How much draft does the chimney part of the chimnea create? I too am surprised that something the bulk of a blade would reach 800+degC unless there is some air being drawn through. Makes me curious though. I have a platinum thermocouple for my forge and am tempted to try it in a wood fire the next time I have a chance.
We all tend to use O1 here in the UK because it is so easy to get, and many other simpler steels are not so available. O1 is pretty forgiving, but as far as proper heat treating goes, it is actually a more complex steel, a "tool steel" not just a "carbon steel". As such, it will not get fully hard by simply taking it to non-magnetic (hate the term cherry red, nothing that was what I think is cherry red was ever non-magnetic or ready to quench) and quenching. That will work for 1084 and similar steels, but O1 is meant to be soaked at a consistent, controlled temperature for 10-15 minutes to fully dissolve the carbon which in the annealed state is tied up with the more complex alloying elements.
First time I read that, I didn't want to believe it, after all, I was getting hardness, I thought, files skated and I could temper at 170degC and get something that would cut and the edge would not deform too much against a brass rod. However, when fully hard, O1 needs a higher temperature to temper it. That I was tempering at 170 meant that I was not getting full hardness. There was LOTS of stuff on the internet forums where other makers were heat treating with torches or forges and all getting similar results, sort of a collective self reinforcing shared opinion. We all made knives that worked, but we don't get the full performance of the steel that way. There is something to be said for trying to get a simpler steel that will heat treat correctly with the simple tools and heat sources available to the beginner.
Multiple quench cycles do help with getting more carbon into solution with O1. Not ideal and a bit of a bodge dodge, but better than simply getting hot once and quenching once.
We all tend to use O1 here in the UK because it is so easy to get, and many other simpler steels are not so available. O1 is pretty forgiving, but as far as proper heat treating goes, it is actually a more complex steel, a "tool steel" not just a "carbon steel". As such, it will not get fully hard by simply taking it to non-magnetic (hate the term cherry red, nothing that was what I think is cherry red was ever non-magnetic or ready to quench) and quenching. That will work for 1084 and similar steels, but O1 is meant to be soaked at a consistent, controlled temperature for 10-15 minutes to fully dissolve the carbon which in the annealed state is tied up with the more complex alloying elements.
First time I read that, I didn't want to believe it, after all, I was getting hardness, I thought, files skated and I could temper at 170degC and get something that would cut and the edge would not deform too much against a brass rod. However, when fully hard, O1 needs a higher temperature to temper it. That I was tempering at 170 meant that I was not getting full hardness. There was LOTS of stuff on the internet forums where other makers were heat treating with torches or forges and all getting similar results, sort of a collective self reinforcing shared opinion. We all made knives that worked, but we don't get the full performance of the steel that way. There is something to be said for trying to get a simpler steel that will heat treat correctly with the simple tools and heat sources available to the beginner.
Multiple quench cycles do help with getting more carbon into solution with O1. Not ideal and a bit of a bodge dodge, but better than simply getting hot once and quenching once.
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