sisyphus
off to a rocking start
Member since March 2020
Posts: 14
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Post by sisyphus on Mar 23, 2020 11:39:59 GMT -5
Okay, three times in the last ten days this noobie has experienced pressure build up and leakage in a three lb Thumler barrel twice, and a three lb Lortone once. Each time it has been with medium grit. Twice with amethyst and rose quartz, and once with garnets. I don't think that is relevant but I included the info. The grit is National Geographic. it has happened with poly beads and with ceramic. My first thought was that it was a change in the ambient air pressure. If it was sealed on a high pressure day and a low moved in, then... maybe? Heat building up as the stones wear down and the slurry gets thicker? Barrels that just don't fit/seal tightly?
The Lortone barrel, when caught, had a very prominent bulge at the bottom, a loose nut and washer. The Thumler was caught early each time, as I noticed a pitch change in sound from the other room. The Lortone was found at 6Am as I awoke for a nature call. I am not confident while they run when I sleep now. When I can I will get a large aluminum baking pan to set them in as an containment.
If there is a fix, or something I can do to prevent this please reply, thanks all. Stay safe.
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Post by RocksInNJ on Mar 23, 2020 12:53:14 GMT -5
Temperature change can also affect the pressure build up as well. During winter and because my tumblers are on a screened in outdoor porch I use hot water in the barrels with some rock salt to prevent freezing. I’ve heard of people also using different things like borax, Tums, baking soda and other things to prevent the build up, but I haven’t tried any of them. I haven’t had a blowout since I’ve stopped using the kitty littler.
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Post by aDave on Mar 23, 2020 13:10:00 GMT -5
Okay, three times in the last ten days this noobie has experienced pressure build up and leakage in a three lb Thumler barrel twice, and a three lb Lortone once. Each time it has been with medium grit. Twice with amethyst and rose quartz, and once with garnets. I don't think that is relevant but I included the info. The grit is National Geographic. it has happened with poly beads and with ceramic. My first thought was that it was a change in the ambient air pressure. If it was sealed on a high pressure day and a low moved in, then... maybe? Heat building up as the stones wear down and the slurry gets thicker? Barrels that just don't fit/seal tightly?
The Lortone barrel, when caught, had a very prominent bulge at the bottom, a loose nut and washer. The Thumler was caught early each time, as I noticed a pitch change in sound from the other room. The Lortone was found at 6Am as I awoke for a nature call. I am not confident while they run when I sleep now. When I can I will get a large aluminum baking pan to set them in as an containment.
If there is a fix, or something I can do to prevent this please reply, thanks all. Stay safe.
Don't know if I have a great answer for you, but the Thumler 3A barrels have been known to be quite finicky when it comes to sealing, and they can be prone to leak. Apparently it has something to do with the way the lid seals up. www.google.com/search?q=thumler+3a+leak&sitesearch=forum.rocktumblinghobby.comAs far as the Lortone findings, I'm a bit surprised with your pressure buildup in your second stage. My general sense is that most folks have problems in the initial stage, but it clearly happened for you, especially with the bulge being noted. Some material is more prone than others for causing a pressure buildup, so it's just something you may have to check if you keep running that stuff. Perhaps a "burp" of the barrel by opening the lid every couple/few days may be helpful.
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oldschoolrocker
fully equipped rock polisher
Member since January 2019
Posts: 1,540
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Post by oldschoolrocker on Mar 23, 2020 13:20:23 GMT -5
Havent had this issue myself but have read about it frequently. Mainly with tumbling obsidian or other glass but also with rocks with metallic content like hematite. Also read possible cause bein the ph of the water. Most all solutions offered were to use hot water, baking soda, sugar to counteract gas buildup. May try one in one barrel, one in another and note what works or doesnt.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Mar 23, 2020 13:40:50 GMT -5
Is there anything else being added to the barrel? Like prior slurry, weird organic matter, etc?
Sealing them when hot should create a "negative" pressure in the barrel as it cools.
Careful with the baking soda or other carbonates, you'd want those to be dissolved and react first before sealing the barrel.
Sometimes in my coarse grinds the first day will build pressure, but not a lot, and the barrel bottom only slightly bulges. Then subsequent days, even without venting, the pressure drops and the bottoms cave inwards slightly.
