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That old timer told me to quench in used motor oil
Met a guy named Hank at a hammer-in near Pittsburgh who swore by quenching hot steel in used 10W-30. Said it gave a better edge than any fancy brand. Tried it on a kitchen knife last month and the smell alone made my wife ban me from the house for two days. Anyone else get handed terrible advice that sounded too good to be true?
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kevin_west1mo agoMost Upvoted
Used to think Hank was full of it too, honestly. Read a bunch of stuff online about how used oil has all these nasty contaminants and water in it that can mess up the quench. But then I actually tried it myself on a couple of beater knives. Not gonna lie, the smell is bad and you gotta do it outside. But the blades came out hard as hell and took a real nice edge. I ain't saying it's better than a fancy commercial quenchant, but for a shop knife or something you don't care about, it works way better than I thought it would. Changed my whole view on the old school methods after that.
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pat_fisher241mo ago
Hank's probably just trying to get rid of his old oil so he don't have to pay for disposal.
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Yep, I've been down this road before with a neighbor who tried to pull the same thing on me. The thing is, old oil like that is a pain to get rid of legally, and if you don't have a proper disposal setup it costs money at the recycling center. What I did was told him straight up I'd take it off his hands but only if it was still good and not full of junk like metal shavings or water. You gotta test it first, just let it sit in a clear bottle for a day to see if any gunk settles at the bottom. If it's clean and he's just being lazy, then yeah it's a score, but otherwise you're just taking his problem. I'd ask to see the bottle before you commit, that's the real test.
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