Plaster Mountains and Rocks

Does anyone use plaster to make these things? I have a pretty flat N scale layout and I am in the middle of a stream model. What a mess. You have to really be careful or you get the white stuff all over the rest of the layout.

I must say that stained plaster and/or rocks look very nice. Very realistic. My rock part was about 3 cm high and 50 cm long. Seems more trouble than it was worth, but it does look nice. I still have over a week to finish.

 

I used fiberglass screening and plaster cast rocks over most areas of my layout. I used the same method on my "mountain". I filled in with wood putty and it holds up extremely well.

I used foamboard in only two or three places and I like the plaster effect much better.

 

Flash,

EVERYTHING (mountains/rocks/etc) on my layout is plaster laid over newspaper for shape - very happy with the results... true, you gotta be very careful with covering up everything. For the next layout, everything will be built up with only the foam (or cork) bedding down - no tracks or ballast at all - so I dont have the mess I got myself into this time.

Also the WS foam putty does make carving out rock patterns very easy and very fun - used that in my blast-thru walls.

 

I use "casting plaster" over foam insulation.
And I use rubber molds I made for the rock faces. Then I use the cheapest acrilic paint Hobby Lobby has to color with.

Mike

 

Is casting plaster the same as molding plaster? I am only able to get molding plaster in 100 lb bags (about 40 kilos).

Can't get hydrocal at the LHS; no demand for it. It is too hard for me, anyway.

I used plaster of paris which is too soft, but I am not putting it on a module or anything mobile. Also, I am sealing the plaster of paris after coloring it.

 

Flash:

I used hydrocal for all my rock castings on the JJJ&E, which by the way is all mountainous.

Hydrocal is much harder than plaster and is easier to work with. I also found that hydrocal absorbs earth tone stains very evenly.

The whole trick to working with either hydrocal or plaster is to mix it properly.

From your above response, it seems as if you you had a very soupy mix which always creates a mess and in fact leaves the plaster/hydrocal mix very brittle.

I worked with hydrocal/ plaster for 30+ years in Prostehtic Dentistry, so I'm quite familiar with the properties and how to handle either product.

To mix hydrocal/plaster properly, you must add the powder to a pre-measured amount of H20 and keep adding powder until you have a very stiff mix. By stiff, I mean, if you turned the mixing container over above your head, the mix won't run out.

BTW, the above testing method was the way we learned how to mix plaster/hydrocal in Dental School.

Then vibrate the mixing container on a flat surface to bring any air bubbles to the surface.

Now you're ready to pour the mix either in rock molds or directly on the area you're working on.

If you add water to powder in a bowl, you'll never get a good mix of plaster/hydrocal. It will always be too runny and create a mess in handling it.

If you want a longer working time, simply add a few drops of H20 to the final mix before you vibrate it to remove air bubbles.

Have fun.....

Stay cool and run steam......

 

I used to do all the mountains and hills with Hydrocal over cardboard strips or sceen. Since I have been useing the foamboard on my last two layouts I don't think I would ever go back to that mess!

 

powersteamguy has the good answer about mixing Hydrocal. Do it the way he says and Hydrocal will work great. The stuff is very strong, and takes coloring very well also.
I went to Wally-World( WAL-MART) and bought a plastic kids play/kick ball about 12 inches in diameter. I cut a hole in the top and use this ball to mix my Hydrocal in. Mix the stuff in the ball, use what you need, then flex the ball when you are finished, and the hardened Hydrocal will just fall out of the ball. DON'T DISPOSE HYDROCAL IN THE SINK. You can use your sander for a quick vibrating machine. Just remove the sandpaper from the pad and use a low speed to vibrate the Hydrocal.

 

I use styrofoam for my basic scenery shapes. I shape it by using a pet grooming brush. I do this in the garage and keep my shop vac within arms reach!

I cover the styrofoam with a product called "Sculpt-a-Mold". I think it is a mixture of ground up paper and plaster. It dries fairly quickly. When the plaster product dries, it is very light. I also apply the plaster product out in the garage. I have used it with rock molds. I am satisfied with the results.

When I set everything in place on the layout, I blend the scenery together with plaster cloth. (gauze that has been pre-coated in plaster)

 

I guess it depends on what type of mountains and rocks you are modeling. I think if I had large granite type mountains I would go back to the plaster and molded rocks, but the area I am modeling is all lower type hills and sandstone rock cuts so the foamboard works just fine with the wire brush technique, it even has the right texture when painted,also the ceiling tile method works great too!
Sorry Ken ,no more mudpies!!!!

 

Try Durham's "rock hard" water putty over newspaper. Stronger than hydrocal, carvable (sets in about 20 min), paintable. My favorate by far.

 

When I used plaster, I kept the dried up remains, broke them into manageable pieces, then used that for "rocks", since they looked better than what I could "carve" by hand. I also stained my plaster with various colors of RIT laundry dye. The broken pieces also make good rip-rap and fall realistically down a slope.