I think I mentioned in this post that I was thinking about purchasing another Lortone twin tumbler from the Rock and Gemstone Shop in Rotorua. Well I did and the new Lortone Tumbler arrived with the twin barrels already underway with a load of stones in aptly named 3lb Tumbler Three and 3lb Tumbler Four (original names I know!)
I also purchased the Puluz Photo Light Box and that has been delivered already and is in action too! I love it! It’s perfect!
I put both new items to work almost immediately! The stones in Batch 20 are all from my fourth fossick with JP at Gemstone Beach on the 9th of April. 6 of the included stones are JP finds that he kindly gave me to tumble. I thought I’d track their progress and use the light box to take my before and after images.
New Lortone Twin Tumbler: 3lb Tumbler Three
Stage 1: 80/100grit
Number of Stones: 49+6=55
Collected from Gemstone Beach, 9 April, Fossick #4 with JP
Weight in: 1062g
4 Tbspns of 80/100grit – no pellets added.
Days Tumbling: 15 (longer than usual)
Weight out: 940g – loss of 122g
Stage 2: 220grit
Number of Stones: 55 + 1 – added a hydrogrossular that needs a little shaping
Weight in: 948g
4 Tbspns of 220grit – no pellets
Days Tumbling: 13 (longer than usual)
Weight out: 800g – loss of 148g
Stage 3: 400grit
Number of Stones: 56
Weight in: 800g
4 Tbspns of 400grit – pellets added.
Days Tumbling: 12
Weight out: 688g – loss of 112g
24 hour soap tumble before polishing stage.
Stones Removed
After inspecting all the stones after Stage 3 only two stones from this batch won’t be going through to polish. The little jasper (mentioned in detail below) will polish later but the stone to the right has been removed altogether. It has a deep gouge at the bottom and unfortunately it is too small to send back to 80/100grit to try and smooth that gouge out. That stone is now destined for the garden pots outside.
Tracking Progress
In this batch with the new Lortone Twin Tumbler barrel 3, I decided to track three jasper stones in this batch and use the light box to capture their progress through the tumbling and polishing stages. The jasper to the right ultimately didn’t make it into the polish mix as upon closer inspection, there were a couple of little pits at the very bottom – you can just make them out in the third image below.
This little one is now in the holding box with another stone from Batch 21 which I also took out because of a little pit. Later, I’m going to try these two at 600grit to see if those pits can be smoothed out without taking too much more of the stone’s shape away.
Transfer to 4lb Tumbler
Batch 20’s stones were transferred to the 4lb tumbler and combined with Batch 21 for Stage 4 and Stage 5 – polishing and burnishing (borax)
Stage 4: Polish
Number of Stones: 54 + 58
Weight in: 1292g
9 Tbspns of polish pre-mixed with 600mls of clean water. (This will be the 3rd use of this polish mix)
Days Tumbling: 10
Weight out: 1289g – loss of 3g
Stage 5: Borax
Final two days burnishing in 2Tbspns of borax for extra clean and shine.
Reflection on Finished Batch
I was not happy with the majority of stones in the combined tumble of Batch 20 and Batch 21. There were pits and/or cracks in almost all of the stones. I am pretty sure that this was a case of poor ratios. Either there was not enough content (stones and pellets) in the barrel or there wasn’t enough polish mix. Perhaps the stones were hitting each other too much causing the pits. The stones are checked closely before moving onto the polish stage so I would have seen pits. I don’t think that they were there before going into Stage 4.
This means I will need to pay more attention to the amount of stones and pellets/polish mix I put in the tumbler for the final stage. I have put the favourites back into the holding box to redo at 400grit to see if the pits can be smoothed out. Then they will be polished again.
Batch 20 | 3lb Tumbler 3 | Gemstone Beach | 2 June 2023 – 14 July 2023
4lb Tumbler | Batch 20 & Batch 21 | 14 July – 24 July 2023
The odd unsatisfactory batch tends to occur as you’re learning the process. Even now, after six years of tumbling, I have the occasional one where stone chipping occurs, though it is rare. Lately it might have happened because I am experimenting with using small stones as filler rather than plastic beads. Making small changes along the lines you have suggested is the right idea.