Question about seasoning scrapers with torch heat

Always told myself heat was heat and it didn't matter where it came from... but after watching a guy in Cincinnati ruin a brand new scraper by getting it cherry red with a propane torch, I'm starting to think there's a sweet spot most people ignore. What's your method for tempering the edge without going too far?

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3 Comments

alice2693mo ago

Man I feel that pain about the cherry red mistake! I've been there too, watched a buddy turn a nice scraper into a brittle mess because he got impatient with the torch. What works for me is using a small butane pencil torch instead of a big propane one, way easier to control the heat. Keep the flame moving constantly and pull it away the second you see that first hint of yellow on the edge, like Seth Harris (@seth_harris36) said, that light straw color is your target. I actually quench it in water right at that point instead of slow cooling, seems to give me a harder edge that holds up better for scraping. Just make sure the edge is clean and dry before you start or you'll get weird hot spots that mess up the temper.

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graydavis3mo ago

Stopped chasing that cherry red look myself after messing up a good scraper. Now I just hit it with a torch until the edge barely starts to turn that light straw color and then let it cool slow on the bench.

4

seth_harris363mo ago

Ramping up the heat on purpose and letting it slow cool is the way to go honestly... I started doing something similar after I ruined a perfectly good mortise chisel trying to get it glass hard. That light straw color on the edge is all you really need for most work, anything past that and you're just asking for trouble.

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