How to Make Rock Wall Hand Holds Using ComposiMold

Here is an inexpensive way to make hand holds or fake rocks for rock climbing walls.

Here are some directions to make handholds using ComposiMold reusable mold making compound. Below is an image of some the fake rocks I made. Can you find the originals? I used several different resins and fillers: polyurethane/silica, polyurethane/sand/gravel, epoxy/sand/gravel, and cement (quicksetting)/ sand/gravel.

Figure 1. Examples of Rock Climbing Hand Holds using ComposiMold

Start with these supplies:

• A rock that you want to duplicate, or use a piece of play-dough that is dried (or for the really expensive-a piece of clay) to make the shape that you want.

• ComposiMold, any kind will do. I will show you using ComposiMold-LT. ComposiMold-Transparent may be nice so you can see the rock inside it. The difference between the two materials is ComposiMold-LT is a stiffer rubber whereas the ComposiMold-Transparent is easier to see through.

• A container to put the mold material in. I am going to use a plastic container (cheap Tupperware container) for these parts. You can also use aluminum foil for the mold. Typically you can use 3 or 4 layers of aluminum foil stacked together and the edges folded up to make the sides. Be sure to make the sides high enough.

• Mold release. I am using vegetable oil brushed lightly. I am also using a universal mold release.

• A resin to make the mold. I am going to show you polyurethane, epoxy, and cement. Another inexpensive version would be polyester, but I did not want to deal with the smell. Cement is great, but the hand holds are cold on the hands.

• A filler to add to the resin. I will use sand, gravel, and micro balloons, and sawdust. These are used so I don't have to use as much resin and the parts are less expensive. The resin is the only expensive part of this process.

• Bolts and washer to attach the fake rock to your wall. 3/8" has plenty of strength.

1. Prepare your rock to be molded.

Put mold release on the fake rock to be molded. Here I am using vegetable oil and universal mold release spray. Place fake rocks to be molded into containers

Figure 2. Place Rock Into Container Prior to Covering with the Mold Making Material

2. Melt ComposiMold.

I melted the mold making material in the microwave. Every microwave is going to be different-watch the ComposiMold as it melts to make sure it does not bubble or the container does not melt. For me, using a 32 oz container, I placed it in the microwave for 2 minutes, stirred it a little around the edges and let it sit for 1 minute. I then put it back in the microwave for another 1 minute 30 seconds, stirred it, and let it sit for another minute. Another minute and 30 seconds in the microwave, and then I stirred it again. I then let it sit for about 5 minutes. This allowed the temperature to equilibrate to all of the resin.  Total time to melt was 12 minutes. I did this at the same time as I prepared the rocks.

Figure 3. Melt ComposiMold Reusable Mold Making Material in Microwave

3. Pour ComposiMold over fake rocks to be molded.

Don't worry about using all the ComposiMold. You can re-melt it afterwards and reuse it when you want.

Figure 4. Pour the Reusable Mold Making Material Over the Rock

4. Let Molds cool.

You can make it cool faster in the refrigerator or freezer. It took my molds about an hour in the refrigerator. Below is an image of two of the rock molds I made.

Figure 5. Formed Rock Molds using ComposiMold

5. Remove the rocks from the ComposiMold

Figure 6. Pull Rocks from Solidified ComposiMold

6. Mix resins and fillers and pour into molds.

Just in case-re-apply a little mold release to the inside of the molds. You may not need to, but it can't really hurt. For ease of use, I typically keep the resin flowable so it still goes into the mold easily.

Figure 7. Pour Resin/Filler into ComposiMold Molds

7. Place bolts and washer into resin/fillers.

I held them in place until the resin cured. In figure 8 left, I placed the bolt facing upward with a bolt inside the resin to give better grip. In figure 8 right, I placed a nut and washer on the end of the bolt. After the resin cured, I unscrewed the bolt with pliers.

Figure 8. Add Bolts to Resin/Filler

8. Let Resin Cure.

Be sure the resin has cooled before removing from the ComposiMold so you don't damage the mold.

Figure 9. Resin Curing in ComposiMold Mold

9. Remove from mold and make more.

When you are ready to move onto other shapes and size molds, re-melt the ComposiMold and start again. One real rock is the pink rock and the other real rock is in the top right corner above the white plastic rock.

Figure 10. Examples of Rock Climbing Rocks Made in ComposiMold Mold

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