mbelvadi
off to a rocking start
Member since November 2015
Posts: 11
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Post by mbelvadi on Dec 3, 2015 19:31:57 GMT -5
Hello, all. I'm new to this hobby and really appreciate all of the great posts from so many successful experienced tumbler-folks.
I have both rotary (12 lb Lortone and 3lb Thumler) and vibe (Raytech TV-10) tumblers, and went a little overboard mail-ordering different kinds of grit. I finally have some fairly hard rocks - jasper, quartz, feldspar, maybe agate - ready for pre-polish, and I'm wondering what the difference is between the AO 500 and SiC 500 in terms of the different kinds of tumblers for these kinds of rocks. Advice?
Thank you very much!
Melissa
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Dec 5, 2015 6:52:08 GMT -5
I've never used Aluminum oxide as a pre-polish, I always use Silicon carbide 500F (500 or finer). Both grits would be very hard (Moh's hardness 9 for AO, 9.1 or 9.3 for Silicon carbide, so no real difference. But AO tends to get rounded and smooth, whereas SiC is sharp and abrasive and breaks down into smaller but still sharp and abrasive bits as it gets crushed up in the barrel. So I guess it really depends on whether you want the pre-polish stage to do some fine grinding like with SiC, or whether you want it to start to polish things up as with AO. I always use SiC but I suppose AO might be better for certain materials (like maybe obsidian or other softer materials?). If you use AO, you probably want to run the pre-polish stage a bit longer than with SiC, as you won't get as aggressive a cutting action so will need more time.
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Post by Jugglerguy on Dec 5, 2015 8:03:30 GMT -5
I wonder If it makes a difference if you are using a rotary tumbler or a vibratory tumbler. I have never used SC at 500 grit. I use up through 220 and then switch to aluminum oxide at 500. I get good results this way in my Lot-O. After a couple days in 500 AO I start to get a pretty good shine. rollingstone, you use a rotary the whole way, right?
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Post by Drummond Island Rocks on Dec 5, 2015 9:01:42 GMT -5
I know this is not a very technical answer but when I first got started years ago I called Shawn at the Rock Shed and asked that question because he sells both and he steered my toward the A/O 500 for stage 3. It has always worked very well for me so I have never had a reason to question it. This is a batch of cabs I made after 2 days in 500 grit A/O in the loto Chuck
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jamesp
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Post by jamesp on Dec 5, 2015 9:15:09 GMT -5
Aluminum oxide is best for finishing since it rounds off, SiC for shaping since it cuts by breaking into sharper pieces.
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Post by Starguy on Dec 5, 2015 11:48:15 GMT -5
mbelvadiWelcome to RTH. Sounds like you're pretty serious about tumbling. You'll get lots of good advice here.
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mbelvadi
off to a rocking start
Member since November 2015
Posts: 11
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Post by mbelvadi on Dec 5, 2015 15:53:06 GMT -5
mbelvadi Welcome to RTH. Sounds like you're pretty serious about tumbling. You'll get lots of good advice here. Thank you! And thanks to everyone who replied so far. Drummond Island, those are beautiful! I hope I can get close to that someday. I get the impression from trying to combine everyone's answers that I might use the SiC 500 if I'm using the rotary tumbler for my third stage and happy to let the stones continue to be further rounded, and I should use the AO 500 in the vibe tumbler or when I just want them to get smoothed but not really shaped any more. Is that about right? Relatedly, after reading so many posts across RTH, I get the impression that despite the standard instructions from the manufacturers, I should be thinking in terms of 5 stages, not 4, or maybe even 6 (not counting burnishing), if I have really rough/uneven rocks, something like: 1. very low grit, like 30 or 46/70 SiC in rotary for 1-2 weeks 2. standard 60/90 SiC grit in rotary for 1-2 weeks 3. 110/220 SiC in vibe (assuming the shape is ready) for 4 days with refresh grit after 2; or in the rotary if shaping still needed, no refresh 4. AO 500 in vibe for 4 days with refresh grit after 2; or SiC 500 in the rotary if shaping still needed, no refresh 5. AO 1000 in vibe for 2 days 6. polish in vibe for 5 days with the possibility of skipping 5 if they come out of 4 already pretty shiny, and skipping 1 if the stones are already reasonably smooth, like beach stones. Everything I'm working with is very hard, typically Mohs 6.5 -7 stuff. Am I on the right track? Melissa
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rastageezer
starting to spend too much on rocks
Member since December 2013
Posts: 169
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Post by rastageezer on Dec 5, 2015 16:06:02 GMT -5
well.......some run 60/90 until and then polish......some have all kinds of burnish and prepolish......some toss all manner of stuff together and spin.....I'm thinking this ain't science.....however it probably is.