How tight are you tightening these up? I probably over tighten mine, but I also don't have any blowouts at the slightest sign of increased pressure anymore. If they go boom now, I'll hear it!
Also, yes, catch pan underneath is pretty much standard equipment for my setup. It's a lot easier to clean by moving it outside than cleaning off whatever surface (or carpet) it's on.
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Post by joshuamcduffie on Mar 23, 2020 13:46:16 GMT -5
I haven't had any blowouts but I have had an issue with leakage. It occurred when I was reloading with the same grit and therefore wasn't as good as usual about cleaning the rim of the barrel. That would not explain your issue, though.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,666
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Post by Fossilman on Mar 23, 2020 15:47:17 GMT -5
I burp my barrels... You can tell if they will blow by the pressure on the bottom of the barrels.. What a mess they make and the smell is terrible...LOL
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sisyphus
off to a rocking start
Member since March 2020
Posts: 14
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Post by sisyphus on Mar 24, 2020 10:18:13 GMT -5
Is there anything else being added to the barrel? Like prior slurry, weird organic matter, etc? Sealing them when hot should create a "negative" pressure in the barrel as it cools. Careful with the baking soda or other carbonates, you'd want those to be dissolved and react first before sealing the barrel. Sometimes in my coarse grinds the first day will build pressure, but not a lot, and the barrel bottom only slightly bulges. Then subsequent days, even without venting, the pressure drops and the bottoms cave inwards slightly. How tight are you tightening these up? I probably over tighten mine, but I also don't have any blowouts at the slightest sign of increased pressure anymore. If they go boom now, I'll hear it! Also, yes, catch pan underneath is pretty much standard equipment for my setup. It's a lot easier to clean by moving it outside than cleaning off whatever surface (or carpet) it's on. No, nothing extra added, just the ceramic this time. I will try the hot water. Baking soda? Am unsure of it's abrasive grade. Tightness of the Thumler barrels is predetermined by the manufactured tolerances built into the three parts. (see next post)
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sisyphus
off to a rocking start
Member since March 2020
Posts: 14
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Post by sisyphus on Mar 24, 2020 10:30:43 GMT -5
Last night, just before bed, I checked on it again. The lid was just breaking out of it's confines. I set it aside bottom down, and went to bed. I resolved to check all the dimensions comparatively to my other Thumler barrels. What I found was a band that was noticeably larger in diameter than the others. I swapped it out, and it is running with the fresh band. I can't make a definitive conclusion yet. The larger band may just have had a 'set' in it from being on the barrel. I will give it a day to relax and recheck. I may rig up a comparison test to measure it's stretch under tension using my trigger pull gauge (I work on my own rifles, it's Michigan after all.) I can say this... that band was much easier to install than the others. Hint hint.
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Post by broseph82 on Mar 24, 2020 13:47:36 GMT -5
I had my 12lb Lortone bust open over night. Not even a full 24hrs into my 46/70 grind with slag glass and saw where it had leaked all over garage. Barrel is warped like crazy too. Ugh will try again with a good amount of borax and see. Hopefully that cuts down on it
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sisyphus
off to a rocking start
Member since March 2020
Posts: 14
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Post by sisyphus on Mar 24, 2020 13:56:25 GMT -5
Cleaned it up, ran it about 3 hours, happened again. I washed the rocks. After only 3-1/2 days they looked OK to pre-polish (mostly). I scrubbed them good with dish soap and an old toothbrush. I put them in a different barre, I have one for each stage. l with poly-beads. It's only about half full this time, maybe 5/8's was too much. They just went into pre-polish 5 minutes ago. Let's see.
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Post by broseph82 on Mar 24, 2020 14:16:07 GMT -5
Cleaned it up, ran it about 3 hours, happened again. I washed the rocks. After only 3-1/2 days they looked OK to pre-polish (mostly). I scrubbed them good with dish soap and an old toothbrush. I put them in a different barre, I have one for each stage. l with poly-beads. It's only about half full this time, maybe 5/8's was too much. They just went into pre-polish 5 minutes ago. Let's see. That’s crazy. Try using distilled water instead of tap
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Post by broseph82 on Mar 25, 2020 10:10:29 GMT -5
imgur.com/gallery/qtuOW7iThis was after opening it. The rubber gasket was stuck to the metal top when I lifted to top off. New gasket on the way. I think the barrel was maybe running for 12-15hrs before it blew. Had mostly factory slag glass and one piece of obsidian with a cup of 46/70.
