Stainless foil wrapping for heat treat

M

Mickey

Joined
Mar 17, 1999
Messages
224
Is it safe to wrap more than one knife in a foil packet for heat treat? I am still experimenting with a new Paragon oven.
 
In many cases, yes, you can do a bundle of blades. Make sure you add extra soak time..

Controlling factors:
1) How many blades?
2) Only profiled or fully ground?
3) Steel type?
4) Quench method?
 
If I'm doing something small like a neck knife, I'll often do two in a single packet, but I make sure that they stay separated, and that I can still easily press them between my quench plates. I haven't had any warp issues when doing it this way.
 
I'll do a couple small knives if I can get them next to each other so that they get equal surface area on the quench plates, and aren't stacked on top of each other.
 
Thanks for the reply guys. Long time Knifemaker, but I bought a Paragon oven in march and I am still experimenting.I manly do stock removal with stainless steels.Plate quenching with compressed air.Dry ice cryo.
 
Would stacking have any effect on the quench time between the plates, where the center cools slower than the outside, changing the outcome some (if any)?
What is the max thickness you can stack without negative effects (if there are any)?
Those of you doing it, what’s your max stack?
 
In answer to your question, quench speed is not much of a factor with the stainless steels we use .... preventing warp is our problem. You have 30 minutes or more to cool the blade down to room temp. Still air will do that. The drop from room temp to cryo/DI should continue and then tempering. No rush in any step. The things folks do that seem to need it done quickly are usually where warp starts or sets up.

Most of the time I do a multi-blade envelope they are side by side. Two or three kitchen blanks side by side are set on the plates in the packet and pressed together.

I do bunch oyster knives in bundles of 10. I cut the end off the packet and slide out the blades onto the quench plates. They are all the same thickness, so the press keeps them all down to prevent warp as the cool.
 
I've tried to do multiples but I have more issues with warping. I didn't think about trying to take the blanks out of the foil to plate quench though. That may help.
 
It seems for me anytime one side of a blank has a quicker cooling rate I get more warp, especially when the steel is immediately removed from the oven and really glowing hot. With quench plates I try for contact with both sides of blank at almost same time and I find I have much less if any warp.
 
I've been doing 2 blanks side by side in packets and try to form the packet tightly with my kydex press so I can see the blade imprint to help keep them from slipping on top of each other. I also started going from the oven to the plates a bit slower to let the blade cool down a little bit first before it lands on the plate. I have a bottom plate set up, put the blades on the bottom plate and then put the top plate over the blades and clamp, so there is time between the contact with the 2 plates, especially if I am doing multiple packets with smaller blades (my long plates are 30" long, so I often do 2-3 blade packets per quench). The longer delay seems to help with warping. Got very little warping this way with some 1/16" AEB-L I did recently. I stacked up the 1/16" AEB-L blanks so they were 2 deep. They are completely unground and rectangular, so they have good contact for quenching and I hit 62-63 after cryo and tempering. If it's 3/32" or 1/8" or thicker, I don't stack up.
 
Taz said:
I've been doing 2 blanks side by side in packets and try to form the packet tightly with my kydex press so I can see the blade imprint to help keep them from slipping on top of each other. I also started going from the oven to the plates a bit slower to let the blade cool down a little bit first before it lands on the plate. I have a bottom plate set up, put the blades on the bottom plate and then put the top plate over the blades and clamp, so there is time between the contact with the 2 plates, especially if I am doing multiple packets with smaller blades (my long plates are 30" long, so I often do 2-3 blade packets per quench). The longer delay seems to help with warping. Got very little warping this way with some 1/16" AEB-L I did recently. I stacked up the 1/16" AEB-L blanks so they were 2 deep. They are completely unground and rectangular, so they have good contact for quenching and I hit 62-63 after cryo and tempering. If it's 3/32" or 1/8" or thicker, I don't stack up.
Click to expand...
I'll have to give this a try as well. Saving time and foil is always good.

Overall, im starting to think that I might be in too big a hurry to get the steel in the plates.
 
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