Tumble and Polish

How I Use my Lortone Tumblers (Step-By-Step)

I currently have four Lortone Tumblers which gives me six tumbling barrels to use.

• 2 x Lortone 45C (4lb barrel tumblers – I was trying to use for polishing stages only but ended up having too many stones waiting to polish so now all barrels do all stages!)
• 2 x Lortone 33B Tumbler (twin 3lb barrel tumblers – I try to use for grit stages only)

If you’ve never used a tumbler before, they can be a bit loud. Think about finding a place in the garage or in a room away from your living/sleeping area where you can let your tumbler do its thing and not be too disruptive. My Lortone tumblers are reasonably quiet but I sit them on a rubber mat to help absorb some of the noise.

Beach stone tumbling is done in four different stages. A thorough cleaning of the barrel is absolutely necessary between each stage.  You need to remove ALL of the grit from the barrel and the stones. This is important before moving on to the next stage. What ever you do, DO NOT tip the grit slurry down your sink or drain. It will set like concrete and damage your pipes which will make for a very expensive visit from a plumber!

• About 45 to 55 small stones (up to about 2.5 to 3 cms each in size) will fit into a Lortone 3lb single barrel.
• Stones up to 4 cms big can be polished in the Lortone Model 45C barrel, and it can take about twice as many stones (so 90-110) as the 3lb barrel.

What You Need

• Rock Tumbler (personally I think Lortone Tumblers are the best!)
• Beach stones
• Grit
• Polish Mix or Alumina or Tin Oxide
• Plastic Pellets (dedicated batch for each stage)
• Water
• Grated Sunlight soap
• Borax

Stage 1: Shaping (Coarse: 80/100 grit)

The first step in tumbling is to shape with coarse grit.  All of the rough and sharp edges are mostly smoothed out during this stage.  This stage also helps to reshape stones to more round looking.

I fill the barrel about 2/3 full of stones. I have an acrylic stick with a 2/3 mark on it for both sized barrels and I try really hard not overfill or underfill my barrels. Next I add the coarse grit to the barrel. Read the manufacturer’s instructions for your tumbler. A good rule of thumb is 1 Tablespoon of coarse grit per pound of rocks/stones.  Be sure to weigh your rocks first!)

I do not add pellets or ceramic media to the first stage. You can if you want but is not necessary as you want those rocks to tumble against each other as much as possible to round off the sharp corners and smooth out those natural pits and gouges.

Finally, fill your barrel with just enough water to cover the stones. Close the lid.  Place the barrel on the tumbler and turn it on! In about 7-10 days I check on the progress of the stones.  Are they changing shape? Are they smoother? If so, then it’s time to move onto Stage 2 of the tumbling process.

Game Changer Update:

(April 2024) If you have been reading my blog posts lately you will have noticed that I haven’t been happy with the final results of many of the batches of stones I’ve been tumbling. After many hours of watching videos and lots of reading and researching I’ve made a number of changes to the actual tumbling process (updated on this page as I’ve changed) and I purchased this game changer equipment from Temu (it’s a cheap version but it sure does work beautifully for me!!) It’s called a Headband Magnifier and it was about NZD$26 – worth every.single.cent! This allows me to check all the stones after Stage 1 before moving them on to Stage 2. I can’t believe how much more closely I can inspect each stone! It’s a game changer! I’m using the 2.5x magnification lens at the moment and it works a treat.

Update to Tumbling Process:

I’ve started adding in 1 tablespoon (3lb tumbler) / 2 tablespoons (4lb tumbler) of borax with the grit cycles. The borax thickens the grit slurry which helps carry it around the stones in the tumbler. This article explains the use of borax quite well. I’m still testing this out and will update here once my testing is complete but so far I’m liking the use of borax in this way.

I am not soap tumbling in between stages anymore either. I do still soap tumble for 24 hours after Stage 3 (400grit) before the stones go into the tumble polish mix though.

Stage 2: Smoothing (Medium: 220 grit)

Soap tumble: Thoroughly clean out all of the coarse grit out of the barrel. Rinse off all of the stones. Put a couple of pinches of grated sunlight soap into the tumbler (with the stones & pellets) and complete a 3-24 hour soap tumble. This helps to ensure that all grit is completely removed. You’ll be amazed as just how much more grit comes out in a soap tumble! If grit transfers to the next stage, especially coarse grit, it can scratch your stones.
HandyTip: Grate the bars of sunlight soap and store in a plastic container. Add just a few gratings to a washed batch of stones after each tumble.

Once the soap tumble is finished I inspect the stones carefully and remove any that look like they need to repeat the coarse grit stage again. I’ll put those stones in a holding box to wait until another load of stones is ready to go through Stage 1.

