Tumbling cut slabs?

[Warzy Raptor]

Got a question for the more experienced tumblers - I absolutely LOVE to sit outside with my saw and cut slabs, but good lord at the rate I do it I definitely do not have the time to sit there and hand-polish them all lmao.

Anybody have experience with tumbling slabs that can impart some wisdom on me? (Obviously this just applies to ones that are tumbler-sized; I’m running 3lb barrels.) I want to prevent breakage if I can (though some of my earlier ones I did cut pretty thin so I won’t be mad if they do break) - would they do all right in a vibratory from Stages 2-4 with ceramic media, or should I stick to rotary? And would Stage 2 be enough to remove saw marks, or should I definitely run them in Stage 1 first - OR could I alternately hit the surfaces that I want to take a good polish with a 220grit flat lap disc, and then put them directly into Stage 2? I’m not trying to do any shaping at all, just give them a nice shine

Thanks in advance!

[HankRocks]

 Warzy Raptor Yes you can polish slabs in a tumbler. I Have a batch of about 100 - 2 to 3 inch slabs in a Model B running 500 AO pre-polish. Will finish them in a UV-18 Vib tumbler. All previous stages were in the Model B rotary

First is you will need some cushioning smalls, pea gravel of saw scraps will work nicely and they also help with the surface contact grinding. I do look and grind down any large nubs if they exist on any of the slabs. I also use less grit in all of the stages as the action with slabs is less than a regular load of rocks maybe half the grit.

Make sure that none your slabs can be a large enough to cause a jam and restrict tumbling action, maybe half the barrel diameter and depth. No exact figure but I think you can figure that out. 

Make sure slabs are the heaviest rocks in the batch. A round 1 to 2 inch rock will reek havoc on the slabs. 

I do lose a few slabs to breakage but that is usually due to pre-existing fractures.

Good luck

Hopefully I will post some pictures of my small slab batch in a couple weeks.

Henry

[Warzy Raptor]

Aug 10, 2024 16:00:27 GMT -5 HankRocks said:

 Warzy Raptor Yes you can polish slabs in a tumbler. I Have a batch of about 100 - 2 to 3 inch slabs in a Model B running 500 AO pre-polish. Will finish them in a UV-18 Vib tumbler. All previous stages were in the Model B rotary

First is you will need some cushioning smalls, pea gravel of saw scraps will work nicely and they also help with the surface contact grinding. I do look and grind down any large nubs if they exist on any of the slabs. I also use less grit in all of the stages as the action with slabs is less than a regular load of rocks maybe half the grit.

Make sure that none your slabs can be a large enough to cause a jam and restrict tumbling action, maybe half the barrel diameter and depth. No exact figure but I think you can figure that out. 

Make sure slabs are the heaviest rocks in the batch. A round 1 to 2 inch rock will reek havoc on the slabs. 

I do lose a few slabs to breakage but that is usually due to pre-existing fractures.

Good luck

Hopefully I will post some pictures of my small slab batch in a couple weeks.

Henry

Excellent, thanks friend! I was thinking of doing a batch that was solely slabs just to test it out, the good lord knows I have enough of them to experiment with (and I’m gonna have some more after I do some cutting tonight!) Will definitely use some pea gravel - I think I actually have a ton of it leftover from when I had aquariums.

[Starguy]

I use a glass cutter to reduce larger slabs down to tumbling size. It doesn’t work on every type of rock but you can get some nice shapes. Even very delicate looking agate pieces usually tumble just fine. After they’re scored, I put the slab in a small vice to break it on the lines. You can make a lot of tumbler feed quickly that way. Slabettes of 2-3 square inches go in whole. I do all of my tumbling by rotary methods.

[velodromed]

Aug 10, 2024 14:37:36 GMT -5 Warzy Raptor said:

Got a question for the more experienced tumblers - I absolutely LOVE to sit outside with my saw and cut slabs, but good lord at the rate I do it I definitely do not have the time to sit there and hand-polish them all lmao.

Anybody have experience with tumbling slabs that can impart some wisdom on me? (Obviously this just applies to ones that are tumbler-sized; I’m running 3lb barrels.) I want to prevent breakage if I can (though some of my earlier ones I did cut pretty thin so I won’t be mad if they do break) - would they do all right in a vibratory from Stages 2-4 with ceramic media, or should I stick to rotary? And would Stage 2 be enough to remove saw marks, or should I definitely run them in Stage 1 first - OR could I alternately hit the surfaces that I want to take a good polish with a 220grit flat lap disc, and then put them directly into Stage 2? I’m not trying to do any shaping at all, just give them a nice shine

Thanks in advance!

I also enjoy cutting small slabs (usually 3 to 5 inches) and since I can’t hand polish at this time, I run all of them through either my 3 pound barrels or, more often, my raytech five vibratory. There is some chipping and occasional breaking, but most make it through and I love how they look afterwards. I have A batch that I’ve been working on for a couple of weeks now that I’m excited about pulling out soon.

Basically, if the slabs are rough and there’s a lot of saw marks I will run them through 60/90 grit in my 3 pound barrel for a few weeks. Then go to the vibratory to finish up. But if they do not have a lot of saw marks then they go straight to the vibratory for however long they need. If I have a chance, I’ll post some pictures later.

[nowyo]

Do it all the time. @hankrocks has it down. I do all rotary, tumbling mostly 1/8" thick slabs. Lots of smalls, key for me seems to be fight the urge to overload your tumbler. Those slabs need to be able to move. Doing this in 5C and QT6 Lortone tumblers. Usually go straight to pre-polish, if making something with a live edge I'll run them in 120/220 first to "soften" the edge.

Russ

[stefan]

Yes I do it too. All of my endcuts and odd balls, and stuff that will never be cabbed. I use the rotaries for them. I will finish them off in the mini sonic sometimes. The trick is to maintain that good mix. Too many slabs and they will tend to stick together. Sometimes if you try just one or 2 they will get beat up, but usually it is ok.