Heat treating with stainless foil - tip 👍

[JV Knives]

Hi gents,

Recently, I heat treated a pair of CPM 3V blades and found a good example to illustrate how to NOT do it

Below, you will see 2 packets as they came out after austentize. However, one of these items does not belong with the other notice the small tear by the tip of the marker.


Note this puncture was from the tip…but this can happen on any sharp corner. The root cause…trying to use a piece of foil that was a tad short and “making it work”

Of course…the expected results. Blade shows much more scale and was a bugger to clean compared to the cleaner twin.



All recoverable but those of you who work 3v know that the descale is tough as nails. So…brothers and sisters …. Don’t skimp and be ever so gentle as you beat the seams flat on your stainless foil

Best!
John
JV Knives

 

[Contender Machine]

Been there done that…

Anymore I pull out what looks like enough foil to make a pouch for the blade. Then I pull out that much again and it’s big enough most of the time

 

[Lorien]

there's this guy I know, a machinist by trade, who lost his shit and blocked me on IG, who works for a mold making business which does a lot of heat treating. I made a typical post ht post with all the pretty colours and a small amount of decarb and a knife I'd heat treated, and he commented do I put a piece of paper in the envelope- to which I replied 'no'. He then told me that I might as well not even use an envelope, since I'm not burning away the oxygen inside. Well, that's ok, whatever...but I asked him what is left behind when you burn your little fire inside the envelope? He said just a little ash, but I pressed on and asked what else is left in there? That's when he lost it and blocked me. I think he was being over sensitive- I was just trying to get him to use some critical thinking. What atmosphere does fire create in a sealed envelope? Carbon dioxide and water vapour- neither of which are much better for your steel than the small amount of oxygen in there. It was a weird situation, since I didn't get a chance to get that far with him, not to mention any talk about the constituents of the stainless foil which are meant to minimize the oxygen once everything gets hot.

if I could, I'd direct him to this thread.

one time, I thought I was being clever by squeezing as much air out of my envelope as possible, but what ended up happening was the foil bonded to the steel that it was so tightly pressed against and created as much of a hassle for me as a bit of decarb. So now, I don't really sweat it- I get my knife in there and make sure it's sealed up really good, and if there's a bit of air in there I don't stress it.

I did try putting a piece of paper in an envelope once and it didn't seem to do anything good or bad

 

[JV Knives]

there's this guy I know, a machinist by trade, who lost his shit and blocked me on IG, who works for a mold making business which does a lot of heat treating. I made a typical post ht post with all the pretty colours and a small amount of decarb and a knife I'd heat treated, and he commented do I put a piece of paper in the envelope- to which I replied 'no'. He then told me that I might as well not even use an envelope, since I'm not burning away the oxygen inside. Well, that's ok, whatever...but I asked him what is left behind when you burn your little fire inside the envelope? He said just a little ash, but I pressed on and asked what else is left in there? That's when he lost it and blocked me. I think he was being over sensitive- I was just trying to get him to use some critical thinking. What atmosphere does fire create in a sealed envelope? Carbon dioxide and water vapour- neither of which are much better for your steel than the small amount of oxygen in there. It was a weird situation, since I didn't get a chance to get that far with him, not to mention any talk about the constituents of the stainless foil which are meant to minimize the oxygen once everything gets hot.

if I could, I'd direct him to this thread.

one time, I thought I was being clever by squeezing as much air out of my envelope as possible, but what ended up happening was the foil bonded to the steel that it was so tightly pressed against and created as much of a hassle for me as a bit of decarb. So now, I don't really sweat it- I get my knife in there and make sure it's sealed up really good, and if there's a bit of air in there I don't stress it.

I did try putting a piece of paper in an envelope once and it didn't seem to do anything good or bad

I have never tried the inserting of material to burn the o2 either but I don’t really feel it’s been necessary for me. If you take a look at the top packet on the left first photo, you can see it looks like it has pulled a vacuum from the heat. Even the drilled holes in the handle are visibly drawn in. That is my normal look. The baggy one on the right is the packet with the hole.

I have also played the peel the foil game from trying to get too much air out. I think the best result for me has come when I just get a good even sealed packet with adequate space

 

[bladegrinder]

I dust my blades with talcum powder before sealing them up. I had one blade years ago where the foil seemed to partially weld to the blade and it was a nightmare cleaning it up.
since using the talcum powder I've never had any problems.