plaster over foam

[Anonymous]

i'm about to plaster over my polystyrene foam mountains...adding moulds in some cases and carving in others.....should i paint the poly first with an acrylic/water based paint or does plaster happily adhere to the foam.
grateful for some guidance/experience here.

[Anonymous]

i'm about to plaster over my polystyrene foam mountains...adding moulds in some cases and carving in others.....should i paint the poly first with an acrylic/water based paint or does plaster happily adhere to the foam.
grateful for some guidance/experience here.

[Anonymous]

Try plaster cloth on the foam first for strength and adhesion, wrap the cloth around the entire foam mountain. Then anything you add on top of the plaster cloth will stick like STAS.

If your mountains are tunnels over track you might want to make them 'lift-off' for track cleaning access. Disc magnets can be used to hold them in place when not lifted.

[Anonymous]

Try plaster cloth on the foam first for strength and adhesion, wrap the cloth around the entire foam mountain. Then anything you add on top of the plaster cloth will stick like STAS.

If your mountains are tunnels over track you might want to make them 'lift-off' for track cleaning access. Disc magnets can be used to hold them in place when not lifted.

[Anonymous]

I put plaster on unpainted expanded foam mountains 6 months ago. No problems. I also used spackling compound over some hills at same time. No problems. I even put flock grass right on it with glue, but painted these areas first so thin spots didn't show. Here's a tip, you can smooth and sculpture expanded foam with trash bags when unset and they peel them right off when set, but the trash bags add days to the setting time. Plaster, spackling paste, and whiteglue sticks to expanded foam really well, it soakes into the pore and makes a mechanical bond. You will destroy the foam trying to remove said items. Painting would reduce this bond.

[Anonymous]

I put plaster on unpainted expanded foam mountains 6 months ago. No problems. I also used spackling compound over some hills at same time. No problems. I even put flock grass right on it with glue, but painted these areas first so thin spots didn't show. Here's a tip, you can smooth and sculpture expanded foam with trash bags when unset and they peel them right off when set, but the trash bags add days to the setting time. Plaster, spackling paste, and whiteglue sticks to expanded foam really well, it soakes into the pore and makes a mechanical bond. You will destroy the foam trying to remove said items. Painting would reduce this bond.

[Anonymous]

Just an idea to throw out there for you guys. I found some ceiling tiles that were being trown out by a company once. As they were walking them outside to throw them away I stopped them. I went in and asked the manager if it was ok if I took them. He was just as happy to see them either in the trash or elsewhere, so I took them. Needless to say with the help of a kitchen knife and some plaster my mountains came out wonderful

[Anonymous]

Just an idea to throw out there for you guys. I found some ceiling tiles that were being trown out by a company once. As they were walking them outside to throw them away I stopped them. I went in and asked the manager if it was ok if I took them. He was just as happy to see them either in the trash or elsewhere, so I took them. Needless to say with the help of a kitchen knife and some plaster my mountains came out wonderful