then put the ground foam on a sheet of paper or cardboard and blow it onto the surface.

BT

Ten 2" layers of foam mountains are growing on the layout right now.  Using the same  28 ounce tubes of Loctite premium polyurethane adhesive used in my wood work.

Early photo

When using foam with facing it is best to peel it off to facilitate glue drying.

The mountains  I am making are light weight and easily removable for access to the "buried" track work.

I would like to be sure you are asking about foamcore (a thin layer of foam sandwiched between cardboard sheets) and not extruded polystyrene, which is an insulation product used in home construction. I use or have used extruded polystyrene--pink or blue color, but normally the pink stuff--on a lot of layouts in various scales, and highly recommend it. It comes in 2" thick 4x8 sheets and is easily cut or carved, leaving no mess, with a hot foam knife (available at hobby shops, craft stores, and from Micro-Mark, among other places). The extruded polystyrene can be glued to a plywood base with Gorilla Glue or several other adhesives available at any home improvement store.

Not sure about much of anything, as the original poster never responded in three years. He did ask about foam core, though, as was noted earlier. 

I use Great Stuff clamped tight ( less expansive version). Once dry you need a saw to take it apart.

OR  "Polyurethane" Hot Glue much better than ordinary hot glue.

I am a fan of liquid nails for projects.  There are many Liquid Nails products so be sure to get the right one.  Excellent product and reasonably priced.

Ended up with no glue. Taped the seams of the foamcore with masking tape and the building weight will hold it down. Only took 3 years from the original question to get to this point today.

A similar thread, I posted a link to this product.   Some construction adhesives are aggressive to foam.