The difference between plastic and rubber molds is very simple to understand:
•Rubber Molds start out as a LIQUID that hardens and forms to EVERY DETAIL of the stone surface.
•Plastic Molds starts out as a SOLID that is heated and warped into the MUTED SHAPE of the stone surface. Since Plastic Molds do not start out as a liquid it is IMPOSSIBLE to make an exact replica of a natural stone. This is the reason why stones made from plastic molds will always have muted textures of the natural stones they were made from.
Actually, most plastic mold companies do not use natural stone to make their molds. They typically use concrete stone that is already muted in texture and make a second hand copy of that. This is the worst of the worst in regards to stone quality and texture.
If you want to copy 100% of a natural stones detail you will have to use Rubber Molds, not plastic molds. Try it for yourself. Take a natural stone that has good detail like the stone in the picture below and use it to make one plastic mold and one rubber mold. Now, pour your concrete into each mold and compare the results for yourself.
Plastic Mold Pros
I will say that plastic molds are great for smooth brick type stones since they do not have too much detail to begin with. Plastic molds are also great to make spanish tiles since most tiles are smooth surfaced, without detail. Actually, I have plastic tile molds myself. But plastic molds are NOT going to make professional grade stone veneer, even if you make the molds directly from natural stone.
Do Your Own Research
You should do your own research if you are going to take stone veneer making seriously. Seeing is believing and talk is cheap. We suggest that you purchase a 1 square foot sample kit from us and a 1 square foot sample kit from a plastic mold company so you can make an informed choice. We are now offering the Rubber Mold Super Skin Starter Kit at $35 with shipping included. One square foot makes roughly 10 stones at time. Our Super Skins are the best of both worlds. With our Super Skins you get the lightness of Plastic Molds and the Detail of Rubber molds, at the same price as plastic. Our Super Skins are our answer to plastic molds.
Stone Square footage or Stone Pieces?
Make sure to ask your plastic mold distributor to verify how many square feet of stone veneer the mold kit will produce at one time. To say that they are selling molds based on the amount of individual stones the molds make is not logical. Mold kits that make 1 square foot of stone veneer may make 20 individual stones or make 10 individual stones but the stones will still cover the same amount of space, 1 square foot.
You can have 3 large stones that cover 1 square foot of space or you can have 50 small stones that cover 1 square foot of space. This is the reason why you should make sure to ask for the amount of square footage a mold kit makes because square footage is what counts, not "pieces".
Square footage is the unit of measure you will be selling your stones in, if you manufacture. Square footage is also the unit of measure that you will use to measure your home project, if you are a do it yourselfer. To measure in "pieces" is meaningless when it comes to stone veneer.