W's Mountain

[Froggy the Great]

My 3yo boy and I went through four cans of expanding foam yesterday and made some mountains:



The base is 24"x48" masonite pegboard.



The idea is to work with him and take this all the way to finished terrain so he can play with his toys on it and I can play with mine.

Anyone have suggestions on smoothing this out, preferably working with the foam itself?  I'll be adding plaster or other filler later, but I want to keep this as light as possible.

[Froggy the Great]

The plan so far is to carve out flat spaces for playable areas, then inset sections of cork as rock. 

Once that's dry, another can of spray foam will suffice for last fillings. 

Then we're going to coat the lake area with foil, cover the whole thing in a layer of latex house paint and pour glue in the water areas. 

Then W and I are gonna go crazy making stuff to go on it.

Lastly we do detail painting and flock and stuff.

[manfred]

Nice start!

I have worked a little bit with this type of foam.  One thing I ran in to that you may want to watch for: after I made the initial foam "piles", I let them dry for several days.  Then I sliced off a portion to get a flat surface to work with and set it aside until I had time to work on the project.  After a few days, I went back to find that the "flat" areas had continued to expand a bit more, adding a rounded surface where it had been flat!

It seems that the interior of the foam may take a lot longer to fully cure than the outer layers.  Keep in mind I am talking about running into the problem a number of days after the first spray.  Maybe it varies according to humidity levels.  I really do not know, but just thought I would mention the experience.

Good luck.  I look forward to seeing your progress.

[Froggy the Great]

I shall definitely keep that in mind.  It says it gets a full cure in 8 hours, but who knows.