I'm starting my scenery and am using Woodland Scenics plaster cloth to form the basic shapes. I have a cardboard strip mesh underneath to support the cloth. I want to try using some heavy paper towels and plaster to "supplement" the commercial stuff. Mainly because of budget. The question arises as to the mix. Should I make the plaster thinner than would be used in a mold, as in rock mold, or stay with the directions on the plaster bag? Also, how long should I leave the paper towels in the mix? A quick dip or soak it? Having used the plaster cloth seems it should be used similar to that, a quick dip.
Plaster should be the consistency of heavy cream. Dip the paper towels in it for a few seconds, long enough for the water to soak in, not so long that the towels starts to tear. (That's why you need the extra water in the plaster, the paper towels soak up quite a bit.)
You'll find that tearing the paper into 2"-4" strips is sometimes helpful. Crisscross them to make the first layer, then add a second, which can be done as soon as the first has set up, even before it has dried. If you wait for the first layer to dry, wet it before applying the second one. (Same principle applies when adding plaster rock castings, etc.) Use the cheapest paper towels you can get, no need to get that fancy stuff advertised on TV. Some people advocate Hydrocal on account of its strength, but IMO it's not needed if you use two or three layers of paper towel over box-board strips. Unless you wanna dance the fandango on your layout, in which case you maybe better use concrete. :-)
Mix enough plaster to last about 10 minutes, else it will start to set up in the mixing bowl. Experience will be your guide for this.
I'm no expert, but, back when I was involved with a club layout, with some quite experienced guys, we discovered:
Ordinary plaster of Paris doesn't work all that well. Hydrocal (sp?) which is what Woodland Scenics uses, works much better. It is available at SOME home centers, usually in a 100 lb. bag. As long as you keep the supply dry, it keeps well, and is still far, far cheaper than the premade strips. This is the stuff they use (or used to) for casts like when you break your leg.
Mix should be about like melted ice cream.
Cut up old cloth works much better than paper towels. Old bedsheets, pajamas, and such. Worn flannel is about optimal, but cotton boxer shorts or poly-cotton dress shirts and such work too.
A fairly quick dip is all that is needed. Just enough to get the plaster soaked in. Then a kind of quick squeeze to get the excess out.
Mix small batches and work fast. Use a disposable container.
If you use coffee (liquid leftover coffee, room temp) for the liquid, it will give you a halfway decent earth base color.
Heavy cream or latex paint. Paper towles of any kind - the cheaper, the more scenery you can do for a dollar. Plaster of Paris does work but Hydrocal is a bit stronger and is the reason why it is called Hydrocal scenery. Use several layers at a time and don't forget the large paintbrush to both put fresh material on and to smooth out the towels. Rocks are fairly easy as you can just carve them from a thick layer of Hydrocal as the stuff takes about 10 minutes to go from soft to hard and that makes it easy to start with the crude shape when soft to the fine details when the Hydrocal is almost setup fully. Work quickly and you can do about a square foot of area at a time but start smaller and get used to the idea.
-- Why do penguins walk so far to get to their nesting grounds?
As others have suggested the Hydrocal should be the consistency of heavy cream, more or less. The latest project at the club used the thin brown, rather coarse, paper towels that come in the large rolls for wash room dispensers. We poured cream consistency Hydrocal into a plastic paint roller pan. Then we would drag a piece of the paper towel (anywhere from ~10"x10" to 2"x10") through the mixture, one side at a time, trying to squeegee (sp?? :) the soaked towel. This would saturate the towel. Then we would drag each side of the saturated towel through the mixture again trying to loadup the towel. Slap the towel over the frame. We put on three layers of this.
We used tag board strips to construct the basic frame. Weaving the strips together we stapled a few overlapping joints to keep them from moving while we used Elmers white glue to secure the rest of the overlaps. It formed a rather stiff frame for the saturated towels.
We used Tempera (sp???) powdered paint to tint the Hydrocal. Dry mix it thoroughly first. Mix a few test batches and let them dry. We practiced on the first layers. We decided not to make each batch with exactly the same recipe. We used lots of brown. Each batch got a slight tinting with one or more of; read, white, black,yellow.
The BIG advantage of tinting the very "white" Hydrocal is that if it chips (and it will chip eventually) you won't see the very "white" Hydrocal.
It was a lot of fun, hadn't played in the mud for a very long time!!