Batch 40: 36 Day Rock Tumbling Cycle

Batch 40 features stones from my local … Gemstone Beach but this poor batch was the forgotten batch with the 220grit rock tumbling cycle lasting a wopping 36 days!

The usual length of a tumbling cycle is 10-11 days give or take a few if life gets in the way but 36? That’s a new record for me! How on earth did that happen? Easy. When you forget to write in the calendar that barrel is due to be checked it’s super easy to overlook what a barrel is up to especially when you’re running 6 barrels! I need a calendar now because I’ve got six clipboards (a tumbling log for each barrel) hanging on the wall and it’s much easier to keep tabs on what needs dealing with when you use a calendar planner. (I stole this idea from my good rockhound buddy Nicola cos it’s such a brilliant idea!! Thanks Nic!) The planner works a treat UNLESS you forget to write completion dates in it in the first place!

Despite the slurry being a bit thicker than usual the rocks looked ok. No real harm done. In fact, it was probably jolly good for them! The 220grit rock tumbling cycle would usually grind about 100-110grams off a barrel load of stones so the 133gram loss recorded for Stage 2 seems about right!

Batch 40: 3lb Tumbler 4

Stage 1: 80/100grit

Number of Stones: 29
Weight in: 988g
4 Tbspns of 80/100grit
No Borax / No pellets
Days Tumbling: 10
Weight out: 887g – loss of 101g

Stage 2: 220grit

Number of Stones: 29-4=25
Weight in: 727g
4 Tbspns of 220grit
1 Tbspn Borax
Pellets added
Days Tumbling: 36 (Yikes!)
Weight out: 594g – loss of 133g

Stage 3: 400grit

Number of Stones: 25+1=26
Weight in: 605g
4 Tbspns of 400grit
1 Tbspn Borax
Pellets added
Days Tumbling: 10
Weight out: 498g – loss of 107g

Batch 40: Pre-tumble

B40 - pre tumble dry
Dry stones from Gemstone Beach before tumbling cycle begins
Batch 40 before polish
Batch 40 ready and waiting to be polished

Batch 40: After 36 Days!

B40 after 80/100grit
Top right hand corner – 4 stones removed for redo at 80/100grit

After Stage 3 (400grit) there wasn’t enough volume of stones to carry on to polish and I didn’t have any “readies” to add to help make up the load. I would need to use an awful lot of pellets to make the 2/3rd mark so this batch is now waiting in the polish holding box in a bit of water.

I have decided to try to get my hands on some ceramic pellets to add to the polish cycles to begin with. I’m not a huge fan of the plastic pellets for environmental reasons. I finally managed to find some on AliExpress (no one in New Zealand is selling these Oblique cylinder lapidary porcelain fillers). I hope I’ve ordered the right ones and I’ve ordered enough! They are not going to arrive until the end of the January – over a month since I first ordered them!

Transfer to 4lb Tumbler 1

This batch (26 stones) was added to Batch 41 and transferred to 4lb Tumbler 1 after waiting in water in the Polish Holding Box for a few days. It’s better if stones aren’t left to dry out, just incase there’s grit left in tiny pits or gouges that haven’t been smoothed out completely.

Stage 4: Polish Mix

Number of Stones: 26+124=150
Weight in: Didn’t weigh
Polish Mix (1st use): 9 Tbspns of polish mixed with 600mls of clean water. Plastic Pellets added.
Days Tumbling: 11
Weight out: 1689grams

Polish Complete: Batch 40 & Batch 41
Batch 41 (&Batch 40) complete

Polished Stones of Interest: Batch 40

SOI B40
Pretty pattern – Quartzite?
SOI b40
Rhyolite with crystal specks of quartz or feldspar (?)
SOI b40
I’m a sucker for black stones with white (quartz ?) veins

Batch 40 | 3lb Tumbler 4 | Gemstone Beach | 5 November – 31 December 2023
4lb Tumbler | Batch 40 & Batch 41 | Gemstone Beach (maybe some from Kakanui) | 3 January – 19 January 2024

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