rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jul 2, 2011 3:49:20 GMT -5
Well, after tumbing 24/7 with multiple tumblers for 5 years or so, I never had a problem with gas build-up. Then I shut down my tumblers totally for 2 years, fired one of them back up a short time ago, and was met by this surprise: That came about from tumbing some rough slag glass that I bought last year while on a summer vacation to Oregon. I've seen others talk about glass being gassy, and frankly I was rather skeptical since I've never encountered gassy material before. But I took people's warnings to heart and opened the barrel frequently, but clearly that still wasn't enough to prevent a messy blowout. I'm continuing with the tumble, opening the barrel daily. I really don't understand the chemistry here though... glass is one of the least reactive materials around, heck, you can store incredibly strong acids in glass bottles. So why a glass tumble reacts to release gas is a mystery to me... I wouldn't even believe it to be true, except I've now seen it myself!
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snuffy
Cave Dweller
Member since May 2009
Posts: 4,319
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Post by snuffy on Jul 2, 2011 6:28:47 GMT -5
Yeah,I ran a 12lb batch of obsidian and glass recently.I check for gas buildup by feeling the back end of the barrel.It's normally indented.About the first few days,there was no gas buildup, but about the 4th or 5th day,the end of the barrel swelled out almost an inch.Had to burp it twice a day from then on.
snuffy
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Jul 2, 2011 9:45:08 GMT -5
the gas is not a chemical reaction. It occurs from the microscopic air bubble present (especially in slag glass) burst as you wear down the glass.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Jul 2, 2011 22:43:52 GMT -5
Well, since the ice is broken, I'll fess up to my little mess of two weeks ago. Started a new batch of rough in our 5-gallon barrel unit, beach agate. Thought I'd cut the fat piggie by dumping the slurry from our vibe lap in to use it up, and help the grind get started. After the third day I was about to close the shed door for the night, thought I better look at the machine; glad I did, the ends of the barrel were domed unbelievably. Shut it off and burped the barrel; fhe stuff squirted up and hit the 8+ foot ceiling before I got a hand over it. Let the pressure drop down and left it 'till the next morning. Odd to us, there was no odor. Spent near all day cleaning the mess. After removal, the 12 1/2" dia., 3/4" thick UHMW plastic lid was domed 9/32", normally flat. My only guess as to what happened: a reaction caused by the minute amount of metal picked up in the slurry from the wear on the vibe lap. After a thorough cleaning of everything, barrel, and rocks, I started again w/fresh 80 grit, no more gas. Two positives here, don't do that again [learned something], and my barrel held, didn't leak. Have had some gas fizzes before, but nothing like this. Attachments:
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Post by paulshiroma on Jul 2, 2011 23:30:29 GMT -5
Bummer ... I came home to something similar but it was due to the lid getting a little hole.
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Post by Toad on Jul 3, 2011 7:58:25 GMT -5
Ick, thanks for the warning.
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Post by connrock on Jul 3, 2011 9:34:39 GMT -5
I've found 2 things that cause gas,,,,in a tumbler. A brand new barrel and just about any type of glass including obsidian. On the other hand,,, When I was young it took things like beer and pickled eggs,sauerkraut,imported provolone cheese and a few others to create gas. Now as I get older even a Popsicle will do it! LOL ;D connrock
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