A few years ago some one on here posted a recipe of how much water to plaster that they used to make rocks from WS rubber molds. Also, there was a recipe I used to make my own plaster cloth using paper towels or fabric softener sheets, all I can remember is you put some vineger in the mixture, it kept the plaster from setting up too quickly, does anyone know the water to plaster mixture.
I think most plaster comes with the mixing instructions on the package. What I have recommends 2 parts plaster to 1 part water. I think most are similar. I have had very good luck making rock castings using WS molds and home made ones, using WS Latex Rubber, reenforced with a layer of cheeze cloth between a couple of the layers of the rubber.
You can use plaster with paper towels, dryer sheets, rags or cheeze cloth to stand in for plaster cloth. Some folks find the mess of the plaster a bit much. In its place you can use white glue. Buy a gallon thin it slightly and proceed as with the plaster. You can find examples by searching under "glueshell".
Good luck,
Richard
Vinegar is added to slow the setting time
Salt is added to speed up the setting time.
For molds, I use a 1 to 1 mix and add salt.
Other modelers use different ratios. Find one that works for you and write it down.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
I've had great luck with hydrocal and vinegar, otherwise it sets way too quickly
matthew
Hello I like to use sheet rock brand easy sand 5 comes in 18 lb bag for 6.40 . It sets up in 5 min on a wall. About 8-10 min in rock molds. I like to mix it so smooth like cake mix seem to flow better. Hope this helps Frank
If I'm only making one rock casting at a time, I skip adding the vinegar. If I'm making more than one casting, I add the vinegar. When the plaster sets to the point where it cracks when I flex the mold, I press it into place on the scenery base. I made some "pins" out of wire hangers. They're "L" shaped and since my base is foam, I use them to hold the mold in place until the casting has set up completely. When it's set up hard, I carefully peel the mold off. I make some thicker plaster to blend the casting into the surrounding rocks, with vinegar added. I tried patching plaster, and for some reason, it doesn't take stains as well as plaster of paris.
Marlon
See pictures of the Clinton-Golden Valley RR
Hi Rock Makers,
Just an add on here.
Add the plaster to the water in smaller amounts while mixing well. ( not the water to the plaster )
I like to have it like a thinner milk shake.
Once you have it in the mold bang the table it is sitting on several times with your fist, and these two things will help keep out any bubbles that might have formed.
I'm making quite a few of my own right now.
Johnboy out..............................................
from Saskatchewan, in the Great White North..
We have met the enemy, and he is us............ (Pogo)