Okay guys, I've got myself into a major scenic effort and I need some help, if possible, with how to do large rockfaces on, say, canyon walls. I think continued useage of a given rock mold is going to get very old very fast. Where to go?, What to do??? How to do it? How to get there please>
This H0 scale canyon was made with about six different rock molds. You can get a lot of variation with this type of rock as it can be rotated to give different appearances. This is Tom Crosthwait's Mogollon and Southwestern model railroad in San Antonio. Also, this H0 scale rock quarry wall is about 20 feet long and it was made with a single mold 18 x 18 inches. These molds were home made. This method was done by using molding plaster and then staining it with various earth washes. There are many other ways to make rocks; this is just one. Click here for Torsja's thread about making rocks. He is carving plaster.
What I am doing is gluing together hunks of foam ( from the scrap bag from the base and roadbed stage ). I do it with random sizes building up to the size of the outcopping that I want. Then cover the faces that will NOT be attachment points with whatever plaster you prefer to work with ( from plaster of paris to Sculptamold). The plaster faces can be carved to create the strata look desired. A first coat of base rock color before the carving might help eye the strata. I don't have pics yet - but I will post some when I have the pictures.
You can try a few things to vary the look: 1. Don't always fill the mold full of plaster to vary size and shape. 2. Add carvings to some or all with an exacto knife 3. Re-orient the molds (although not with a strata type rock, since they tend to be at similar angles) 4. Add ground foam lightly, which will vary the look. 5. Count on the overall effect and drama to please most visitors. 6. Retain the right to dismiss any visitor to the layout who mentions either rivet counts or similarity of rock molds.
On the HO San Diego club layout, they used crumpled heavy duty aluminum foil for molds. You'll need to practice with it, and get the crumples really small for N Scale, but it really looks good! http://www.sdmrrc.org/SD_auxHO/BuzzardCyn.htm http://www.sdmrrc.org/SD_auxHO/TecateRidge.htm
So did they crumple the aluminum foil and pour the plaster straight into the foil and then plaster the resulting product onto the shell? What is the process?
I was watching them do the mountains. First, you crumple up some aluminum foil, then spread it out flat again. The size of the crumples will determine the size of the rocks, so we'd be pretty small. They then poured in some hydrocal onto the foil and waited for a "bit". A "bit" is when the hydrocal is starting to set, but does not crack when you bend the mold. They wet the existing hydrocal, then slapped the mold onto the mountain. This takes practice, but it's very similar to making pancakes. :teeth: After a few minutes, they peel off the foil, and voila!
I tried the method Tony described but got a little too anxious and fitted the hydrocal to my 'mountain' too soon. Some of the still-liquid plaster leaked out of the bottom, so be sure to protect any tunnel portals/tracks below your work area. But it does work pretty well otherwise. BTW, I used cardboard cut and 'hinged' to conform to my 'mountain's contours and attached the foil to the cardboard with double -sided tape.
With regard to this aluminum foil method, has anyone tried it with sculptamold? If you mix it thick enough, it shouldn't come running out the bottom because it hadn't hardened enough yet, but how good would the results be?
I would imagine you would lose a lot of the detail, which might not be a bad thing. Give it a try, it might surprise you.
If you properly mix the hydrocal/plaster in a crumbled aluminum pan tray, your results should be accurate with no broken pieces. It's important to let the hydrocal/plaster properly set up. I've had no problem use the crumbled aluminum tray technique on some of the rock work of the JJJ&E. Your results will depend on the mix of hydrocal/plaster &H2O and the proper setting time. If you pull the plaster from the tray before it's set up, your results will not meet your expectations. Stay cool and run steam...........
Not the greatest picture, but I did this whole canyon with a sinlge, large rubber rock mold... The rock mold I have is about 8" X maybe 2'. I was able to use it repeatedly without noticing a repeating pattern by not using all of it each time and by doing some chipping and carving here and there after the Leightweight Hydrocal set up (you need to do some chipping anyway where molds join togeter). My rock mold only has one outcropping on one end that would stand out a lot if it was repeated over and over. The rest is so random looking that it is hard to pick up a repeating pattern. Unfortunately, I cannot recall the manufacturer of this particular rock mold right now. I've had it for years. Russ
Rick, This sounds like a good idea! It would take longer to set up,But it would be lighter than plaster and easier to work when it's dry.
You might check out Bragdons Geodesic scenery, and they have very good techniques for coloring molds, one does not have to be an artist and you can judge for yourself. The bad thing is that visitors have to touch it as it gooks good. Bragdons molds are very good sizeed and the basic thing is purchasing large molds that have the same type stratas, sandstone, sort of rocky or as mine jagged, each mold should be able to use in four or more angles and tie togather. If it cand only be placed in two positions, dont buy it as it repeats to quick I only have four molds and by using geodesic scenery I can see what it looks like out of the mold, with plaster you set it on the mountain and hope it looks good.
Along the line of "practice", I've had some experience with this method now. So far the one word I could put on the results is "inconsistent". Seems in order to get rocks with deep cuts with this aluminum foil method, is to let the casting dry in the mold and then plaster it onto the hard shell. Pressing it onto the hard shell while still soupy (not cracking when bending), can flatten it out too much and loose much detail. So I cast some smaller pieces and let the casting dry in the mold. Some were still too flat. Others that were really going to be rough deep cut rocks came up unuseable because I couldn't get the foil off of the casting. Unless someone has the solution to this, looks like its going to take even more practice. BTW I used "wet water" as a mold release. Recommend something else? There is also the tendency for multiple star-like shapes in the tin foil process. When placing a wet mold on the hardshell I've found it relatively easy to just rub them out. With a dried casting, that option is gone.
Try not crumpling the aluminum foil so hard. Sounds like you are scrunching it. The trick to getting the mold on the scenery without making a mess is a piece of cardboard. Lay the mold flat on the cardboard (1'x6" works for me) and gently move one edge to the bottom of the area you want the rocks. With a deft hand, ploop the mold onto the scenery base. You gotta let it dry there, but not too much or it'll stick to the mold (This happens with rubber molds too!). I count to 60 before removing the mold, but this will depend on the mix and the room temperature. If you get cavities in the mold, use less sugar. Sorry, bad joke. No, what you need is to make the "mold" flatter. We use a wet sponge to smooth out molds. The water will melt the upper layer of still not-quite set hydrocal and allow you to fiddle with removing some imperfections. Keep trying, and write down when it works! you never want to go through this again if you can avoid it! :teeth: Here's what I was able to do using this method, before the rest of the scenery went in. I use desert wind blown dirt to fill in between rocks.
Sculptamold with foil I really did not intend to throw this thread back to the top again, but I did want to make the following information available to anyone interested in the tin foil rock mold method. I've tried the sculptamold with the foil now. In several locations where I needed to "join" castings already in place, I wet down the area with "wet water", then globbed on some sculptamold (premixed thick & colored) in the area. I had some foil already crinkled up good and unfolded. I put it directly on the wet sculptamold and worked it around to make sure the foil was in tight contact with the plaster. I left it on overnight and took the foil off the next morning. Worked quite well, and the foil is not all globbed up with plaster like it is with hydrocal, so it can be used again & again. I've also tried just throwing a bunch of thick sculptamold into some crinkled aluminum and just placing it into a location that had already been wet down with "wet water". Again, left it on overnight and had similar good results.
Thanks for the additional info Rick. I have a few bags of Sculptamold and will give it a shot. I'm at the stage of creating rock faces on my layout.
