Making Styrofoam stick?

I like hot glue for instant gradification and Elmer's white glue if I'm leaving it overnight.

In my experience white glue takes a long time to dry, I have had good results with 5-mintue epoxy...

      Thanks, Jim

That's what I use!

Hot glue.

Another glue that works well is WeldBond. It can be found in craft shops.

Ditto both Liquid Nails and White/Wood Glue...  It's just a matter of which one I have on hand at the time..

As Al mentioned, white glue works as does wood glue. If you really want some industrial strength adhesive, Liquid Nails makes a glue specifically for styrofoam. You lay it out, set your foam down on it, press, and then lift for about 30 seconds to a minute then re-apply your foam. Been using it for set design projects for years and it works like a charm.

I use white glue (Elmer's type). Depeding on how well you water-proofed your base, it may not hold well. White glue works best on a pourous surface and waterproofed wood is no longer pourous. Glues that work well with non-pourous surfaces may be to strong and could melt your styrofoam. Frankly, I never seal my bases and have not had a problem in the last 20 years. You might want to use rough sandpaper where the styrofoam is going to be, maybe even drill a bunch of small holes to give the glue something to bite. Also, when mixing your Celluclay, use a big dollop of white glue and only as much water to get the stuff to the consistency of very thick oatmeal. If you can squeeze water out of your mixture, you have too much water. Add more Celluclay. I also add some earth colored acrylic paint and railroar ballast to the mix for added texture.