"red heat" depends on the lighting right? ;)
500C is about 932F.
In the dark, stuff starts glowing at ~750F.
What I want to know is what the real "starts to glow in the dark"
Seems like I read where it's really 752F (400C) or was the 752F
figure a conversion from the rounded off 400C? :/
Alvin in AZ
When working Noble Metals I always figured dull red with my bench light
off off to be about 1200F then quench in water/acid. Makes them very nice
to work. I anneal 0-1 by heating to about 1500F then slow cooling.
I messed around for about a year trying to figure out a way to draw
the temper on O1 and 1095 to make springs without buying a special
furnace or doing it "blacksmith style". Tried blacksmith style and
didn't work out so good for me. :/ Needed more time at-temperature
and a way to keep from over-heating it both.
Then I figured it out... remembered a fact from my reading... at
~750F "stuff" starts to glow in the dark. :) That's a bench mark
a guy could work from. :)
I put the fresh quenched "springs" in boiling water to clean them.
Then turned out all the lights except the light over the stove.
Lay the pocket knife "springs" on the electric burner and turn it
on, and at the same time turn out the light. Pitch black, can't see
nothin'. :) As soon as I can see the electric stove coil... quick
and turn it off and turn on the light and watch the colors run. :)
After a light sanding of the parts, I would draw them again.
That's the "old" way. ;)
My target temperature is 650F.
It seems to work better to find the adjustment for the stove where
it turns itself off just as it glows at any spot in the coil, and
lay the spring blanks on there for 10 minutes.
That adjustment can be found with the lights off etc and what's cool
is it won't over heat the springs and can keep them hot long enough
to work even for that dangged ol' slow O1 to turn into a spring. ;)
Alvin in AZ
ps- to heat treat I let the steel's arrest-point tell me when to
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