I need to make some rocks and or boulders for my layout. What type of molds should I use, who has the easiest and best. What do I use to make them, plaster or some other material.
Woodman, I used Woodland Scenics rubber molds and Lite weight Hydrocal for mine. DJ.
You can make your own molds off of real rocks using silicone caulk and cheese cloth, there are videos on youtube showing the process. The molds are easy to make and can be used over again, and it sure is cheaper than commercialy made molds.
Ron
I have used both commercial and home made molds. Some of the homemade ones were made with latex rubber (available at your LHS) cheese cloth spread over the 2nd layer with one more layer on top of that. (The above posts says silicone caulk will work too, don’t have experience with that, yet) Nice thing about making your own molds is that you can choose rocks that look like what you want to model. The simplest molds are made from aluminum foil, crumpled to your desire and spread out, then roll up the edge a little. (Can make quite a ledge with this method.) I have re used these when lucky, by don’t plan on it. I have used both Sculptamold and plaster of paris. I prefer the plaster as I think it takes a wash better. Try a couple of each and see what you like. Both the plaster and Sculptamold castings can be allowed to dry in the mold or put on damp, to conform to contours of your hills. Remember to wet the molds before putting the mix in them.
Whenever I am making rocks I always keep a small piece of crumpled tinfoil handy to put any extra plaster into. I can either call it another hunk of rock or break it up for tallus at the base of a rock face. This way the material is the same and if you use the same wash to soak the tallus, it will be the same color as your rocks. You can also break up chunks if you cut some off a casting to make it fit.
Remember, whatever you use for molds, you do not always have to fill them or use the whole thing. Cut them up, rearrange them and make them look like different pieces of rock. The plaster castings can be cut with a snap saw or other fine saw.
Good luck,
Richard