View single post by Paladin
 Posted: Wed Dec 7th, 2011 12:56 am
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Joined: Tue Jan 24th, 2006
Location: Berwick, Australia
Posts: 2403
Here is shot of the UGLY SIDE of the rock castings. This will never be seen when more rocks are placed.

This method starts at the TOP and works down

Start out by selecting the height you require the rocks to be. Now cut some 2 x 1 to the chosen size and fit them in place. ( nothing critical about placement)

Choose the castings you want to use, Place the mold in to a box that has a couple of inches of sand in it,Now nestle the mold into the sand giving the shape required. Make sure you have about 3 inches of the mold at 90 degrees to give a area that can be hooked onto the 2 x 1 uprights.

I have used casting plaster, Again use what you chose, I am sure it will not make any difference.  I would suggest that you use the same substrate for the entire exercise, Some substrates may have different surfaces that may re-act differently with your paints

Now its time to start hanging the castings, make sure they are well supported on the 2 x 1 uprights. Fix them in place using paper towels ( Cheap single ply ) saturated in a plaster slurry. Don't worry to much about the castings not fitting each other, just get them as close as you can. If the fit does not work well now is the time to play around  or even remove it from the scene, once the plaster towels go off it's going to be harder to correct. The gaps can be filled with paper towel again soaked in a plaster slurry, Then go over it with some plaster that is about to go off. push it into place with your fingers then pick at it with  hobby knife or similar

Now the upper layer is done move down to the bottom and work your way up.

By doing the top layer first you can build the lower molds in front thus working your way down and forward.

As you can see in the photo you will only need about 4 inches of depth for each layer.

If you are doing large area of rock such as I, Get a mate to give you a hand.  When plaster starts to go off it all starts at the one time. It can be a little rushed. If you are on your own I would suggest doing small areas at a time until you get comfortable with it

The molds I used are home made with couple of commercial ones. My friend Peter has made about 50 molds and he kindly let me use them. They are latex rubber and appear to stand up well. Don't be in a hurry to remove the casting from the mold, do it carefully and you should not damage the mold. The first time I attempted to remove the casting from the mold I was not game to apply to much force, but it does require some effort, just a little bit at a time.

Hopefully I have explained things well but if not fire questions at me.

Don McL
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