SS wrapping puffy

Alden Cole

Alden Cole

Well-Known Member
I am heat treating some ss knives, (D2 and 440c), and my ss foil wrap around the knives is puffing out, when normally it sucks in tight to the knives. I put scraps of paper in with the knives to burn up any oxygen like I usually do. Anyone ever get puffy foil pouches? I hope this makes sense. The D2 knives look fine and normal out of the quench, the 440c are in the oven right now.
 
i was getting that for a while. No matter how flat i got it when I sealed it, the foil pouch was blowing up like a balloon. I had been putting paper or a Q-Tip in there to burn and it seemed to be doing just the opposite of what I wanted.

Then I started degreasing my blades real good and the problem went away. I haven’t put anything in there to burn lately and they’re doing great. The blade looks vacuum packed coming out of the quench plates and the blades are bright.
 
Thanks John! I didn't wash off or degrease the blades before wrapping them. Could it be that the oils are transferring to gas and expanding in the pouch? Makes sense to me. I guess I will start degreasing and see if that solves it. I'm guessing there is nothing wrong with these blades though right?
 
I've never had problems of the pouches puffing up, I don't know what would do that but I wouldn't worry about it.
your using 440-C, I never had any problems of any sort with that but if you start using steels that go towards 2000 degrees
I highly recommend dusting the blades with baby powder-the pure talc kind, not corn starch.
when I started using CPM-154 I was having the stainless wrap weld to the blade in spots and trust me, you don't want to experience this.
it just about wrecks your blade.

I've tried the small pieces of paper and what-not and never saw any difference so I never do that. but you do want to clean your blades as best as practical with acetone or alcohol.
but trust me on the talc dusting it does work, and it works good.
anymore, any stainless blade going in the oven gets dusted before wrapping in my shop. it's cheap insurance the knife comes out the same way it went in.
 
I put paper in to get that puffy envelope. My experience has been that when the foil shrinks up tight all the way, it either sticks or warps the blade or both especially on thinner stock folder blades. The cleaner the blade is from oil, junk etc helps. Some guys use dykum layout fluid on their blades and it works well for them. Like Steve Miller mentions above, having the foil stick so hard you have to grind it off is really a hassle. I also dust the blades with talc.
 
I must be abnormal because I give it a shot of WD-40 before I do th top seal. I used to do kraft paper or similar then had trouble with them sticking to the foil. I Like the puffy so I snip the end and makes it easy to extract them faster.
 
When I make the envelope, I also make a red x on the handle end. I remember years past When a friend heat treated some blades for me and the bevels had an indent in them. Duh he had pulled them out blade first and the pliers while red hot had dented them.
 
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