How To Break Up Rock for Tumbling
If the rocks you have are larger than you'd like (or need) for tumbling or other uses, here are some hints for breaking them up into smaller pieces:
- For most tumblers, it's best to have a mix of sizes from 1/2" to 1" in diameter, with more small rocks than large. For the QT6 and up, you can use rocks up to 3" in diameter (but still include smaller sizes for best results).
- Always wear safety glasses and gloves when breaking up rocks. Children should be supervised.
- Put the rocks in a heavy bag - we recommend canvas, but a pillowcase will do - before wielding your hammer. This will protect you from flying shards and keep the smaller pieces from being lost. Rocks of different hardnesses should be broken (and tumbled) separately, or the softer rocks will be crumbled by the harder ones.
- A crack hammer works best for large rocks. For smaller rocks, a rock hammer/pick or household hammer will work fine. Put the bag of rocks on a firm surface (concrete or asphalt), and knock gently. Slowly apply more pressure, until you feel the rocks start to break. Check your progress, remove rocks that are already small enough, then continue.
- Your broken rocks may have sharp edges -- be careful and wear gloves when you remove them from the bag.
- Very soft rocks -- like soapstone, alabaster, and pipestone -- are usually not tumbled. If you need to break them up for carving small items, it's probably okay to do so without a bag. Put them on a firm surface and knock very gently, preferably with a chisel. Look for a natural fissure, and work with that for best results.
- A gentle hand is always best -- too much force may splinter your rock into pieces that are too small to tumble.
- Estwing crack hammers, hammer/chisels, and hammer/chisels are the best tool for rockhounding; they are made to be used for years and years.
When in doubt, we're always here to help! Call us toll-free at 1-877-WE ROCK U, or email us.