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Post by Jugglerguy on Dec 5, 2015 16:08:22 GMT -5
You don't need to use both 46/70 and 60/90. Use one or the other. By the time you take rocks out of the rough stage, 46/70 will have broken down to something finer than 60/90.
In the first stage, you have to get a set time out of your head. It's not 1-2 weeks or 2-3 weeks. You just leave them in there until they're done. In the best case it might take two weeks, but it's much, much more common to be a matter of months. When you do a clean out, inspect each rock and take out rocks that are done. To me, "done" means that there are no imperfections left at all. You might be more tolerant of imperfections, but if you leave holes, there's the chance that they might carry grit to a later stage and contaminate it. Don't fool yourself into thinking that small imperfections will be removed in later stages. Later stages will only remove scratches made by more coarse grit in earlier stages.
I do a lot of beach stones from Lake Superior. They are well rounded, but usually still have some holes that need to be removed. I've never skipped the first stage for beach stones, and they usually stay in the coarse stage for more than a couple weeks, but a few only take a week or two. The waiting gets easier.
When you go to the 120/220 or straight 220 stage in the vibe, you only need to run for about two days, no grit change or recharge necessary.
In the vibe, you can run 500 for two days and then move on, no recharge is necessary. I use AO, but I've never tried SC. AO works well for me.
I run a 1000 AO stage in my vibe, but I think it's only used for softer stones in a rotary.
I only run polish in my vibe for 2-3 days.
Except for the first stage and the 220 stage, I use 1 tablespoon of borax in each stage in my 4.5 lb. barrel. It kills plants, so be careful where you dispose of it. Don't put any rock slurry down your drain.
Rob
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rastageezer
starting to spend too much on rocks
Member since December 2013
Posts: 169
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Post by rastageezer on Dec 5, 2015 17:17:25 GMT -5
well that sounds about right to me
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mbelvadi
off to a rocking start
Member since November 2015
Posts: 11
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Post by mbelvadi on Dec 5, 2015 21:49:23 GMT -5
Wow, months!
What do you all think of the idea of using a wet tile saw to pre-smooth some of the nastiest spots (like rough indents that the other rocks likely won't be able to rub against and small but deep holes)?
I've been playing with it (made an awful rock-dust mess of my workroom, and yes I use a dust mask), but not sure how much time it saves me.
Would I get better results to let the more natural tumble process decide the shape instead of forcing lots of straight planes at various angles this way?
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Post by Jugglerguy on Dec 5, 2015 22:00:28 GMT -5
You can definitely speed things up by doing some pre-grinding. If there is a deep hole or a crack, you can also use a hammer and chisel to break the rock to expose the inside of a hole or eliminate a crack.
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Intheswamp
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Member since September 2015
Posts: 1,910
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Post by Intheswamp on Dec 5, 2015 22:12:11 GMT -5
Wow, months! What do you all think of the idea of using a wet tile saw to pre-smooth some of the nastiest spots (like rough indents that the other rocks likely won't be able to rub against and small but deep holes)? I've been playing with it (made an awful rock-dust mess of my workroom, and yes I use a dust mask), but not sure how much time it saves me. Would I get better results to let the more natural tumble process decide the shape instead of forcing lots of straight planes at various angles this way? Dust??? Are you cutting dry???
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Dec 6, 2015 4:18:30 GMT -5
Jugglerguy, you are right, I use rotary the entire way. Whether AO or SiC is best in pre-polish may well be dependent on whether you use a vibe or a rotary.
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mbelvadi
off to a rocking start
Member since November 2015
Posts: 11
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Post by mbelvadi on Dec 8, 2015 20:49:47 GMT -5
Intheswamp, I don't mean to be, but sometimes the bottom of the blade stops reaching the fill point of water pan and it takes me awhile to notice and refill it. I seem to have to refill it a lot, like every 2-5 minutes - is that normal for a 7" wet tile saw?
