Is joint compound safe to use as a diorama base? Are there any special precautions, air quality-wise to use with it? Is Spackel safer to use? I will use one of them to make a thin coating over styrofoam and add small snowdrift then cover with Woodland Scenics snow? No sanding would be involved.
Joint compound should be safe provided it is not the stuff made in China. Spackle will also work and is usually available in smaller containers than joint compound.
That is only if you are sanding it and raising a huge dust cloud in an enclosed room, such as sanding sheetrock joints. Joint compound is basically gypsum and water, both natural materials. The Chinese stuff has many unknown chemicals in it so stay away from that stuff.
Don’t breath the dust if you can help it…I have inhaled my weight I’m sure…it does seem to keep drying and crack sometimes if super thick…it is my main source for alot of things including bases…
the gypsum that makes up the joint compound is okay in small amounts. In larger amounts it can affect the pH locally, which is not great. The more serious issue the silica that can be in some products. If inhaled it can lead to problems in your lungs…which is 100% avoidable by wearing a dust mask. Also if you use spackle in large quantities, read the label. Some spackles contain organic solvents and good ventilation is a must.