Foam to Plywood

Model Railroader General Discussion (Model Railroader)
1

I have 1/2 inch blue foam for my layout. I’m gonna cover the entire plywood surface with it. Heres my question. How do i attach it to the plywood?

2

I just tried gorrilla glue on a bunch of 2" pink insulation that is the basis for my hills. It set up fine and is really really attached. What i liked about it was that is was easy to apply. I used weights (about 40lbs) on top of it to weight it down to dry. Now i have the next level to do. Bill

3

Foam friendly latex adhesive!!! Make sure it says it’s for FOAM!!!
Liquid Nails is one brand name.
Make sure it says it’s for FOAM!!!
You usually find it at either Walmart or Home Depot.
Make sure it says it’s for FOAM!!!
I’ve done this to great results.
Make sure it says it’s for FOAM!!! [;)]
One thing I did with the first ply of foam was to use drywall screws to hold the foam to the plywood making sure I used a variable speed drill & stopping the head of the screw just as it sat flush with the top of the foam.

Gordon

4

When I did mine I used “Liquid Nails For Projects”. Weight it down real good overnight (a good way to make use of all those back issues of MR you have laying around).

Ed

5

Thanks

6

There are lots of systems that work, including regular yellow carpenters glue. Anything you choose, you need to weight or clamp it, and be patient - letting it set up for several days.

7

Definitely let the adhesive sit for a few days. The biggest “problem” with gluing to foam is that it doesn’t allow for air circulation, so it takes glues forever to dry. As for which adhesives to use, basically any will work, so long as they’re foam safe. I use wood glue, but any other “project” glue will work as well. Liquid Nails will work on a wood to foam bond, but they actually don’t recommend it for foam to foam bonds.

8

Thanks for the info guys!

I originally considered using “homasote” for my upcoming layout but have decided to go the “Blue Foam” route, instead. My wife’s cousin has it on his HO layout and finds it easy to work with. I’ve heard good things about it from other modelers.

One observation though regarding my cousin-in-law. Instead of plywood, he used a pressed “wood/carboard” type material as a base. He got it from the hospital where he works at. It’s not homasote, and it’s about "1/2 thick. Problem he has is that the foam and base has sunken in a few spots, so at times when his trains roll over those sports the will uncouple. He’s using pop sickle sticks to shim up the spots.

I guess it goes to show that it’s worth spending a few extra dollars to do it properly the 1st time!

9

If your layout is going to be in a basement or any place else ( garage, etc. ) that is prone to humidity, or dampness, and you are using plywood ( I am ), it is a good idea to apply water seal to the plywood. Plwood loves to absorb moisture. Some people think that the bonding glues for the plys is sufficient not cause absortion…this is NOT true. I have tested this, and the board will warp and bend with enough moisture/humidity, even 3/4"