tkvancil
fully equipped rock polisher
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Post by tkvancil on Dec 13, 2013 13:57:51 GMT -5
On Tuesday the 10th I went down to my rock room to clean out a batch running in 220 and move it to 600. I heard a noise coming from the tumblers I'd never heard before. Gas had built up and pushed the lid liner up to the top of the barrel lip. The knurled nut was hanging on by about a thread or two and tapping the tumbler frame as it rotated. The barrel looked like this.... and this was where the liner had gotten to.... The rocks in the barrel are mixed rough from the rock shed. Nice stuff by the way. Some of it is petrified wood which I assume would be the most likely source of the gas. I've had this happen a few times lately in my 220 runs. The previous culprits were stamatolite and a couple stones that I can't ID but have what look like metallic mineral inclusions. I never noticed bas build up in my 60/90 cycle which I do almost exclusively in my QT66. I clean out every 5 to 7 days on those. I do the following steps in my 33B's. I run 220 and 600 for 10 days at a time and polish for two weeks. Again I'm assuming that the extra time contributes to gas build up. I've tried two things to prevent gas. First is baking soda. DON'T use it , at least in lortones, I nearly had a barrel "explode" after only a day. The second , borax, which seems to work reasonably well. I'd be curious to know what types of rock have caused other members to get gas build up and what they use to help prevent it.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
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Post by quartz on Dec 13, 2013 14:33:46 GMT -5
Everything I've had gas troubles with has had some sort of metallic content, be it a rusty appearance, silvery like hematite, or the time I thought it smart to jumpstart the slurry with scraping from the vibe lap, a tiny bit of aluminum. I ran across an article some time back that explained the metallic reaction, but can't find it again. Obsidian always gives me fits too. I put in a couple tbs. borax at each cycle, seems to help except w/obsidian.
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Post by pghram on Dec 13, 2013 16:47:05 GMT -5
That's a good catch, you almost had a huge mess on you hands.
Rich
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jamesp
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Member since October 2012
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Post by jamesp on Dec 13, 2013 22:19:05 GMT -5
Good luck. I had good with sugar. About a cup per 3 pounds of rock. It seems to calm bubble production. And calm the belly of the rotary tumbler.
Have polished many loads w/same sugar dose. Sugar serves as a cutting and tumbling lubricant too. I have never had gas w/sugar. It makes the slurry a bit syrupy.
A barrel of stones in polish and sugar allows your hand to be thrust into the stones like a barrel of seeds. i.e. it allows very free sliding = lubrication. Delicate stones are tumbled in higher doses of sugar to serve as the ultimate padding. Hard to have much hitting action if stones are in syrup.
good luck. try bottled water or different water. i have much more gas in the winter. i think because i use old water stored in a drum as the water supply is turned off to avoid freeze.
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Post by nowyo on Dec 15, 2013 0:25:19 GMT -5
So far, I've only had that problem with obsidian. First time I tried running that, it actually pushed the lid off and spewed snot all over. Since then, on that kind of material I just go "burp" the barrel every couple of days. Haven't run that much metallic stuff, but if your water/slurry is a little bit basic, I can see it reacting with something like aluminum to build up gassing. An acidic environment would do the same with ferrous materials.
Russ
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jamesp
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Post by jamesp on Dec 15, 2013 4:47:02 GMT -5
So far, I've only had that problem with obsidian. First time I tried running that, it actually pushed the lid off and spewed snot all over. Since then, on that kind of material I just go "burp" the barrel every couple of days. Haven't run that much metallic stuff, but if your water/slurry is a little bit basic, I can see it reacting with something like aluminum to build up gassing. An acidic environment would do the same with ferrous materials. Russ I believe acid/alkaline has lot to do w/gas as you would imagine. The water sources i have are varied. PH 6, 6.7 and 7.8. The PH 6 from the aquatic plant pond is used in the winter and foams a lot. Not saying that it is due to the low PH but sure makes sense. The coral i tumble is obviously lime. Acid water should bubble and fizzle for sure when they come together.
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tkvancil
fully equipped rock polisher
Member since September 2011
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Post by tkvancil on Dec 15, 2013 10:55:01 GMT -5
Everything I've had gas troubles with has had some sort of metallic content, be it a rusty appearance, silvery like hematite, or the time I thought it smart to jumpstart the slurry with scraping from the vibe lap, a tiny bit of aluminum. I ran across an article some time back that explained the metallic reaction, but can't find it again. Obsidian always gives me fits too. I put in a couple tbs. borax at each cycle, seems to help except w/obsidian. Okay...so we got a confirm on metallic content. It was a surprise to me in the recent batch it occurred in. I'd done some lace before which had streaks of hematite in it with no problem. Thanks for the feedback.
