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Post by Mel on Sept 15, 2023 17:32:29 GMT -5
I have a polishing wheel made from cast aluminum that has some ancient dried out rubber or foam (?) on it, except the rubber is about the consistency of rock and really uneven. I tried scraping it and was not very successful. Now I'm thinking I need to soak it......in something. Any suggestions on what to try? Or should I just leave it alone, put another pad on top and call it good?
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gunsil
spending too much on rocks
Member since January 2023
Posts: 325
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Post by gunsil on Sept 15, 2023 17:47:12 GMT -5
I'd try soaking it in acetone and see if it scrapes right off.
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,623
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Post by QuailRiver on Sept 15, 2023 21:48:40 GMT -5
Many times I've soak these in lacquer thinner overnight in a Rubbermaid polypropylene plastic food container with a lid. The next day I scrape off any remaining residue with putty knife and then clean up the aluminum disc with fresh lacquer thinner and steel wool. If you choose to do this be sure to follow all of the safety precautions on the lacquer thinner label. Lacquer thinner is a stronger solvent than acetone and Neoprene gloves are recommended when handling lacquer thinner.
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Post by vegasjames on Sept 15, 2023 22:38:40 GMT -5
What about heating it up with a heat gun? Many glues soften up with heat.
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Post by Rockoonz on Sept 15, 2023 23:18:34 GMT -5
Definitely a paint thinner or MEK to remove it, but use nitrile gloves to handle it. If you own a respirator wear it and work in a well ventilated area. Heat may loosen it, but most likely it was attached with a contact cement that's rubber based and will crystallize rock hard with heat. Try to keep the goopy solvent out of the threaded hole.
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gunsil
spending too much on rocks
Member since January 2023
Posts: 325
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Post by gunsil on Sept 16, 2023 11:05:08 GMT -5
Many times I've soak these in lacquer thinner overnight in a Rubbermaid polypropylene plastic food container with a lid. The next day I scrape off any remaining residue with putty knife and then clean up the aluminum disc with fresh lacquer thinner and steel wool. If you choose to do this be sure to follow all of the safety precautions on the lacquer thinner label. Lacquer thinner is a stronger solvent than acetone and Neoprene gloves are recommended when handling lacquer thinner. Lacquer thinner is not stronger than acetone, they are just different. I have tried lacquer thinner on some adhesives and it didn't loosen the adhesive at all but acetone worked like a champ. Rockoonz, man, that MEK is nasty stuff and super carcinogenic but it works well in some instances. I try to avoid it as much as possible.
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Post by Rockoonz on Sept 16, 2023 18:59:48 GMT -5
gunsil acetone is the best for cyanoacrylates but not for PSA and contact cements. I used to use acetone for prepping slabs for dops and intarsia, but the super low flash point and being in AZ caused me to switch to isopropyl alcohol. Any solvent is bad for you, and a fireball is about the worst.
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,623
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Post by QuailRiver on Sept 16, 2023 20:06:32 GMT -5
...Lacquer thinner is a stronger solvent than acetone and Neoprene gloves are recommended when handling lacquer thinner. Lacquer thinner is not stronger than acetone, they are just different. I have tried lacquer thinner on some adhesives and it didn't loosen the adhesive at all but acetone worked like a champ. Rockoonz, man, that MEK is nasty stuff and super carcinogenic but it works well in some instances. I try to avoid it as much as possible. Perhaps I could have worded it better, but lacquer thinner is a stronger solvent than acetone in the context of Health Hazard. Acetone has a Health hazard rating of 1 while blends of lacquer thinners usually have a health hazard rating of 2 or even 3. Hence the recommendation to wear neoprene gloves which are usually impervious to ingredients in lacquer thinner blends.
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Post by Mel on Sept 17, 2023 0:40:08 GMT -5
Here’s hoping some acetone will work since I have it on hand. I suspect it was put on with lapidary cement (found a tube in the same box) but obviously no way of being certain.
Fingers crossed!
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Post by Rockoonz on Sept 17, 2023 1:25:03 GMT -5
Give it some time to soak in and you will be good. Be sure your container is airtight and open it outside away from sparks, flashpoint is MINUS 4 degrees F and a 2.5% concentration in the atmosphere is enough to ignite from a spark. If you can make a lot of cuts in the foam to allow it to soak in faster it may help, did a lot of stripping old rubber from inserts in my early days in the rubber mill, recoated the inside of ballast valves for submarines by hand for awhile, some were like 24" diameter.
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Post by liveoak on Sept 17, 2023 6:15:39 GMT -5
I did one the other day with the heat gun - slowly. Mine wasn't as old & crusty but it worked fine.
Patty
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Post by Mel on Sept 17, 2023 12:05:50 GMT -5
Give it some time to soak in and you will be good. Be sure your container is airtight and open it outside away from sparks, flashpoint is MINUS 4 degrees F and a 2.5% concentration in the atmosphere is enough to ignite from a spark. If you can make a lot of cuts in the foam to allow it to soak in faster it may help, did a lot of stripping old rubber from inserts in my early days in the rubber mill, recoated the inside of ballast valves for submarines by hand for awhile, some were like 24" diameter. Lee, you have got to be one of the most interesting people I know. You have so much knowledge! Edit: acetone took it right off after soaking overnight. I will definitely be using a disposable container next time. The black sludge from the melted foam & acetone was like tar, but the head is clean and good for a new pad.
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