Note on quenching oils after a trip to a forge demo in Ohio

Honestly, I went to a blacksmithing demo last weekend at a small farm in Ohio, and the guy running it talked about how his quenching oil went bad after just 3 months. He said he didn't filter it regularly and it got all sludgy, which messed up his hardening on a batch of 10 knives. I always just assumed oil lasts forever, but now I'm checking my own bucket every 2 weeks. He recommended running it through a fine mesh strainer after each use, which sounds simple but I never thought to do it. Has anyone else dealt with oil getting too thick or dirty over time?

2 comments

2 Comments

allen.william1mo ago

How often do you really need to worry about quenching oil going bad though? I've had the same bucket of parks 50 for almost 4 years and I never strain it or filter it. I just scoop out the big chunks of scale with a slotted spoon every few months. Got it from a guy who was shutting down his shop and it was already dark and thick when I got it. Still hardens 1095 just fine every time. If you're filtering every 2 weeks you're just wasting time. That demo guy probably had something else wrong with his setup or was overheating the oil way past what it can handle. Sludge builds up but unless you're drowning your steel in forge crud it pretty much works the same.

quinns201mo ago

@allen.william you got lucky with thick oil, but most people won't.