jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Jan 26, 2014 10:58:19 GMT -5
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Jan 27, 2014 12:33:30 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. I have also noticed this about the QT66. I've got some stromatolite running now. First time I put that material in a 3# barrel it caused problems and there was only a couple pieces. Makes me wonder if barrel size makes a difference some how. I'm having and haven't had gas issues in the 6# barrels.
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Post by Starguy on Jan 28, 2014 19:29:05 GMT -5
I hate it when I have gas issues. The wife's not too keen on it either.
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Post by Toad on Jan 28, 2014 23:47:46 GMT -5
Never had a problem with gassing. I use tap water and borax. Never reuse grit. I have always used 12 lb. barrels. Don't know if the bigger volume helps???
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Post by Toad on Jan 28, 2014 23:55:23 GMT -5
The friction of tumbling also builds up heat, so something else I do is fill the barrel with hot water. That way the mix actually cools down as the tumbling starts. And even when the slurry builds heat over the coarse of the following week, it will never get as hot as the water I put in it to start the cycle.
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Post by Starguy on Feb 3, 2014 22:04:47 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. There's a big difference between silicon carbide and calcium carbide. Acetylene gas isn't an issue with silicon carbide. It's pretty inert as far as gas forming goes. The biggest problem with gas forming is compressed air in the stones. It gets released as the bubbles are exposed by tumbling. Glass and obsidian are the biggest culprits. Neither have a crystalline structure, and are considered a viscous fluid. They tend to have bubbles inside that have air pressure higher than normal atmospheric pressure so when the bubbles are exposed it releases a little bit of gas. If you try using hot water to charge the tumbler, it should fix the problem.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Feb 4, 2014 3:48:26 GMT -5
Never had a problem with gassing. I use tap water and borax. Never reuse grit. I have always used 12 lb. barrels. Don't know if the bigger volume helps??? Reusing grit has caused problems for me too. And tumbling glass and obsidian is a challenge due to what starguy mentioned. Reducing the amount of water has been my solution for all stones other than glass and obsidian. But helps a lot w/those too.
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RockyBeach
starting to spend too much on rocks
Member since July 2023
Posts: 240
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Post by RockyBeach on Jul 11, 2023 19:23:38 GMT -5
Bumping this old thread because it relates to some new questions (mine) and reading it might help some others also new to the hobby.
The advise about the hot water and Borax sounds quite appealing and will be tried with the next batch of rocks !
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