04-11-2009, 03:38 AM
Now the real fun starts - and it's getting messy! Before you really start, make sure that you have spread ENOUGH papers or plastic foil below your workspace to protect the floor, benchwork and/or underground tracks from plaster drippings!
All those paper wads are covered with strips of torn-up paper towels, which were dipped into Plaster of Paris (PoP), into Hydrocal or some other sort of spackling compound.
First, in a shallow bowl you prepare a PoP-'soup' with the consistency of pancake batter. Always dump PoP into water, then start stirring - not vice versa! This way you'll have almost no problems with air bubbles and/or lumps.
Then you pull your paper strips through this mass, covering both sides of the paper. (Another possibility is the use of medical plaster bandages which are normally used to fix broken limbs. They are sold in rolls. You cut off the desired length and dip them shortly into water.)
Then you cover the newspaper wads with these strips, overlapping them about 1/3rd of their width. After you are through, repeat the whole thing and put a second layer over the first. When the plaster finally hardens, you get a stiff shell which is both light and rigid. The more layers you add to the shell, the more rigid it gets.
You don't have to work with great precision (hey, nature doesn't it, too). If there is a part which doesn't satify you, just cover it up with another layer. Or rip it out and replace with a new web of strips. If you put new strips over a shell which is already dry, you should wet it first with 'wetted water' (water with a few drops of dishwashing detergent). ALWAYS add new PoP only TO A WETTED surface! Otherwise the new PoP will not harden properly, because the dry shell underneath sucks out the water from the freshly added paper-PoP-strips.
After the shell has hardened, you can rip out the newspaper wads - you don't need them anymore!
12. - 14. The white base shell shows in many places, how the strips are laid out. You see that the strips also can be laid out in a criss-cross pattern, they can follow the 'flow' of the rock walls - or they follow no order at all! :-)
All those paper wads are covered with strips of torn-up paper towels, which were dipped into Plaster of Paris (PoP), into Hydrocal or some other sort of spackling compound.
First, in a shallow bowl you prepare a PoP-'soup' with the consistency of pancake batter. Always dump PoP into water, then start stirring - not vice versa! This way you'll have almost no problems with air bubbles and/or lumps.
Then you pull your paper strips through this mass, covering both sides of the paper. (Another possibility is the use of medical plaster bandages which are normally used to fix broken limbs. They are sold in rolls. You cut off the desired length and dip them shortly into water.)
Then you cover the newspaper wads with these strips, overlapping them about 1/3rd of their width. After you are through, repeat the whole thing and put a second layer over the first. When the plaster finally hardens, you get a stiff shell which is both light and rigid. The more layers you add to the shell, the more rigid it gets.
You don't have to work with great precision (hey, nature doesn't it, too). If there is a part which doesn't satify you, just cover it up with another layer. Or rip it out and replace with a new web of strips. If you put new strips over a shell which is already dry, you should wet it first with 'wetted water' (water with a few drops of dishwashing detergent). ALWAYS add new PoP only TO A WETTED surface! Otherwise the new PoP will not harden properly, because the dry shell underneath sucks out the water from the freshly added paper-PoP-strips.
After the shell has hardened, you can rip out the newspaper wads - you don't need them anymore!
12. - 14. The white base shell shows in many places, how the strips are laid out. You see that the strips also can be laid out in a criss-cross pattern, they can follow the 'flow' of the rock walls - or they follow no order at all! :-)
Boss of the Trim Creek & Western RR (H0 & H0n3)
Running through the hard-shell mountains, not around them!
Running through the hard-shell mountains, not around them!