Drywall Mud

Does that also mean that patching plaster is a powder where you must add water yourself, and drywall mud is premixed with water and ready to use right away?

Yes,

Most drywall mud is ready mixed.

not sure about the “patching plaster” but the “mud” yes is premixed from ether a pint/quart up to arounh 5 gal buckets but you can get it in 25 lbs bags or so and mix it up yourself

I’ve been using drywall mud on dioramas and layouts for years. I think it works better than plasters because it doesn’t dry in 5 mins. and you can work with it.

Once it’s dry you can paint it or use Woodland Scenics approach and spray dyes or thinned paints on it to color and stain it to simulate rock faces or outcroppings or you can mix paint [acrylics or dyes] into the mud before you apply it.

If you want smooth, flat fields it’s very easy to achieve them with drywall mud and a wooden roller, [just make sure the wife doesn’t find out!! LOL], just apply a thin ,1\4 inch or so ,coat and roll it out. The results are very nice and it dries pretty fast.

At $12 for a 5 gal. bucket you’d be hard pressed to find a better deal, and if you need time to work in your contours and shape your landscape you can’t beat drywall compound, plaster will dry so fast you won’t have any time to work with it.

Folks:

In case anybody wants to know (nobody asked, true), drywall mud is basically clay, a vinyl polymer (I’m pretty sure it’s the same one used to make hot glue sticks and some foam rubbers!) and fillers. It dries, and does not set up into “stone” like plaster. Some patching plasters are similar, made of glue and fillers. Others are just gypsum plaster with retarder added. To complicate things, there are also powdered setting-type joint compounds sold.

I have used premixed paste joint compound for mountains on screen wire. It’s pleasant to work with, but stays soggy a much longer time than plaster. It’s more resilient and rubbery when dry than plaster is.

I’ve often thought that joint compound could be used with paper towels in a revival of the old-fashioned texture-paint method – texture paint was glue and fillers, and the properties seem similar. I haven’t tried it yet.

Sure - it will work. It might crack if you make it too thick but I’ve put it over styrofoam. I use an old paint brush and jab it with the bristle’s to add texture. You can use a damp sponge to smooth it. When its dry just paint it with some latex earth or rock colored paint.

Duncan

If anyone is concerned about the dry time of joint compound, use a faster setting mud. You could use mud with a dry time ranging from 20 min. to several hours depending on which type is used. The only drawback is that it comes in powder form so you would have to mix it. It will also be harder to sand and will require a little more effort to smooth out, but again it hardens much quicker