Soak Time When Heat Treating

Stark Knives

Stark Knives

Joined
Mar 19, 2010
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I have always sent my knives out to be professionally heat treated, but just got a heat treating oven so that I can do some knives on my own. I just have one noob question regarding soak time. At what point do you start timing the soak? For example, if a heat treat recipe calls for a 10 minute soak, would I start timing once the knife is non-magnetic?

Thanks!
 
Soak starts when you hit target temp. Set the oven for 10-20 min longer than your desired soak, or even 30+ min and once the oven it at temp, put the knife in once stabilized. Then, once the oven rebounds from the change in temp, and equalizes, start timing for quench.
 
Stark Knives said:
I have always sent my knives out to be professionally heat treated, but just got a heat treating oven so that I can do some knives on my own. I just have one noob question regarding soak time. At what point do you start timing the soak? For example, if a heat treat recipe calls for a 10 minute soak, would I start timing once the knife is non-magnetic?

Thanks!
Click to expand...
Do you have a digital controlled kiln? I usually put the blades in cold and let it ramp up to temperature. I hold at that temp got the soak time. If the soak time is 10 minutes, I usually set the timer for 13 minutes, which gives me a little time to quench all the blades. I don't usually do more than 5 blades at a time. You shouldn't have to worry about "non-magnetic when you have precise temperature control.
 
J. Hoffman said:
Do you have a digital controlled kiln? I usually put the blades in cold and let it ramp up to temperature. I hold at that temp got the soak time. If the soak time is 10 minutes, I usually set the timer for 13 minutes, which gives me a little time to quench all the blades. I don't usually do more than 5 blades at a time. You shouldn't have to worry about "non-magnetic when you have precise temperature control.
Click to expand...

Yep it is an Evenheat with the digital controls and everything. That sounds like a pretty good gameplan to me as well. I wasn't sure if it was better to put the blades in when the oven is cold or when it's already hot.

Thanks to both of you!
 
DO NOT PUT THE BLADES IN THE OVEN TO HEAT UP TOGETHER.

You will overshoot by hundreds of degrees every time, guaranteed. Even with a slow ramp up program.

ALWAYS allow the oven to equalize at your desired temperature, before putting them in. Quickly but safely put them in and once the readout has steadied again, start your soak clock.
 
Thank you Rick! I did some more research on my own last night and saw that as well. I appreciate the heads up!
 
The time it takes to initially heat up to target temp will depend on the size/thickness of the blade. I think somewhere around 1 minute per millimeter (or .030”) of thickness should generally be sufficient. I typically do smaller blades, so I’m adding about 3-5 minutes to the soak.
 
J. Hoffman said:
Do you have a digital controlled kiln? I usually put the blades in cold and let it ramp up to temperature. I hold at that temp got the soak time. If the soak time is 10 minutes, I usually set the timer for 13 minutes, which gives me a little time to quench all the blades. I don't usually do more than 5 blades at a time. You shouldn't have to worry about "non-magnetic when you have precise temperature control.
Click to expand...
And you don’t have any problem with the oven over shooting and then stabilizing to the right temperature?
 
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