Stainless foil question

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bjalongi

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Oct 23, 2006
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Does anyone have pictures of how they fold their foil on a blade for heat treat? My method has yielded several failures and I consistently bend the blade trying to remove it. The foil I have is rather thick. I'm so discouraged by using foil that I'm probably going to start using something else.

Thanks.
Brook
 
Brook
All I do is fold a piece in half,place the spine on the fold,then fold all open ends over twice.then bring up to heat and place the packet between aluminum plates when cool remove.You don't need to remove them from the foil to air quench.
Stan
 
That is basically all there is to it. Some tips:

Don't let any folds go over the blade.
Press out most of the air when folding.
Gently but firmly,tap the folds to seal them, with a rubber mallet.
Be careful, stainless foil is just about the same as an 18" wide razor blade.
Stand the foil packet(s) in a rack ,spine down, in the oven.

Stacy
 
That is how I've been doing it, and I have had my share of foil cuts.

Is stainless foil best used with air quenching steels? I can't get the foil off fast enough to do an oil quench before the blade cools too far. Either I bend the blade when I'm trying to rush and burning my fingers through the gloves, or it cools too much and I have to start over.

I use 1095 almost exclusively now, so air quenching is not an option. Since I built my new forge I have to use some sort of scale prevention method. I should of hung on to my old forge just for heat treating, because it had an almost perfectly neutral atmosphere.

Perhaps I should consider a different product. A heat treat oven is currently about a year out.
 
A heat treating oven almost certainly has a worse atmosphere than most forges for heat treating. Lots of free oxygen. So you need scaling protection even more.

Other than that, they're great.
 
Brook,

How it's been described is exactly how I do it as well. Make sure, as Stacy pointed out, not to overlap the fold on the tip of the blade as it will warp away from the bulk on one side of the tip. Foil is best for air/plate quenched steels as you guessed. It's often just too difficult to cut the packet, get the blade out, and quench under control. I've heard of people cutting the packets and just dumping the blade out into the oil, but that makes me cringe a bit. For oil quenching blades, use Brownell's product or even make a thin slurry of satanite and water, dunk the blades to coat them, and then heat treat. I've heard that works pretty well for a lot of folks.

--nathan
 
How come you can't just quench the wrapped blade in the oil straight from the forge/oven? I'm not being a smart-alec, it's an honest question. :)
 
I just did 5 1095 blades in my electric kiln and did not use any foil and got realy clean results. I had alot more decarb in the forge. due to the quick quench needed I dont think you can use foil on 1095, if you leave it on the oil will not get to the blade, if you take it off you are already too cool.

For Stainless or A2 (both air quench) I leave enough room at the top to cut foil open with a pair or metal shears, Grab with a plier and on to the plates. I usually dont plate quench in the foil because I have the bevels ground and my setup is not self squaring enough to get even pressure.
 
A2 plate quenches fine in the packet. You don't have to worry about time with A2 you have about 950 seconds to miss the Pearlite knee and about 1050 to miss the Bainite field, see: http://www.bucorp.com/files/aisi_a2.pdf

I believe the CCT diagram is on page 4.

I fold longways put the blade in then fold both ends then fold over the long side then refold the ends and the long side so each is folded twice and locks the other. make the sheet large enough to have all of the seams off the blade
 
Patrickknives said:
I usually dont plate quench in the foil because I have the bevels ground and my setup is not self squaring enough to get even pressure.
Click to expand...

I address this issue by using drops of the steel I'm using to put in the four corners of the lower quench plate. The upper plate held up with a chain. Hot knife goes on, I lower the top plate, the drops in the corners keep it level, and then apply more weight. I pull it out after about eight seconds, cut the foil open and straighten the tips before Ms.

Works every time.
 
I plate between the aluminum still in packet with just the butt end of the knife and packet hanging out of the plates. I then clamp the plates together, and once all the color is out of the blade and packet, I snip the exposed foil to open the packet. Then, after the 8 or 10 seconds, I can grab the end of the knife and pull it out of the packet pretty quickly (occasionally the foil will stick) and straighten it out (never really have had to straighten a blade when it was correctly wrapped and plated, though).

--nathan
 
Thanks for the info on A2, I did not have anything so complete.

I need to take the time and reconfig my plates. I like the idea of some guides at the corners.
 
Patrickknives said:
I just did 5 1095 blades in my electric kiln and did not use any foil and got realy clean results.
Click to expand...

Interesting. My first HT in the new oven (a few years ago) was O1, not 1095. The results were pretty ugly and several people here said that I really need something to prevent scaling. Got some PBC from Brownells and the problem went away. Well, mostly away, I've had trouble getting PBC to stick to really thin blades -- that's a large part of why I switched to A2 and plates.

Now that I've started forging I'll be using PBC-ish stuff again. Just got a jar of the new liquid and will try that before the powder.
 
bjalongi said:
Thanks Mike. I'll give it a try.
Click to expand...

As mentioned, this is a liquid. I use tinner's brushes to put it on, making passes using the side of the brush to smooth it. I keep the lid taped and in another good sealing jar so it doesn't dry out. Water can be added to dilute it (can be sprayed) so if it gets thicker, it can be thinned. 5-15mils. (thousanths of an inch) is all you need. Water clean up of the brush... I'll never go back to the powder again.

Mike
 
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I have heat treated stainless damascus that was oil quenching right in the foil packet. When it's warm to the touch I take it out and make sure it's straight.

A friend of mine paints his blades with white out? I have not tried it but I could see where it would work for oil hardening steels.
 
I tried white out once, on a set of 4 blades. It was an all around disaster. Of course all the problems might be mine not the white out but I sure don't plan to try it again myself.

There's a thread on here about it somewhere. A couple of years ago.
 
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