I recently got my hands on a second-hand, hardly-used QT12 Lortone Tumbler thanks in part to my good friend JP who put me in touch with the seller of this whopper tumbler!
Included with the QT12 tumbler came a second 12lb barrel (previously only used for polish) and some extra grit including a rather large bag of F60grit plus a bag of Pro-Polish Mix.
After checking with the knowledgable and very helpful Colin from The Rock & Gemstone Shop in Rotorua, it was confirmed that with the pro-polish mix you will need to use 600 grit before hand then use the pro polish as your final polish. Otherwise you need to use the pro-polish as the stage before the Tumble Polish if you don’t want to purchase 600 grit. Colin also said that the tumbling medias have changed in the last 2 years and pre polish or pro polish aren’t manufactured any longer. These are the alternative ways you can use up your pro-polish.
First Barrel Load
The manual that came with the QT12 tumbler stated 20 Tbspns of grit for ⅔ barrel load. That’s quite a lot of grit but I gave it go any way! I think it was overkill but the stones lost 938 grams of volume!
On the 23 March after 11 days tumbling the first load of stones (all from Gemstone Beach) finished their tumble in F60 grit.
There were 235 stones in that load weighing 4325 grams. No pellets added as Stage 1 is where the most shaping and smoothing out happens with the coarsest grit. 938 grams was lost in this stage.
Second Barrel Load
Out of the 235 stones only 25 stones needed redoing. 210 stones went into the readies holding drawer (for Stage 2). I added some more rough stones to the barrel to do another F60grit tumble. All of the new stones added came from a fossick I did down at Gemstone Beach with JP on the 15 March. There are some really cool, different-looking stones in this load!
Rather than using the manual recommended amount of grit I added 1 Tbspn per lb of stones and one more for luck! 207 stones = 4219 grams which = 11 Tbspns of F60grit. After 12 days the stones lost 1657 grams of volume.
I’d used less grit, tumbled for 2 days more, had a few less stones which resulted in more volume lost from the stones than the first load I did. This tells me that I have been using more grit than I really need to in my tumbling process.
Third Barrel Load
After two rounds of F60 grit (with two different loads of stones) there was enough stones to do a 12lb barrel load of 220grit. Sticking to the same amount of grit (1 Tbspn per lb of stones) 10 Tbspns of 220grit was added, along with 2 Tbspns of borax (to help thicken the slurry) and some ceramic pellets. After 10 days of tumbling the stones only lost 420 grams of volume. A 3lb barrel load usually loses about 100-120 grams of volume during Stage 2 so this loss amount seems about right.
Rather than continue with Stage 3 in the 12lb barrel all the readies went into the readies drawer for 400grit – Stage 3. Another 190 stones from Gemstone Beach (from the fossick with JP) started their tumbling journey in the QT12 tumbler. Again, 10 Tbspns of F60grit was added to the load, along with 2 Tbspns of borax but no ceramic media. 10 days later the stones had lost 759 grams of volume. 72 of the 190 stones were not ready to move to Stage 2. 118 stones were placed in the readies drawer for 220grit.
Fourth Barrel Load (Batch 60)
The 12lb barrel went on F60 (Stage 1) duty again. This time with the 72 stones that weren’t ready to move to Stage 2 plus 188 stones from Gemstone Beach (14/15 April). These were picked up during a couple of fossicks with Shona and Lee – two lovely ladies from the North Island that I’d met down at Gemstone Beach. After 11 days tumbling, this load of stones lost 870grams in volume. Some stones went out to the garden pots as they weren’t suitable for carrying on. Some were too small to go any further (even polishing) so I put those in my filler jar. Sometimes when I don’t have enough ceramic media available I use the little stones as filler or cushioning.
The readies from this load went onto 220grit and became Batch 60.
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