Home heat treating setup help

slashfuzzle

slashfuzzle

Joined
Mar 16, 2018
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Hey guys,

I'm looking to do some heat treating at home on some blades made with simple high carbon steels like 1084/15N20. I'm just learning the process, but am looking for recommendations on a simple home setup that will handle this well without costing me $1k+ for a heat treat oven. I've seen the brick mini forge/torch setups, but looking for maybe the next step up.

Would something like the Atlas Mini Forge be a good starter? Or maybe something like this forge?

I'm not planning to forge my knives as I do stock reduction, so just need a simple setup for heat treating the steel properly.

Any suggestions?

Thanks!
 
The Atlas mini works very well for what you're talking about doing, and if you did ever decide to forge it's great for smaller projects.
 
A forge big enough to fit a pipe muffle is a good idea. The pipe muffle is a more thermally stable sub-compartment within the forge. If you seal the ends of the muffle (soft fire brick round cutouts), insulate it 180-270 degrees around the pipe surface with some kaowool, and add a K-type thermocouple, you can have a pretty good heat treating oven for simple steels. Make a shelf inside the pipe out of soft firebrick, too. I did all of this before purchasing an oven. You have to mother hen your forge settings to keep your target temperature stable, though.
 
I have used an Atlas Mini for demo and teaching many times. It does HT fine for smaller blades in simple steels.

Keep the blade moving and turning to heat evenly. Stick the point in the corners as it gets to non-magnetic to avoid overheating the tip.
 
Awesome, thanks for the help guys!

MBB said:
You have to mother hen your forge settings to keep your target temperature stable, though.
Click to expand...

Yeah I was wondering about that. How would you monitor temp in something like the Atlas Mini? Or do you just check with a magnet and adjust visually from there?
 
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You can't really monitor the temperature, because a venturi forge is going to run hotter than 1500F. All you can do is turn the propane pressure down to where is still runs stable and go from there.
You just keep the blade moving, watch it to get an even red, check on the magnet, and when a bit past non-magnetic ... quench in a gallon of 120F canola oil.
 
Stacy E. Apelt - Bladesmith said:
You can't really monitor the temperature, because a venturi forge is going to run hotter than 1500F. All you can do is turn the propane pressure down to where is still runs stable and go from there.
You just keep the blade moving, watch it to get an even red, check on the magnet, and when a bit past non-magnetic ... quench in a gallon of 120F canola oil.
Click to expand...

Got it, makes sense. Any particular magnet you recommend to test with?
 
I just used a telescoping magnet from the parts store when I did things like that. Allows you to get at the blade without pulling it out and away from the forge a whole bunch and keeps your hand away from the hot blade/dragons breath.
 
slashfuzzle said:
Yeah I was wondering about that. How would you monitor temp in something like the Atlas Mini? Or do you just check with a magnet and adjust visually from there?
Click to expand...

If you use a muffle, you fiddle with the gas flow rate based on your thermocouple temperature reading, trying to keep it within range. For simple 10XX steels, this doesn't make a lot of sense. Just use the methods discussed above. I was overachieving and trying slightly more complex steels like O1, which require a longer soak at temperature.
 
I have a square welding magnet struck on the side of the forge. I pull out the blade and touch it to the magnet to see if it still is attracted. When it stops, that is around 1425F. Heat about 50-75° hotter and you are right at the quench temperature. I look at the shade of red when it stops sticking to the magnet and heat just a little brighter/lighter red color , then quench.
 
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