Blade Steel Rehardening

Are you working with salts? When I can get started up again, I need to finish my controllers for my high and low temp tanks. What I'm thinking of doing for the low temp is just stick the horizontal tank in a home made electric furnace (which I need to build). My high temp is a vetical made from SS pipe from Ellis in a large forge made from an old water heater with kaowool/satanite/ITC lining. Was using venturi burners and propane, but I want to try waste oil with a blower.
 
hardheart said:
Are you working with salts? When I can get started up again, I need to finish my controllers for my high and low temp tanks. What I'm thinking of doing for the low temp is just stick the horizontal tank in a home made electric furnace (which I need to build). My high temp is a vetical made from SS pipe from Ellis in a large forge made from an old water heater with kaowool/satanite/ITC lining. Was using venturi burners and propane, but I want to try waste oil with a blower.
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I wish I could... but the salts are out of my budget. Multiple salt containers would be needed as each type of salt only works within a few hundred degrees, and each salt is $200 a pack, so the costs pile up. A salt bath would be nice though, I want to make one eventually.

I like your idea of using electric coils for heating. The coils need to be kept a distance from the steel salt container or it can arc, though. It would be great if you can pull this one off.
 
For high temp, I was doing a 50/50 of sodium & calcium chloride, super cheap. My low temp is heatbath stuff, 300-1000 F.
 
cotdt said:
Yeah I've done folders but I'm not sure what steel they use in the SAKs. If it's 420 I won't be able to do much, 440A I can get to 59 rc. I like your idea though, I've been wanting a high performance SAK myself for a while.
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I have no idea what the steel is they use. I'd guess it would be one of the Sandvik steels, but your guess is as good as mine as to what it really is. Someone should make an M2 steel SAK Cadet. :)
 
Murphyslaw said:
I've got 2 pairs of possible candidates.

The first is a pair of Ontario Rat-1 folders (AUS-8), and the second is a pair of Gerber Freeman (IIRC) Caping knives (I've seen the blade steel listed as "high carbon steel" and 440A).

I would suggest doing the reheat treatment on one of each of the pairs, then respectively comparing the performance to the untreated ones.

What do you think?

Chris
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That AUS-8A sounds like a great idea. The before-and-after can be directly compared. Cool.

db said:
I have no idea what the steel is they use. I'd guess it would be one of the Sandvik steels, but your guess is as good as mine as to what it really is. Someone should make an M2 steel SAK Cadet. :)
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Meh... so we don't really know what the steel is made out of. Every steel has its own heat treat formula, so the identity has to be known to be heat treated. Although I can clone the blade with some of my CPM-M4 stock :D That would be a rather involved project.
 
db said:
I have no idea what the steel is they use. I'd guess it would be one of the Sandvik steels, but your guess is as good as mine as to what it really is. Someone should make an M2 steel SAK Cadet. :)
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I've been thinking about doing that. I've got some power hacksaw M2 HSS blades, but I later found out through a fellow forumite that the thin blades are not at 66 HRC like the thick ones. If I could cut out some blanks then have it re-heat treated..... Hmmmm.....

I wish rec.knives hadn't deteriorated so much, I haven't talked to Alvin in years...
 
sodak said:
I've been thinking about doing that. I've got some power hacksaw M2 HSS blades, but I later found out through a fellow forumite that the thin blades are not at 66 HRC like the thick ones. If I could cut out some blanks then have it re-heat treated..... Hmmmm.....

I wish rec.knives hadn't deteriorated so much, I haven't talked to Alvin in years...
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You can just grind the blades and use as is. It doesn't need to be heat treated again. Alvin just used them as is.
 
Yeah, but the thin stock that's useful for small blades such as SAKs and other slipjoints is down there, scratched easily by files. I'd want to get them up to the levels that my thick M2 blades are at, for performance purposes, around 65 or 66.
 
sodak said:
Yeah, but the thin stock that's useful for small blades such as SAKs and other slipjoints is down there, scratched easily by files. I'd want to get them up to the levels that my thick M2 blades are at, for performance purposes, around 65 or 66.
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Yeah those thin M2 blades are rather flexible, like a noodle. If you grind them out and send it in, I can get 66 rc for ya. ;)
 
Cot, if you get ready to do a run of S110V please let me know. I have a spare that is just dying to turn into the monstrous steel that is lurking within. I know it's pretty high temps so if you're not comfortable, I wouldn't blame you a bit.

I've been wanting to get it done since Gator first posted his thread. It's NIB. Do I need to prep it in any way?

I'm mastiffone@hotmail.com

or, the e-mail link is old but still operational. This is a great offer Cot, and I thank you for it. Yep, I know there are risks, but as for you as a person, I have no hesitation whatsoever. Joe/Raleigh
 
By the way, I have a nice sized chunk of S125V annealed and waiting for a project. Just thought I'd throw that out there. :)
 
I don't have anything that needs re-HTing, but just saying THANKS! to cotdt for this free service :D
 
I don't understand this thread. There is nothing an individual can do to the heat treatment of a purchasezd blade except ruin it. This seems like a bizarre idea to me -- an unworkable solution desperately searching for a nonexistent problem to solve.
 
Sharp Phil said:
I don't understand this thread. There is nothing an individual can do to the heat treatment of a purchasezd blade except ruin it. This seems like a bizarre idea to me -- an unworkable solution desperately searching for a nonexistent problem to solve.
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What makes you so authoritative? Materials engineering training? Degree in metallurgy?

What's the difference between a custom maker doing these steels (e.g. Phil Wilson, from whom cotdt has taken his cues, apparently) and redoing another company's treatment? Unless you assume that the company chooses the best treatment for every individual user's usage and nails it exactly, what's the problem with re-treating it? If proper precautions are used (stainless foil wrap, etc.) there won't even be any appreciable decarb or scale.
 
Sharp Phil said:
... There is nothing an individual can do to the heat treatment of a purchasezd blade except ruin it.
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Thank you very much for your concern :) Contrary to your statement, I did have several blades rehardened and I'll be happy to stack them up against your "purchased blades" any time.

Sharp Phil said:
This seems like a bizarre idea to me -- an unworkable solution desperately searching for a nonexistent problem to solve.
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Besides, what is exactly that you don't understand, it boils down to very simple numbers and heat treating according to very well defined rules, which rehardening guys didn't invent, but it's rather manufacturers not following them and underhardening for their specific reasons.

Is it personal or you are against the concept of rehardening? Because several well know makers do reharden factory blades and I take they have a lot more experience in that area than you do.

Using your logic, one could use exactly the same argument against regrinds, is that so?
 
This is a great thread and Cotdt is doing a very good thing.
He is trying to let steel go for it's best performance.
I can see his point, as this is my reason why I began to make knives by myself.
I, too wanted steel to perform as good as it can go.
 
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