Attaching 'Rocks' to scenery base

Model Railroader Layouts and layout building
1

I’ve just made my first rocks using WS molds and lightweight hydrocal. I was wondering if you could give me some tips on how to attach them properly to the scenery base, which is plaster cloth. The rocks were made a few days ago so they’re dry. Do you attach them with more hydrocal and do you simply put enough on to fill any gaps like in the pictures below?

Any suggestions and tips from your experience appreciated.

JaRRell

2

Nice rocks.

  1. Spray area on mountains with wet water (water with dish detergent)

  2. Mix some thick hydrocal and put a blob on the place to attach the rock. (sometimes you need to cut the plaster cloth some to get a proper fit at the bottom

  3. Spray the rock with wet water.

  4. Cram it in place and fill the gaps.

  5. Carve the fill as it drys to look like rock and not cake frosting. ( ome of the guys recomend punching the wet hydrocal with crumpeled tin foil.

The rocks can also be attached with hot glue or premixed drywall seam cement and about a dozen other things. What does not work so well is caulk, because the rocks tend to want to fall out before it drys.

3

I hate posting to add so little, but maybe I can just say that what Art has described is exactly what I did on my first layout where I used plaster cloth in places and afixxed rocks to it. Use the same material as you are bonding, but slap it on as a paste and place the pre-sprayed rock against the slathered hydrocal, hold for a few seconds to let the water in the slurry seep into both outer surfaces, and then let go. Carve as you need to.

Pre-wetting, quite liberally, is a very important step in this process. If you try to place the slurry against dry cloth, or against a mass like plaster rocks, it will not have a chance to chemically set because so much of the water will be lost to the drier compounds adjacent to it…not good.

BTW, hydrocal is not great for painting later…at least, in my experience. If you have tempura powders, liquid acrylic paint from Wally World, or even masonary dyes, you should seriously play with adding them to some rocks and slurry to get something approximating a real rock.

4

thanks Art. I think I remember reading in a magazine once that one guy put the rocks in some water and let them sit for an hour before attaching them, then sprayed the wet water on the base. I’ll try it on one to see how it goes.

JaRRell

5

I’m always grateful for any little thing anyone adds! [:D]

I had planed on using earth colored washes , like ocher, burnt umber etc. for coloring the rocks. That’s something else I’ll have to learn to do.

Thanks for the help, Crandell.

JaRRell

6

i also make rocks the exact same way…but i also found that i can take the mold and place it on the layout as the plaster just starts to “set”…and the rock will completely form to whatever your placing it on…i was alittle nervous at first just “slapping” on a mold that isn’t fully cured yet but the end result was awesome…very little time is spent filling in the gaps behind the molds…hope this helps as an idea!!..tim

7

That’s the best way. Spackle/drywall mud can also be used as a gap filling cement. Wet both sides, butter the casting with the mud and slap it in place.

8

Tim, the next batch I make I’m going to try it the way you describe, and see if I can get them to mold to the scenery shape. That’s the only way I’ll learn to do it and which way I like best.

Thanks for the suggestion.

JaRRell

9

I appreciate the advice. I’m going to try it both ways and see which is easiest for me.

Thanks,

JaRRell

10

i found that if you wait until it is set up to the point that if it starts to crack when the mold is slightly bent…that is the best time…it also depends on your batch of hydrocal and how thick you made it and how fast it actually sets…i like the lightweight hydrocal by woodland scenics because the rocks are real light and easy to trim…just an idea…tim