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tkvancil
fully equipped rock polisher
Member since September 2011
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Post by tkvancil on Dec 15, 2013 11:17:51 GMT -5
Good luck. I had good with sugar. About a cup per 3 pounds of rock. It seems to calm bubble production. And calm the belly of the rotary tumbler. Have polished many loads w/same sugar dose. Sugar serves as a cutting and tumbling lubricant too. I have never had gas w/sugar. It makes the slurry a bit syrupy. A barrel of stones in polish and sugar allows your hand to be thrust into the stones like a barrel of seeds. i.e. it allows very free sliding = lubrication. Delicate stones are tumbled in higher doses of sugar to serve as the ultimate padding. Hard to have much hitting action if stones are in syrup. good luck. try bottled water or different water. i have much more gas in the winter. i think because i use old water stored in a drum as the water supply is turned off to avoid freeze. When I first started tumbling I read about sugar in polish being helpful but have never tried it. From some of your posts I've read I know that it works great for you. I remember another forum member's post about using syrup in rough grind with explosive results. Water could be a contributor here, our tap water has some lime/calcium. Usually I get it hot from the tap but I think in this batch I put in some that had been sitting in a container for a while.
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Jasper-hound
starting to spend too much on rocks
Member since June 2010
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Post by Jasper-hound on Dec 15, 2013 11:29:03 GMT -5
I don't know how to prevent the problem, but I actually wore out the bottom of a Lortone barrel that was swollen like that; wore the rubber very thin on the bottom.
New little barrels are not cheap either!
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jamesp
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Post by jamesp on Dec 15, 2013 11:32:02 GMT -5
I try to not store any fluids from the tumbler and reuse. I think a lot of people do though. I have had bad smells and then gas build up from old solution.
My tumblers are in a greenhouse and there is stagnant water all over the place. I scoop it into the tumbler.(only in the winter) It is way worse about foaming. But it could be the
fertilizer in the water too. It is all very technical. But i have regularly had foam from that more acidic water. The rough grind is always the worst about gas.
I am always tumbling the same rock too. Which reduces variables a bit.
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jamesp
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Member since October 2012
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Post by jamesp on Dec 15, 2013 11:33:44 GMT -5
Everything I've had gas troubles with has had some sort of metallic content, be it a rusty appearance, silvery like hematite, or the time I thought it smart to jumpstart the slurry with scraping from the vibe lap, a tiny bit of aluminum. I ran across an article some time back that explained the metallic reaction, but can't find it again. Obsidian always gives me fits too. I put in a couple tbs. borax at each cycle, seems to help except w/obsidian. And almost always i have silvery bubbles and slurry. Sometimes it is brown . hmmm
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quartz
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breakin' rocks in the hot sun
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Post by quartz on Dec 15, 2013 22:34:41 GMT -5
I think from reading this, water may well have an effect on the gas formation, be interesting to have a bunch of people test Ph before and after running a batch. Especially those running on well water. Our water is neutral, and some batches I've tested stay near neutral, some go off the chart base. Now, I have to pay attention to any gas association, haven't done that yet. Then too, since putting a couple tbs. borax in the barrels, I haven't had any real gas buildup. Going to add another column to by little log. I hope this discussion gets a lot more comment. Larry
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jamesp
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Post by jamesp on Dec 16, 2013 0:22:34 GMT -5
This is a technical one since the rocks we grind can have so many crazy chemicals/metals/ph's etc.
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Post by Starguy on Jan 22, 2014 22:00:18 GMT -5
I've had problems with obsidian and glass. Who would guess. I think the problem is tiny bubbles of compressed gasses in the glass/glass-like stones. Try warming the stones, grit, barrel and water before loading the barrel. Put the lid on and let the warm ingredients warm the air in the barrel for a few minutes. Then seal the barrel and let it cool. The cooling air in the barrel should create a slight vacuum actually causing the bottom of the barrel to pull in a little.
It can lead to a little faster wear on the bottom of the barrel, but it allows for expansion of the barrel from released gasses. I had a top pop off a 12 lb barrel one time. I definitely don't want that mess again.
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Post by pauls on Jan 23, 2014 2:24:17 GMT -5
As far as I know the gas in tumblers is Acetylene from the decomposition of Silicon Carbide. Carbide which was used to generate acetylene gas for lighting many moons ago is Calcium Carbide. Its a long time since I did chemistry, and who knows what chemicals are being cooked up in the sludge in a tumbler barrel but Calcium Carbide could easily be a product in there, even if only momentarily.
