basic heat treat questions

[stevenbusch]

When I was trained it was always pounded into my head that when heat treating a blade , always point the blade down. That works fine if you are using a pottery kiln from the top. My kiln, Evenheat 22.5 is not tall enough. Now the question...should a blade be placed on it's spine, edge or flat, or does it really matter? I am talking ATS-34, 154cm, 440c etc. I would hate to end up with a blade that goes around a corner after being heat treated. I know I get really ****** when I am almost done with a blade of damascus and a weld breaks, snapping the last 20% off. I can olny make sooooo many screwdriver blades of damascus.

Second question/......can a firebrick be used as a holding rack or would this cause uneven heating.

Thanks for any help

Steve Busch

[Don Cowles]

A slotted firebrick makes a fine rack, prov##ed you make some clearance under it so you can pick it up with a "pizza shovel" or some other tool used to remove the rack when it's time to come out of the furnace.

I also have an evenheat oven, and process all of my blades on the spine. Be prepared to have the occasional banana; it does happen. If you catch it before it has cooled down, it is very easy to straighten.

[stevenbusch]

thanks for the info

Steve Busch

[Geno]

I put the edge up, spine down in a rack.
My rack is metal, brick works fine but is bulky.
Inconel makes the best racks.(nickel,chrome, and iron)
It can really take the heat.

If you get a warp, straighten it within 15 minutes of taking it from the oven.
It must heat evenly and cool evenly as well to prevent warpage.
S/S is best if you wrap it in foil, C/S is quenched and you will fight the envelopes trying to get it in the quenchant in time.
(And you WON'T make it in time )

[stevenbusch]

I have s/s foil on the way. I was reading somewhere that a double stainless wrap almost eliminates the heat treat scale. It was stated that a buffer will clean off the scale for the most part. I figure I will try the double wrap a time or two as a test.

Steve Busch

[Geno]

Hello Steve,
You might try sprinkling just a few pencil shavings in the bottom of the envelopes to burn the oxygen out.
I use old foil for one envelope, and some new for the other one, it saves on foil.
Make sure the blades are free of fingerprints, ect... before sealing the envelopes too.
Be extremely careful with the foil when handling it, it is wicked sharp on the edges.
Be blessed.

[stevenbusch]

Using the old is a good ##ea. I will try the pencil shavings also.

I have learned about the sharpness, the hard way...and I was even trying to not get cut. I guess it's like everything else when making knives...you get cut, stabbed and poked from time to time, with out even trying. Autos under construction are even more fun. I had a small 2 inch blade get away from me today and caught it in m## air....only a small hole in the palm of my hand.

Thanks again

Steve Busch