Repeating the same process as before, except this time using medium (220) grit and plastic pellets. (I have pellets that I only use with 220grit to help minimise cross-contamination). Pellets help cushion and protect the stones from hitting each other.  This stage of the tumbling process will remove any scratches, cracks or dimples that might be visible on the stones.

Stage 3: Pre-Polish (Fine: 400 grit)

After another thorough cleaning, rinsing and 3-24 hours in a soap tumble, the stones should be ready for Stage 3. It is exactly the same process as before except we’re using 400 grit. I also have dedicated plastic pellets for use with 400grit only.  

This stage also takes about a week to 10 days. I use 4 level tablespoons of grit for the 3lb tumbler or 7 level tablespoons of grit for the 4lb tumbler.

Sometimes stones (especially hydrogrossulars which I find quite regularly at Gemstone Beach) don’t need Stage 1-3 as they are already quite smooth. These stones can tumble in very fine 600 grit instead before going into Stage 4 – polishing.

After your final barrel cleaning, rinsing and 3-24 hours in a soap tumble (an absolute must BEFORE you polish as you do not want any grit contamination in the polish stage) you’re finally ready for the polishing stage!  

Stage 4: Polishing (Polish Mix)

You MUST use plastic pellets/ceramic media during this stage! They prevent your stones from hitting against each other and ruining all of the hard work you’ve put in so far. I have pellets that I only use for the polishing mix. Consider using a dedicated barrel for polishing only as this will help with reducing grit cross-contamination.

The tumble polish powder needs to be mixed with water before being put into the tumbler barrel with stones. I use an 800ml Sistema shaker to mix it. This tumble polish mix (it’s aluminium oxide) can be re-used up to six times as it takes longer to lose its effect. (I use it at least 3 times but if it starts to look grey then I’ll tip it out and start a new mix). It does not wear away the stones and thus lose it’s “activeness” like grit does. Watch for cross-contamination. Use a clean plastic bucket with the shaker inside it to collect the mix after the tumble polish. Write the date the mix was used on the side of the shaker so you can keep track of how many times you’ve reused the tumble polish.

After a week to 10 days at this stage, your stones should come out looking shiny even when they are dry.

Polish Mix Alternatives

Update (April 2024): Polishing powder alternatives such as Alumina from cdkstone.co.nz can be used instead of the Polishing Mix. Enquiries about the grit rating for Alumina (or Polyal-1) have come back as 1000 grit. This isn’t as high as other rock tumbler-persons suggest you need. The recommendation for a polish compound is that it is at least 8000grit right up to 12000grit. Therefore the alumina would be considered a Pre-Polish. I haven’t used it yet as I’m quite happy with the Tumble Polish Mix mentioned above.
Tin oxide or Cerium Oxide are other polishing alternatives. As I haven’t used them, I am unable to rate their quality.

Stage 5: Burnishing (Borax)

This fifth and final step is referred to as burnishing. It entails immersing the stones in a “heavy soap bath”. I use borax for this and I let the stones tumble for 48 hours in borax and water.

Although most tumbled stones look pretty good at the end of Stage 4 (Polishing) this step, in most cases, can significantly improve their lustre and make them truly shine.

Place your polished stones in a cleaned out tumbler barrel. Make sure the barrel is about two-thirds full so the stones aren’t tumbling too much against each other. If you don’t have enough material to fill the barrel add clean plastic pellets. If you need to add cushioning between the stones, add clean plastic pellets. (I have dedicated plastic pellets for Borax only). The burnishing step should be a nice and gentle tumble.

Other Handy Tips & Links

Tumbling Stages

STAGE	DAYS Tumbling	3lb Barrel	4lb Barrel
Pretumble	Stone Collection	45-55 sm/med stones	90-110 sm/med stones
Stage 1	Coarse: 80/100 grit, 7+ days	4 Tbspns	7 Tbspns
(Optional)	Soap Tumble: 3-24 hours	(I don’t do this anymore)
Stage 2	Medium: 220 grit, 7+ days	4 Tbspns	7 Tbspns
(Optional)	Soap Tumble: 3-24 hours	(I don’t do this anymore)
Stage 3	Fine: 400 grit, 7+ days	4 Tbspns	7 Tbspns
(Must)	Soap tumble: 3-24 hours
Stage 3a	Very Fine: 600 grit, 7+ days	4 Tbspns	7 Tbspns
Stage 4	Polishing: Polish Mix, 7+ (10) days	4 Tbspns + 300ml water	9 Tbspns + 600ml water
Stage 5	Burnishing: Borax, 2 days	1 Tbspn	2 Tbspns

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