foil sticking

[elementfe]

I guess I'm hoping and grasping at straws- using a borrowed kiln, I did a batch of foil wrapped folder blades and when I pulled them to plate quench, the foil looked burnt, and stuck to the blades in many places.
Two of the small blades were touching inside a packet and stuck together...popped apart without too much trouble.
I've used the exact same foil and oven several times and been happy with the results, the only difference is that previous blades were 440c, and this batch was CPM 154...temps the same, the thermometer never read over 1900.
Has to be a faulty thermo control, I'm guessing, is there any other explanation?

Thanks for any thoughts or ideas
Andy

[daizee]

sounds like holes in your packets allowed air in. Possibly the corners of your folds were over-crimped?
I've found a little sawdust acts as buffer between the foil and blade to reduce sticking in addition to burning up the atmosphere inside the foil, which was the reason I was instructed to do it in the first place.

[elementfe]

Thanks, I never thought of that- I crimped the edges with a little mallet, and now that you mention it, didn't use anything to consume the O2.
Perhaps I was being over zealous about crimping and defeated myself...hate when that happens!

[SteelSlaver]

I had that problem. Was using good foil and making sure the packets were sealed up. Had some bad sticking problems. Was sticking the blades in stainless pouch real clean. Then I started wiping each blade very lightly with WD40 and have never had another problem. I think if your pouch is real dry and clean and your blade the same and the are pressed against each other a bit, they actually start to weld even if the temp is 1850, you do have a fair amount of soak time.

[elementfe]

Thanks for the feedback- I was pretty sure that this unit must be defective, and me still saving up for my own!
It didn't seem like it was overheating, since the edges tested really good on previous batches- but good point about the cleanliness- these blades were pretty smooth, and very clean. I guess a little "contamination" is a good thing sometimes, huh?
Like a lot of things in life-

[darrin sanders]

Here is what I suggest. Do not reuse foil. Double wrap each blade. When you do the first wrap put a little baby powder on each side of the blade. The baby powder is talc which is powdered rock and the heat will have no effect but the foil will not stick. Double wrapping will insure that the blades are clean as a whistle. I do a lot of H/T'ing and this works well for me. Hope this helps.

[elementfe]

Thanks, Darrin.
These were double wrapped with new foil, but the blades were clean and I didn't use anything inside the foil. Talc sounds like a good idea, thanks!
Andy

[elementfe]

Postscript: When I went to clean these up, they were all badly warped. Packets were evenly spaced, standing on their edges.
I'm guessing that the thermostat on this unit is bad, but I don't really know what to think...
Does CPM 154 have more of a tendency to misbehave? This setup worked very well with 440c, several times...
This is the piece of CPM154 that had hard spots- I think- unless it's somewhat more prone to work hardening than similar steels...has anyone gotten a piece of this material that wasn't that good?
I'm assuming operator error, but it's kind of tricky to trace down.

Confused...
Andy

[jakehobackknives]

Double wrap, light dusting of talc. No more sticking.

Keep in mind, if your temp never got above 1900 you may not have gotten a good hardness from that 154