Evenheat Kiln + Argon

[twistedneck]

I'm about to purchase a Kiln from Evenheat. I'm going to use the peep hole to setup a simple argon system. Any ideas would be appreciated.

Also, what is an Inconel retort? Do I need one for the 22.5" deep kiln?

Thanks, Jeff

[twistedneck]

After some research, a retort is just a box inside the kiln that contains argon - you heat the entire box with the part inside in pure argon. This protects the burners and thermocouple shield from heat when they loose the protective oxide layer in argon. I simply don't need that as i'm tempering in a salt pot and only need the argon for complex shapes (not knives).. foil will work fine for knives.

Evenheat does not recommend the argon, but as long as you know burner life will be diminished (its $40bucks for new elements) then your ok.

Will drill a hole in the upper back side of kiln, making sure to miss anything of importance, have extra cement for repairs to the inside brickwork. the door hinge is not sealed well, it will be the primary vent.

Using a 40lb argon tank, regulator and needle valve at the kiln. Going for 2CFM steady state only when the part is actually in the kiln.

I will have pics in a couple weeks when its all setup. Mike at evenheat was really helpful.

[RJ Martin]

Twisted neck: I'm curious about the condition of the blades when they are removed from the Argon environment and quenched. Is there any scale?
Also, are you heating multiple blades at once and then removing them one at a time?
Finally, how much Argon do you go through in a HT cycle?

[twistedneck]

RJ, I will find out next week when i get the kiln and run trials. Just got 3 240V 20A electrical drops today, a huge powered basement vent, etc - i also upgraded two outdoor 8' copper ground rods. I don't want to kill myself with argon, hence the vent.

I will publish all of my tryout data including scale pictures. That should help out, i've read 2cfh is what Paragon recommended over 800F, but that rate seems a bit high.

[Jeff Pelz]

Jeff,

A knifemaker that I vist quite often, uses argon in his Evenheat oven. He has the 18.5" oven and wishes for the larger oven just for larger blades. He uses a inconel retort, which was cu$tom made for his oven. I beleive the gas was fed from the bottom. The retort sides in and the supply tube drops into the hole drilled into the bottom of the oven. He only uses the argon for some of the CPM steels, 154CM and 440C. What PSI he uses for the Argon I don't know. All the other CPM and Timken steels are bagged. He is planning on purchasing a larger oven and says he is going to try and fill the entire oven chamber with argon, without the retort. But will use a inconel supply tube to feed the oven and make the connections to the supply line. The tempture probe and fire brick repair, has been the only items replaced on his Evenheat oven.

Best regards
Jeff Pelz

[twistedneck]

Jeff P, why does he only use argon for the CMP steels? If he uses stainelss foil for the rest..

Do you know by chance how he figured out the probe was bad? I receive the KF22.5 first week of March due to a backlog.

I want to use a 1/4" inconel tube inserted all the way into the brick. I'll get the end flared at the hardware store and link it to copper up to the argon tank. I bet the hardware store doesn't carry inconel tube sections. LOL I bought extra cement, i got 3' of KO wool 1" to wrap the kiln to prevent burns.

Looking forward to some high heat!!!

[Jeff Pelz]

Jeff,

I made an error with the information on the previous post, Sorry. He uses the argon for the heat treating the 154CM and 440C. At tempatures in the 1900 range. There was a whole lot less decarb to grind off when argon was used with these steels. But with any of the higher temp heat treatment he uses the high temp foil. But there is a chance of a stainless foil bag twisting a knife, melting to the blade steel or having a lot of very hard decarb to grind off.
He uses CPM steels as his primary blade steel, because of the high hardness and the percentage of Vanadium. But has just recently started using some of the Timken steels, 20CV and A11. There has been some positive results with these steels.

JP