Next, add water to the top of the stones. Measure the proper amount of abrasive and put it in. Put the top on the barrel and start it in motion. This stage will take about a week. However, you should open the barrel and inspect your stones every day.
Some stones release gases that build up inside the barrel.
Simply opening it every day is enough to eliminate this problem. You also need to keep track of your progress. The only way to do this is to take a few stones out, rinse them off and have a look at them. The waste from your tumbler can plug up a drain. When your stones are all nicely rounded and have no angular surfaces left, it is time for the next stage.