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Hi everyone!
My theatre is currently working on a production with a cave as a setting. The scenic designer is wanting to use spray foam (or just foam in general) for the texture on the walls and stalagmites. I have no experience with foam and have no idea which direction to go with brand/type of foam. Any suggestions are highly appreciated!
As of right now I have a general shape of stalagmites that I have sculpted from chicken wire, I was thinking it would make a good base for the foam?
Depending on size of cave…for small things we’ve used aerosol cans of Great Stuff. Spray on and carve for shaping after it dries. We have used the spray foam Froth Pack extensively for larger caves. A product from Dow Corning. They’re not cheap but you can get about 600 ft.² of coverage. Also right now you might find delays in getting one since supply chains are slow. Technique tip: start with thin coat and build up subsequent coats as needed using bumble bee type circular hand movement. Don’t hesitate too long in one area or it will build up quickly. Carve and shape after it’s set. Helpful tools: horse curry comb. Make sure to cover and mask well anything you don’t want it to touch. It’s very sticky.
Spray Foam is such an alluring product. It can solve so many challenges. But I avoid using it because it has ISOCYANIC acid in it , (Or something like that) that I believe there is no respirator cartridge that can filter.
PLEASE do your homework and look at the SafetyData forms for everything you are thinking of using.
I have been going super old school with projects like this. On chicken wire I would pad the suface with crumpled up brown paper, then use muslin dipped in scenic dope to create the cave walls.
Good luck. BE SAFE
Abby Hogan
PCPA
Asking for clarification: when you write ” spray foam (or just foam in general) for the texture on the walls and stalagmites,” are you talking about creating the shapes or the texture? If it’s shapes/finishing the shapes, .I totally second Abby’s advice to know what your situation can handle: if the spray foam off-gases any “-cyanate”, which many products like that do, you need an air-supplied set up (SCUBA) for everyone who shares airspace with it. If the material does, and you don’t have the training and equipment to use it without, don’t use it. That’s administratively managing your situation, which OSHA recommends as the first line of health and safety.
Since you already have a wire armature for it, Abby’s suggestion is great for an additive process: paper is one of the cheapest, most efficient and most versatile materials you can stock in your shop, as are any of the generic “white” glues that will make it stay put and adhere. I’m about to create a whole bunch of tree bark with paper and glue next week.
If you’re talking about texture, like, rough or smooth, you can mix great textures from glue, paint, joint compound, vermiculite, perlite, EPS foam crumbs, (and the list goes on) yourself to apply the shapes you create, and then either apply them with a brush and tool them to get the effect you’re looking for, or get a hopper gun (see any of a million youtube videos) to spray it on (and then tool as desired).
Lots of scenics have their own special recipes for that kind of thing if it’s what you’re after.
Looking forward to hearing what you end up doing!
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