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tkvancil
fully equipped rock polisher
Member since September 2011
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Post by tkvancil on Jan 23, 2014 12:03:02 GMT -5
I've had problems with obsidian and glass. Who would guess. I think the problem is tiny bubbles of compressed gasses in the glass/glass-like stones. Try warming the stones, grit, barrel and water before loading the barrel. Put the lid on and let the warm ingredients warm the air in the barrel for a few minutes. Then seal the barrel and let it cool. The cooling air in the barrel should create a slight vacuum actually causing the bottom of the barrel to pull in a little. It can lead to a little faster wear on the bottom of the barrel, but it allows for expansion of the barrel from released gasses. I had a top pop off a 12 lb barrel one time. I definitely don't want that mess again. Normally I do use hot water, as hot as the tap will run. I also let the rocks sit in the hot water for a while in a separate container before putting them in the barrel. Don't remember why but did not do so in this 220 run. When this batch went to 600 I used hot water and a tablespoon of borax in a 3# barrel and got no gas build up. Pics of the finished rocks are now in the Totally Rock Tumbling Photos section (Mix Rough with "Hamrock"). I should stick to using hot water , it's a good tip. Almost two weeks week ago I started a batch of glass. Stuff I've picked up while rock hounding. Some is "old" glass, which I understand has the potential to be "gassier". I opened the barrel after 48 hours to check progress. Volume was down a little so I topped it off and sealed it back up. Day 7, the barrel had a slight bulge, upon opening I found a robust foam which was holding a lot of grit particles. Checked a few pieces of the glass and found that there was little to no shaping/grinding happening. Took out a little water and added borax, checked the barrel today (day 4) and there's no bulge and it sounds "right". Sunday I'll open and see.
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tkvancil
fully equipped rock polisher
Member since September 2011
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Post by tkvancil on Jan 23, 2014 12:23:40 GMT -5
As far as I know the gas in tumblers is Acetylene from the decomposition of Silicon Carbide. Carbide which was used to generate acetylene gas for lighting many moons ago is Calcium Carbide. Its a long time since I did chemistry, and who knows what chemicals are being cooked up in the sludge in a tumbler barrel but Calcium Carbide could easily be a product in there, even if only momentarily. My Dad had a couple of those calcium carbide lamps. Metal "cans" with a reflector screwed on top ... you'd put in calcium carbide and water then light the resulting gas at the orifice. I always thought they were way cool. I didn't remember the carbide component until your post. Our tap water here has some calcium in it so it certainly could be a contributor.
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Post by pauls on Jan 23, 2014 19:14:15 GMT -5
My maternal Grandmothers first husband killed himself looking for a leak in an acetylene generator, how do you find a gas leak in a dark shed? Light a match of course. This was after he had seriously injured himself smoking while placing charges in a mine, mining was too dangerous so he became a freelance handyman.
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jamesp
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Member since October 2012
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Post by jamesp on Jan 26, 2014 7:11:12 GMT -5
I've had problems with obsidian and glass. Who would guess. I think the problem is tiny bubbles of compressed gasses in the glass/glass-like stones. Try warming the stones, grit, barrel and water before loading the barrel. Put the lid on and let the warm ingredients warm the air in the barrel for a few minutes. Then seal the barrel and let it cool. The cooling air in the barrel should create a slight vacuum actually causing the bottom of the barrel to pull in a little. It can lead to a little faster wear on the bottom of the barrel, but it allows for expansion of the barrel from released gasses. I had a top pop off a 12 lb barrel one time. I definitely don't want that mess again. Normally I do use hot water, as hot as the tap will run. I also let the rocks sit in the hot water for a while in a separate container before putting them in the barrel. Don't remember why but did not do so in this 220 run. When this batch went to 600 I used hot water and a tablespoon of borax in a 3# barrel and got no gas build up. Pics of the finished rocks are now in the Totally Rock Tumbling Photos section (Mix Rough with "Hamrock"). I should stick to using hot water , it's a good tip. Almost two weeks week ago I started a batch of glass. Stuff I've picked up while rock hounding. Some is "old" glass, which I understand has the potential to be "gassier". I opened the barrel after 48 hours to check progress. Volume was down a little so I topped it off and sealed it back up. Day 7, the barrel had a slight bulge, upon opening I found a robust foam which was holding a lot of grit particles. Checked a few pieces of the glass and found that there was little to no shaping/grinding happening. Took out a little water and added borax, checked the barrel today (day 4) and there's no bulge and it sounds "right". Sunday I'll open and see. I reduced the water tk. If the rocks stand 12 inches deep in the barrel i just put a little over 6 inches of water in. I think the rocks rolling into high water makes bubbles. If the water 'table' is lower then you way reduce the splashing. If you took it to the extreme-no water=no bubbles. Of course you would have grit concrete, but it seems the less water the less bubbles. And it seems the SiC gets to work quicker due to more friction. I may add a little water during the coarse grind since mud production is at the max. I like the dryer paste consistency. This method is working very well. There is no way i can run glass w/out this technique. The bubbles are always a grey metallic color. And exude odor. And like you mentioned, with bubbles the grinding practically comes to a halt.
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Tom
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My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
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Post by Tom on Jan 26, 2014 9:46:25 GMT -5
Interesting thread.
I think that water pH could definately cause some gas, has anyone that gets gas tried DI or distilled water? Could it also be altitude? I never get much gas in my QT66, infact its the opposite. The rubber lid liner is pushed out into a bubble on the inside most times and I just need to crack that seal and let air in or out. So some gas but very little.
Lots of reactions going on inside that little rolling barrel, type of rocks, grit breakdown, water chemistry, temp, alltitude, way to much for my wee brain to comprehend. Glad you caught that on time.
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