Eric The Viking
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- 19 Jan 2010
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mr grimsdale":x5d368a2 said:A2 is problematic and best avoided.Chems":x5d368a2 said:Just briefly whats the Pros and Cons of O2 vs A2?
I read recently that people used to tell which was which by the colour of the grinding sparks, but frustratingly the article never said what to look for!
I've been working on my edge tools recently (after years of neglect). I have a 1980s Stanley #5 and a war finish Record #4. I get yellow/red sparks from the Stanley blade on the grinder, and whiter ones from the old Record iron (which isn't itself in very good nick - not my fault, that one!). I also noticed an orange-red glow from a Ward chisel yesterday, when re-hardening (or trying to!). It was absent from my 1970s-80s Marples ones.
Are any of these indicators? The glow ought to tell me what 'impurities' are in the steel (it also had whiter sparks on the grinder), but I'm not sure what it means - it definitely wasn't sodium yellow, much redder than that.
Can anyone shed light on this, or was I too unobservant to get enough data?