Roll Your Own...S30V

Well said, Steve! You seem to have experienced some of the same stuff I have. I had the opposite problem, though, in that the temp was actually 50F hotter than the pyrometer displayed once the probe got old! Either way, it sucks. The more I learned about thermocouples and the chaotic, non-homogeneous conditions inside our furnaces, the less I trust them. They need vigilance if we want to maintain consistency in our work. I strongly recommend that second probe close to the blades and an external meter to anyone using a furnace for HT.

If it helps any, $21 for the themocouple wasn't so bad compared to the $80 Omegas I buy to profile the inside of forges. Hi-temp (2500F), 3/8" dia, 18" long Inconel type K's are pretty pricey, and they still oxidize. Plus, one time over max temp and they're shot. Considering the blue cone of the flame can be hot enough to melt steel, one has to be pretty careful where they put their probe, so to speak! ;)
 
$80 = ouch.

You know Mike, one thing I was thinking about was using firing cones (like for ceramic kilns). They're cheap and accurate and come in a variety of temperature settings. Pop 'em in the oven with the blades and you can tell if you're over or under temp.

Just a thought

Steve
 
I have been prepping my blades for H/T the same way since I started, so I don't think that causes the "occasional" problem of sticky pouches. I WD40 each blade and then wipe dry, add a toothpick to the pouch, and start the ramp to the hold temp.
As for testing temperature: Hardness is the best indicator I have found for making sure everthing is going as it should.I have a Wilson Rockwell Tester and I test every blade after H/T and after each draw. I don't use that many steels (mostly tool steels) and I use the same steel source once I've settled on a steel's performance.
I had a problem (overshooting set temp by 25 degress) with hysterisis several months ago. I contacted Evenheat and the put me in touch with the people who make the contoller chips. They sent a new chip and the problem went away. Lower temps (400-600) have a little more variation (10 degrees usually on the high side) than high temps.
 
Gene ask AA about the foil sticking to the blade, He can tell you what not to degrease with.Say you and David are welcome to stop by when you go to Richards place. Mike
 
Gene Ingram said:
I have been prepping my blades for H/T the same way since I started, so I don't think that causes the "occasional" problem of sticky pouches. I WD40 each blade and then wipe dry, add a toothpick to the pouch, and start the ramp to the hold temp.
As for testing temperature: Hardness is the best indicator I have found for making sure everthing is going as it should.I have a Wilson Rockwell Tester and I test every blade after H/T and after each draw. I don't use that many steels (mostly tool steels) and I use the same steel source once I've settled on a steel's performance.
I had a problem (overshooting set temp by 25 degress) with hysterisis several months ago. I contacted Evenheat and the put me in touch with the people who make the contoller chips. They sent a new chip and the problem went away. Lower temps (400-600) have a little more variation (10 degrees usually on the high side) than high temps.
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WD40 certainly shouldn't have anything in it to turn acidic with heat.

You're a man after my own heart with that Rockwell tester. When I finish a HT and draw it looks like a woodpecker's been working on the tang!

Thanks for info on the chip, too, Gene. I hope I remember this if the need arises. As far as the hysteresis, yes, it will be greater at lower temps based on what Paragon engineers have told me, plus, the pyrometer is less precise at those temps and there is a greater variation versus setpoint down in that range of tempering temps. Like has been mentioned earlier, it simply means we have to work things out for our specific steels and furnace. That's why I don't share temps anymore on HT.

Thanks, again. Hope you can make the occasional welding thang go away.

Steve, I have a bunch of the cones in various temps, a whole range of them. The problem with them is that they are sort of "interpretive" in their behavior. The directions, after I received them, said that they are not only indicative at temperature, but also after a certain time at temp, too. If they're puddled they mean this, if partially melted, it means this, blah blah blah. It was all very confusing. If you'd like some cones, let me know and I'll send you some. I had to buy 50 each, and I'll never use them all. Maybe it'll make sense to you.
 
Mike, dang another perfectly good idea, tried by someone else and found wanting. Dang. Thanks for the offer, but now I'm not so sure it's a keen idea.

RE: woodpecker in the shop

Hurray! It's not just me. Maybe it's cause I think the tool is cool, but I end up taking a few readings after each step. I think it's the mystery of the whole process, but I really get a kick out of 'seeing' the steel transform.

RE: the main question in the thread

I wonder what kind of foil I have!? I get it from K&G and they don't have choices. Mostly I just trust those guys to weed thru the various options and sell me what works.

Steve
 
Sando said:
Thanks for the offer, but now I'm not so sure it's a keen idea.
Steve
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Are you sure? Just because it's a bad idea doesn't mean I wouldn't want you to try it. :eek: Misery loves company, neh? :D

Gosh, I wish you all were gonna be in Chicago this weekend at the show. We could generate some fine chuckles, I'm certain!
 
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