Argon vs foil

Fiddleback

Fiddleback

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OK, my furnace shipped yesterday (paragon) and so I ordered some heat treat foil. DANG that stuff is expensive. The Argon injection kit is only 200 bucks. Does it work as well? Is it worth it? How quickly do you use up the Argon? How much is Argon, and where do you guys get it?
 
A local gas supply company or welding supply should be able to deliver a tank to your shop or home. I haven't checked into prices, so I can't help you there.

The only problem I have seen with Argon systems is that while it protects you great while the blade is in the forge, once you open the door and remove the blade for quench, it is exposed to oxygen. So while the argon may work well for carbon/tool steel blades that are oil quenched where they are only exposed for a 1/2 second or so on the way to the quench, a stainless blade that is plate quenched will be exposed to carbon-scavenging oxygen for a significantly longer period of time while it is at heat.

So argon would work very well for oil quenching steels by preventing decarb on steels we normally don't foil wrap, but for stainless, I'd still use foil.

--nathan
 
So you take your stainless blade out of the furnace, wrapped in foil, and plate quench it while still in the foil??? Do you check for straightenss?

I use mainly 01, and thats what I bought the furnace for, but I thoght I could give some 440C or something fairly simple a try also.
 
I think the argon would work great for O-1; in fact I've considered rigging up a system myself. It would definitely keep the blades cleaner.

I wrap my stainless blades in a single layer of ss foil, double crimp the edges, and pop 'em in the oven. I used to put a small bit of paper in the packet to scavenge oxygen, but I got a packet or two that puffed up, so I stopped doing that. Whatever oxygen is in the packet really isn't goint to do any harm if you wrapped it tightly and have a good crimp.

I do plate quench in the foil. I sandwhich the packet on the plate with just the butt end of the packet exposed from the plates. After the blade and packet have stopped glowing (somewhere below 1200), I snip the packet open, grab the butt with pliers, and pull the blade out to check for and straighten warps. If all is well, I re-plate out of the foil and leave it until it's room temp.

A tip: be cafeul that the crimp doesn't overlap the tip, or it will cause a warp once the plates tighten to it. As long is it's only one or two layers of foil, it won't really slow down the plate quench to any noticable degree.

Again, for O-1, argon injection would be an awesome setup, but I'd definitely use foil for stainless.

--nathan
 
silver_pilate said:
I wrap my stainless blades in a single layer of ss foil, double crimp the edges, and pop 'em in the oven. I used to put a small bit of paper in the packet to scavenge oxygen, but I got a packet or two that puffed up, so I stopped doing that. Whatever oxygen is in the packet really isn't goint to do any harm if you wrapped it tightly and have a good crimp.
Click to expand...

Yep yep ! Had one puff up on me too ! Guess it was *too* much paper !

silver_pilate said:
I do plate quench in the foil. I sandwhich the packet on the plate with just the butt end of the packet exposed from the plates. After the blade and packet have stopped glowing (somewhere below 1200), I snip the packet open, grab the butt with pliers, and pull the blade out to check for and straighten warps. If all is well, I re-plate out of the foil and leave it until it's room temp.
Click to expand...

:thumbup: It's good to have a vise around just incase something WARPS!

silver_pilate said:
A tip: be cafeul that the crimp doesn't overlap the tip, or it will cause a warp once the plates tighten to it. As long is it's only one or two layers of foil, it won't really slow down the plate quench to any noticable degree.

--nathan
Click to expand...

Damn ! I think you just solved what the heck i did wrong last week on this one blade ! i was like WTF? how did the area towards the tip get all screwy like that!

I'd go with the foil. All this gas, etc etc..seems a bit crazy.

Is Argon toxic?
 
Argon isn't toxic, but it isn't life sustaining either. It is inert and is heavier than air, so it could theoretically fill and small room from the floor up and displace enough O2 to cause you to pass out without knowing why and die on the floor covered in argon from oxygen deprivation. But in a shop size area with decent ventilation, it's not a problem...especially with the slow flow rates involved with flooding and maintaining an inert atmosphere in an oven. I can't really imagine a scenario that would cause argon to really be dangerous short of opening the spout wide open in a very small, poorly ventilated room.

Leu, glad I could help! It ran around my head long enough after I had a tip warp on me that I finally figured it out. The crimp was large enough and the metal soft enough that it bent away from the crimp while in the plates. I leave about 1/4" or more space between the edges and ends of the knife and the crimp now.

As for having a vice around, get some smooth jaws in it, or you'll have nice cross-hashed impressions on the blade from straightening (ask me how I know :o). I have a really small vice that I have mounted on the edge of my work bench that I use to straigten any warps now. It has smooth jaws and is just right for little corrections. Otherwise, it's a light hammer tap on the anvil of my big vice.

--nathan
 
My oven has an argon tap. I used to use it, but I figured foil is less expensive. I only use it now for parts that don't lend themselves to foil.

Also, the finish on an air quench steel can be damaged from the air during the quench. There isn't time for any real decarb concerns, but if you take your blade up to near full finish before HT, foil does help protect it better.

The way I do it: Double crimps, away from the blade, no paper or anything, plate quench, pull out after about 8-10 seconds and remove from foil to straighten any kinks with gloved hands. Stop messing with it once it starts to "set up".

Be careful with foil. You can cut the piss out of yourself in a second. I wear Kevlar gloves. A good $7.00 investment. Better than my other investments today... feh...
 
Yeah, that SS foil can slice you up real quick. Gloves and a good set of shop shears/scissors, and you're all set.

For the crimps, I use a block of micarta and a hammer to flatten it out. I make my first fold on the three sides and flatten them well with the micarta and hammer. Then make your final fold and and re-flatten with the micarta and block. Be careful not to puncture the foil with the micarta or with your pliers during positioning in the oven or during crimping. If you try to crimp too close to the knife, you'll likely tear the foil. Give yourself a small amount of space all around the knife, and keep your crimps thinner than the ricasso/tang thickness.

--nathan
 
Thanks guys. All these tips are good. I've used metal foils before during my engineering days, so I know to watch for the cuts. Really appreciate all the help.
 
Fiddleback said:
OK, my furnace shipped yesterday (paragon) and so I ordered some heat treat foil. DANG that stuff is expensive. The Argon injection kit is only 200 bucks. Does it work as well? Is it worth it? How quickly do you use up the Argon? How much is Argon, and where do you guys get it?
Click to expand...

I think I ordered a roll of SS Foil back in 2006 from Texas Knifemaker's Supply back then ($145.00) now ($170.00).

150 or so blades later and i'm probably only half way through the roll. So it's not too bad :)

Lyon Industries (which carries aluminum and other types of Shim Stock) has stainless steel foil 24" x 100feet probably cheaper than most places i've seen around.
 
Caution! Lyon only lists the 321SS tool wrap. It is rated to 1800F and most stainless should be done in 309SS.

Caveat Emptor.

Rob!
 
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