Serious question, why does everyone quench hot steel in oil like it's the only way?

Three years ago at a shop in Tucson, an old timer showed me he quenches simple carbon steel in room temp water and it gets just as hard for half the smoke. Has anyone else experimented with different quenchants on basic projects?

3 comments

3 Comments

river3201mo ago

Does that old timer's water leave that weird rust patina you get with oil?

jana_scott1mo ago

@river320 that's a good question... does the water look more orange or brown when it sits? I've noticed some well water leaves this weird yellow tint on everything, and usually it's the iron content that causes it. Hard to tell if it's the same kind of staining unless you let a glass sit out for a few hours.

carter.gavin1mo ago

That glass test is the real tell. Jana is spot on about letting it sit for a few hours because the color change happens gradually. Iron rich well water usually turns a brownish orange after it sits, not a bright orange like you'd see with something like an oil leak or chemical runoff. The old timer's water sounds more like what you get when there's heavy iron bacteria in the lines, which leaves that gritty rust colored film on everything from the toilet bowl to the shower curtain. Oil contamination tends to leave a rainbow sheen on top of the water, not a patina or stain that settles on surfaces. So if it's leaving that rusty buildup on the fixtures and it's not showing any oily slick, it's almost certainly the iron content from the ground water. That kind of staining is a pain to clean off too once it bakes onto porcelain.