This is Part 4 In Our 5 Part "How To Polish Rocks Instructional Series". Be Sure To Check Out -
While rock tumbling is a test of patience, and that is part of the attraction for some, it is nice to get to the end and start to see the finished product. The Fine Rock Polishing Grind is one of the last steps in rock tumbling a batch of rocks. It is only followed by polishing and it is the first time a rock tumbling hobbyist will start to see the light at the end of the tunnel and the payoff for all the patience.
However, it is still possible to get things wrong that can make or break your entire batch. For that reason, we'll go over the steps involved in the find grind and set you on the right track to beautiful polished gemstones.
Once the medium grind is done and the stones have been inspected, it is time to prepare them for the fine grind. Load the tumbler with your rocks and add in your fine abrasive. For most rocks this will be an abrasive with a grit of around 550 – 600, much finer than any of the previous abrasives. While this abrasive may look like a powder, it is still a good cutting agent and will put the final tough on your stones.
Once again, as with the medium grind, if your tumbler is not filled up by the stones left in your inspected batch, you can use plastic filler to round out the mix and keep it tumbling correctly. Add enough filler to get the batch up to two thirds full in the tumbler, and then add your abrasive, baking soda, and a small amount of detergent to the mix. Add in your water to get the level of liquid to the top of the stones but not covering them completely.
Start your rock tumbler and let it run for 24 hours. After this time, you'll want to check to make sure that the stones have been tumbling properly and that the slurry mix is a good consistency. If needed, add abrasive or liquid to get it to a good viscosity.
While the fine grind usually lasts a week, you'll want to check some of the stones after a few days. Pull a couple out and see if they'll take a polish by hand. Just grab some polish and a piece of heavy felt. If you have a burnishing wheel or polishing wheel, that can be used too. Add a small amount of polish and see if the stones will polish to a high gloss shine. You may need to add a little bit of water to the polish to get it to move with enough action over the stone. Be sure to use a firm hand. Do not worry about damaging the stone, as it is still very hard and there is not much you can do to hurt it by hand. If you did gouge it, you could always grind that out in a fine grind tumble anyway.
If the stones will take a good polish to a high gloss, the fine grind has done its job. If not, you'll have to continue to run the fine grind until the stones will take a polish. After some experience, you'll know how long that takes for each particular type of stone and your particular rock tumbler. Until that time though, it is ok to stop the tumbler every few days and check a few by hand to see when they are ready to take a good polish.
It is very satisfying to get to the end of this grind. At this point, you can actually see a finished product level of shine just by putting a hand polish on your stones. Congratulations on reaching this level. If however you have some issues and need to run them through a longer fine grind, do not worry. Remember patience is a big part of rock tumbling and the final result will come.
This was Part 4 In Our 5 Part "How To Polish Rocks Instructional Series". Be Sure To Check Out -