Harbor Freight Tools 90979 - Manual (Page 7)

SKU 90979 For technical questions, please call 1-800-444-3353. Page 7
cracked stones. Place the stones in a plastic colander, or old nylon sock and rinse them
completely off. There should be no slurry or grit remaining on the stones.
IV-b. Second Grind:
Carefully replace stones into the Rubber Barrel (22). If the Rubber Barrel (22) is less
than 1/2 full, add plastic pellets (not included) to make up the difference. Add medium grit
(according to the measurements shown on the top of page 6) and water to the bottom of the
top layer of rocks. Reseal and tumble. Run it for 2-3 days before checking. They will begin to
smooth. After seven days they should have a smooth finish. If not, let them go another 2-3
days. Clean again as you did after grind one.
IV-c. Pre-polish:
Place stones into the Rubber Barrel (22) adding the correct amount of pre-polish and
plastic pellets (not included) if necessary, and water. Let it run for a week, checking every
other day. After a week take out 2-3 stones to test the progress. On a dampened piece of
leather, old rug, or towel, sprinkle a small amount of polishing compound, and rub the stone
vigorously with it. You should see a definite shine in a few moments. If they shine, clean the
Rubber Barrel (22) and you are ready for the last step. If not, continue to pre-polish and
check again in 24 hrs.
IV-d. Polish:
Gently set the stones in the Rubber Barrel (22) . Charge the tumbler with fresh water,
polishing compound, and plastic pellets to help cushion the stones. Make sure the volume is
at least 1/2 full, preferably 3/4 full. Tumble for 5 to 7 days. If they look the same dry as they do
wet, then they are finished. If they have a slight film, they need to be burnished.
IV-e. Burnishing:
Remove the stones, clean the Rubber Barrel (22) and remove and recover the plastic
pellets (set aside). Place the stones back in the Rubber Barrel (22) and replace the same
pellets. Use powdered soap such as
Ivory
®
or White King
®
(see chart on page 5) . Do not use
liquid detergents or dishwasher powders that have bleach. Add water as in previous steps
and seal the Rubber Barrel (22). Tumble for four days, and clean the barrel.
Notes to remember:
1. You must clean between steps.
2. When polishing or burnishing you must use plastic pellets (not included).
3. It is recommended to use a log book to keep track of each step.
4. If you start with stream worn or smooth stones, you may be able to eliminate the first
step.
5. It is advised that you purchase a mineral book which goes into more detail about
selection of stones for tumbling. As you learn about relative hardness of each stone
you will achieve greater success by not mixing soft and hard stones.
6. Always dispose of material properly.