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JBe
starting to spend too much on rocks
Member since January 2019
Posts: 103
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Post by JBe on Mar 25, 2020 10:31:13 GMT -5
The differences in lid design are one of the reasons I returned the Thumler I started with and went with Lortone. The Lortone lids are more secure. I've had barrels swell quite a bit but haven't had any blowouts yet. I keep my rotaries in large aluminum cookie sheets to contain any leakage. I also fill my barrels with hot water assuming the thermal contraction as the barrel cools to ambient temperature buys me a little more margin. I don't know if this ultimately makes much of a difference though. It's interesting you have this happening with medium grit and not the rough stage. It seems unlikely but it could possibly be contaminated grit. If you can buy more grit from another source and try it with the same rocks. That should tell you if it's the grit or not. If you're going to keep tumbling you'll need more grit eventually anyways. Edit- punctuation
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sisyphus
off to a rocking start
Member since March 2020
Posts: 14
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Post by sisyphus on Mar 25, 2020 10:44:27 GMT -5
The barrel with the pre-polish in it exhibits no signs of expansion after almost 20 hours. Only 3-1/2 days of 2nd stage grit? That is what worries me now. I'm a noob, so my judgement is not based on experience but I culled the obvious ones out those inside looked ready based on my previous run of stuff I picked up from out behind the house. (One was a small, but very pretty triangle of unakite.) I might have to take the plunge and get one of those $$$ upright wet vibratory units (forgot the name) At my age and decrepitude I need a simpler hobby than restoring old motorcycles. Maybe all the parts comprising that barrel unit are at the low end of allowable tolerances, when stacked together, it's a lemon, just like a car.
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sisyphus
off to a rocking start
Member since March 2020
Posts: 14
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Post by sisyphus on Mar 25, 2020 10:52:13 GMT -5
The differences in lid design are one of the reasons I returned the Thumler I started with and went with Lortone. The Lortone lids are more secure. I've had barrels swell quite a bit but haven't had any blowouts yet. I keep my rotaries in large aluminum cookie sheets to contain any leakage. I also fill my barrels with hot water assuming the thermal contraction as the barrel cools to ambient temperature buys me a little more margin. I don't know if this ultimately makes much of a difference though. It's interesting you have this happening with medium grit and not the rough stage. It seems unlikely but it could possibly be contaminated grit. If you can buy more grit from another source and try it with the same rocks that should tell you if it's the grit or not. If you're going to keep tumbling you'll need more grit eventually anyways. Come to think of it, the grit was from the tumbler kit, the factory supplied stuff. This batch is the National Geographic stuff from Amazon. I got the tumbler at a yard sale and the grit pack was with it so I assume it's from Thumler.
Another thought is the chemistry, I'd have to do some digging, but, silicon carbide if separated into constituents mixed with water could be carbide in water. I think that makes acetylene gas?
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sisyphus
off to a rocking start
Member since March 2020
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Post by sisyphus on Mar 25, 2020 11:00:00 GMT -5
Nope, not this reaction. It takes calcium carbide and water. A good thing I guess.
There did seem to be an exothermic reaction going on inside, just based on the warmth of the barrel itself. Fearsome confused here.
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Post by knave on Mar 25, 2020 12:20:10 GMT -5
Nope, not this reaction. It takes calcium carbide and water. A good thing I guess.
There did seem to be an exothermic reaction going on inside, just based on the warmth of the barrel itself. Fearsome confused here.
The friction of the rocks and the shaft-to-barrel does produce a noticeable amount of heat.
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sisyphus
off to a rocking start
Member since March 2020
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Post by sisyphus on Mar 25, 2020 21:15:55 GMT -5
Pre-polish still running with no signs of blowout. I am measuring from the rim to the cover regularly with a caliper. Seems to be static, no movement. Yet I notice that a fine line of dry powdery grit is at the groove line. How does that get there? Still I will take it off the tumbler while I sleep, make up the time later.
Think I will try your hot water suggestion JBe, next time. Makes sense.
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EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
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Post by EricD on Mar 26, 2020 17:30:16 GMT -5
I have a lot of pressure buildup running glass, but only in coarse which is all my rotary does.
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