New rock

You can make your own latex mold of the rock with this Woodland Scenic product:

 

Liquid Latex

 

You brush on multiple coats of latex allowing it to set between coats. Adding some gauze material in between a few of the coats will strengthen the final mold.

 

Jim

 

 

 

 

Thanks, Jim.

 

Never done this before and am a bit concerned about my skills.

 

Dad always said if you don't know what you're doing find someone who does and ask. 

It's really not hard to do. Just use a cheap disposable brush to apply the latex. Leave it in water between uses.

 

If you can do it outdoors on a warm day in sunlight, the latex will set up much faster. Otherwise, it's a project that will take several days. I remember you talking about a move to the Prescott area. If so, your warm Arizona sun will make the process much easier and quicker. (Yes, I'm jealous!!!!!! )

 

You can tell by the color change when each coat of latex is set. Peel the finished mold off the rock surface slowly and carefully to avoid tearing.

 

The castings can be made using hydrocal or plaster of Paris. Wet the mold first with "wet water" (water with a few drops of dish soap), and mix the plaster to a soupy consistency.

 

If you are careful with the mold, it will give you many castings over the course of its life.

 

Jim

Follow Jim's advice. You can pick up the latex from Michael’s. Spray the rock surface with some water with a drop of dish soap and paint the surface. Make sure you get around the edge, so you will have sides on your mold. A half inch should suffice. Let the coat dry and paint on another coat. When I made them I did one coat every day. After you have about five coats on the mold, get some gauze type material. I found mosquito netting at JoAnne Fabric.  Cut a piece to fit the mold and apply it to the mold.  Paint another layer of silicone on the mold and repeat until you have about four layers on top of the gauze.  I have heard about people using a heat gun to speed the drying time, I was never in a hurry.  Carefully peal the new mold off your rock and start making rocks.  You can also turn the rock over and make another mold.  I used a one inch cheap brush and stored it in a ziplock bag between coats.

All suggestions are excellent. As your mold is rather large you will need quite a bit of latex probably two jars. This will put you about $30 in material, maybe you should just buy a mold.

     When you decide to build your mold, make sure the surface is flat and put some border around the rock. You probably will need a dozen or more coats of latex as the rock is 5 inches thick. A thin coat will dry overnight so give your self time. You could use drywall mesh instead of gauze and it is much stronger. When your mold is complete. you can put a base of silicon caulk on it so it lays flat.

     If you fill this mold with plaster or whatever it is going to be heavy. I have used pieces of foam to fill but be careful and not compromise the strength. If it does crack, scultpamold or drywall mix can fill in before painting. Don't forget to show us pictures.

 

     These walls and portals were all made from 3 molds.

 

Ray Marion

To support irregularly shaped molds while filling, I support the mold in a shallow sandbox made by filling a high-sided cookie sheet with sand and nestling the mold into the sand.

 

Jim

Ray,

  Nice work. For your original walls that you are copying, did they have the stone work already or did you need to carve the stones out once the mold is released? 

 

Tom 

Tom

 

    They are copies of ones made of hard foam. I have carved the pink and blue for straight walls. However there is a thin flexible foam you can carve if you need curves. Search for Chugman and his layout.

 

Ray

These are the Rock Molds, that I use on my layout.

  Click photo to enlarge.

Okay, I have more questions:

 

1. this rock is 2" concave, making a long curved wall.

 

2. is this going to be heavy enough that I'd be ahead just using the rock itself?

 

3. is there something lighter than POP or hydrocal?

 

4. as this is not going to be near the front of the layout what do you think about taking a full sized picture of it and mounting it on something light?

You can use a flat mold and make a curved surface.  All you need to do is press the mold against the curved surface before the plaster sets up.  Once the plaster has thickened up enough so it wont run out of the mold, pick it up and press it against your surface and hols it in place for a couple minutes to allow it to set.  After it sets, peal off the mold and paint.

Plaster sets in about 30 min. Depending on the curve, the casting may crack but that is not a didaster. I think structolite is lighter but it takes longer to set. This is a big mold you are making. If it sits back a little and the weigjt can be supported, use the rock. You can always add more. Don't forget the pictures!

Ray

Ray, What would it coast me to have you make me a mold like your brick walls and portholes?

Stuccolite is not very good for making molds.  It has a rough texture and wont reproduce the fine details of the casting.  As far as making molds of walls and portals.  All you need is a master to make a mold out of.  Follow the steps outlined above.  Pick up a item you want to copy and make a mold.  Plaster of paris is available in bags at the big box lumber yards.  Usually in the paint section.  Hydrocal can be found at a building supply center.  Call US Gypsum or one of the other companies to  locate a dealer in your area.

Mike

 

     It took me about two weeks to make a mold due to the overnight drying time for the latex. I have much business travel in the next two months and would not be able to do it. Its not hard you can do it and benefit from my learning mistakes.

Here is what I did.

     I used a piece of plexiglass for the surface to work on as it is flat and latex can be peeled off easily. For what ever you are copying, put it face down and wipe a border of latex around so it will not move. Keep the layers of latex thin, they cure better and will not contract when done. Let this dry overnight and the object will not move.

     Put thin layers each day till you have about 5 or 6 minimum. You can now put some mesh in the mold for strength. Make sure there are a few layers of latex between the mold and latex. I used 6 inch wide drywall mesh as it is self adhesive and stronger than gauze. Don't worry about folding down over the ends its over kill.

 

   Keep adding at least another 6 or more layers of latex to your mold. Don't worry about being too thick at the end as it will just be stronger.

 

     When you are happy it should just pop off the original. I used silicone caulk to level the back so it would sit flat on a surface when being used. I only have used Plaster of Paris because I wanted the quick cure time. Drywall mix may be faster but it is softer. You can do this its easy. Good luck and let us see your success.

 

By the way we have made over 100 from just two molds so far.

 

Ray Marion