Jugglerguy, hammer and chisel, huh? I have to try that, but that means I have to, or well I get to, learn about chisels. One fun thing about this hobby is I'm learning about so many things along the way, like how to use vise grips (vibe tumbler nuts sometimes get seriously stuck on the metal screw pole), change blades on a tile saw, use diamond bits on a dremel to smooth out tiny imperfections, stuff like that. Any advice about kinds of hammers and kinds of chisels I should look for in the hardware store for this purpose would be most welcome.
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Post by Jugglerguy on Dec 8, 2015 20:57:47 GMT -5
You need to get a chisel for rock or concrete, not a wood chisel. You can get them with a hand guard if you want. I'd get a smallish one. I have a three pound sledge hammer to go with mine. When I chisel, I put the chisel through a hole in the bottom of an upside down Tupperware type container that goes over the rock. The plastic container contains all the rock chips so they don't go flying everywhere. I still use safety glasses. Don't do this on your concrete floor or driveway, unless you put something underneath to protect it. I use a piece of plywood. Otherwise your concrete will break easier than your rocks.
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Intheswamp
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Member since September 2015
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Post by Intheswamp on Dec 9, 2015 7:45:28 GMT -5
Intheswamp, I don't mean to be, but sometimes the bottom of the blade stops reaching the fill point of water pan and it takes me awhile to notice and refill it. I seem to have to refill it a lot, like every 2-5 minutes - is that normal for a 7" wet tile saw? I've no experience with a saw yet...I'm a newbie, too. What I was concerned about is that you might be inhaling the dust...which can cause silicosis . Which tile saw are you using? I bought a Harbor Freight one during Black Friday sales for $40 but haven't had a chance to use it. That is pretty quick water depletion but may very well be normal usage. Could you attach a water hose with a trickle of water coming from it to keep the water level more stable? Or maybe a 5-gallon bucket with a small valve installed in it to connect some tubing to...elevate the bucket higher than the saw and let it gravity feed into the saw's water reservoir? Best wishes.
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mbelvadi
off to a rocking start
Member since November 2015
Posts: 11
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Post by mbelvadi on Dec 9, 2015 21:30:26 GMT -5
Jugglerguy, thanks so much for the tips - you saved my concrete basement floor (aka foundation!) because I was indeed visualizing doing it on that! I love the tupperware idea too!
Intheswamp, I've never heard of silicosis before and I was stupid enough to breathe in quite a lot before I decided I should wear a dust mask. Sounds like I should check with my doctor to be safe (I'm in Canada, doc is free). You also gave me another great idea - I had been experimenting with camping "shower" bags this summer for washing my muddy dog at the park but it didn't work out. I'll bet I could hang that with the hose valve open a tiny bit to give a continuous drip into the saw pan!
I'm not sure of the saw brand - I bought it used from Kijiji, which is the Canadian version of Craig's list, I think. It takes standard 7" blades and I can get diamond ones for about $35 around here. I've worn out 3 so far.
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Intheswamp
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Member since September 2015
Posts: 1,910
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Post by Intheswamp on Dec 10, 2015 7:35:27 GMT -5
The shower-bag sounds like a possible solution to extend your run-time with your saw...give it a shot! Jugglerguy won't steer you wrong, he has good information and tips. How long did it take you to wear out three blades? My understanding is that running with no water and pushing/pressing the stone too hard against the blade will decrease the blade's useful life. Keeping the blade lubricated and maybe not pressing so hard might help increase blade life for you. Silicosis... I think developing silicosis is something that happens over time...an accumulation of silica in the lungs. Any silica inhaled isn't good for us but I feel that it's the concentrated amounts that are dangerous...we get some simply buy breathing in naturally occurring airborne dust but this is in slight amounts and *probably* doesn't affect us greatly unless we live in a very sandy/dusty area. Unless you've been dry grinding for a long time with no protection I wouldn't worry too terribly much about it. It kind of makes me wonder about folks living in deserts and other dry regions where natural silica dust might be abundant. But, I don't think any place would have more of it than in the presence of dry grinding/sawing of rock. Anyhow, don't fret over it, but do use caution going forward. Best wishes.
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mbelvadi
off to a rocking start
Member since November 2015
Posts: 11
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Post by mbelvadi on Dec 12, 2015 20:41:11 GMT -5
Thank you all for the advice, and I will be more careful about the dust!
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