What color should i be looking for while heating CRA 1095? I will be using refractory bricks as a kiln, with a benzomatic torch using MAPP gas, or should i use propane? Will MAPP gas be a little to hot? Am i suppose to hold at (1500 F) for 10 minutes then quench in a fast cooling medium? I was going to use Chevron Texaco 70 quench oil, is this a good quenching oil. Should i do the magnet test when i reach a certain color then put it back in for whatever time i have left from the 10 minutes or do i reach the color or temp i need and then hold for 10 minutes?
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What color should i be looking for heating 1095?
- Thread starter SethO
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- Dec 21, 2006
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This should probably be moved over to Shop Talk.
Use MAPP over propane. Sure, you can overheat the blade with MAPP or Propane. Hold at 1475°F for 10 minutes and quench in the fastest oil you can find. Texaco 70 is around an 11 second oil I believe and is too slow for 1095. It will work with very thin 1095 cross sections, but only thin cross sections. I would use canola oil warmed to 130°F over that oil anyday. 1095 requires such a fast quench, brine is often used, so the Texaco 70 isn't the best option. Canola/peanut warmed to 130°F approaches the speed of a fast oil like P50.
Don't go buy color. Use the magnet. Here is the trick....magnet will stop sticking at around 1414°F. But you still need to be hotter.......like around 60°F or 70°F hotter. So simply notice what shade of red/orange you are at when the magnet stops sticking at 1414°F and then go "a shade or two hotter".....then try to hold that for 10 minutes.....then quench.
The magnet works very well...but so does judging heat by decalescence. You'll notice that as you are heating the blade towards the critical temperature around 1475°F that a "shadow" will move across the blade. This tells you, once the shadow is gone and starts to turn red/orange again that you have reached the steel's critical temp. Try to soak 10 minutes there. Decalescence being more accurate than the magnet.
Use MAPP over propane. Sure, you can overheat the blade with MAPP or Propane. Hold at 1475°F for 10 minutes and quench in the fastest oil you can find. Texaco 70 is around an 11 second oil I believe and is too slow for 1095. It will work with very thin 1095 cross sections, but only thin cross sections. I would use canola oil warmed to 130°F over that oil anyday. 1095 requires such a fast quench, brine is often used, so the Texaco 70 isn't the best option. Canola/peanut warmed to 130°F approaches the speed of a fast oil like P50.
Don't go buy color. Use the magnet. Here is the trick....magnet will stop sticking at around 1414°F. But you still need to be hotter.......like around 60°F or 70°F hotter. So simply notice what shade of red/orange you are at when the magnet stops sticking at 1414°F and then go "a shade or two hotter".....then try to hold that for 10 minutes.....then quench.
The magnet works very well...but so does judging heat by decalescence. You'll notice that as you are heating the blade towards the critical temperature around 1475°F that a "shadow" will move across the blade. This tells you, once the shadow is gone and starts to turn red/orange again that you have reached the steel's critical temp. Try to soak 10 minutes there. Decalescence being more accurate than the magnet.
Alright thanks a lot, i will use the canola oil, magnet and shadow methods. I have one more question when i reach that 1475 degrees F and notice it's getting to hot should i turn the gas down some or pull the blade out for a second? This is only part am not sure what to do. Since i can't control the temperature, do i just do the best i can do with the makeshift kiln/oven?
- Joined
- Dec 21, 2006
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If you notice the blade getting too hot (especially the thinner areas like the tip), cycle the blade in and out. You should try to have the heat regulated to produce only enough heat to reach 1500°F or so, but it is hard to do that and thin sections warm up fast anyway. So best to just cycle it in and out of your heat, just like a Japanese blade smith!
- Joined
- Jan 28, 2011
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- 393
One more thing, the color is much easier to judge if it's dark or almost dark while you're working.