What will a dry-heat autoclave do to the edge?

I'm taking a hairdressers' course here in Modena because I want to work part-time giving traditional shaves with a real straight instead of a disposable blade razor. The law says that some tools can be disinfected in barbicide but razors have to be autoclaved. Wet pressure autoclaves are relatively expensive but I found an economical dry-heat autoclave here. My concern is that it operates at at a high temperature compared to wet autoclaves, 473 °F (245 °C). Assuming that I used an all-steel razor (like a Wapienica), does anyone know what will happen to the edge of the razor, or the tempering of the whole razor, at that temperature?

Under 400°C, under one hour: nothing.

I'm not sure about what temps should be used, but I believe that Wapis' scales are stainless so that they can be autoclaved.

I woould be more concerned with the scales from heat than the blade itself. Although over time I would think stress hardening of the steel would come into play.

It depends on the steel and the accuracy of the thermometer on that device.

I've tempered razors at 500 deg. F and still had some pretty hard steel (around 58 Rc, which is in the range of most Euro and American straights). But that applies to the steel that I use, not necessarily whatever the Wapis are, though I'd be surprised if the difference were catastrophic.

But why do you need to autoclave your razors?

Oh, and there's very little data on how hardened steel reacts to repeated cycles at those temps. Two tempering cycles at 500 for 1 hour each leaves great results, but there's a possibility that you could drop a few hardness points with continued autoclaving. ( I think Spazola's frameback experiments showed that Rc 53 was still a usable hardness for razors, IIRC)

FWIW, tattooing needles in both high carbon and stainless steel are autoclaved in a steam clave at 265 degrees Fahrenheit. This is of course too low a temperature to affect the temper. Back when we used to re-use needles it was common knowledge that autoclaving (with steam) would have a negative effect on the sharpness or the needles. I assume that dry heat sterilization would have a similar effect on the edge of a straight razor. :shrug:

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Originally Posted by Russel Baldridge

But why do you need to autoclave your razors?

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Because I want to use a traditional straight in a barber shop, instead of a disposable-blade, shavette-type razor.

Why not dip them in 70 or 100% industral ethanol?

Endoscopes for instance are sterilized at much lower temperature as 200 degrees would destroy the rubber like lining. They are put in special washing machines using a certain antiseptic liquid. I think that would be better for your straights. Do you intend to use carbon or stainless steel razors?

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Originally Posted by Kees

Why not dip them in 70 or 100% industral ethanol?

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Because the law in his country says they have to be autoclaved. :shrug:

But dry heat transfer is a lot worse than wet heat transfer, so that is probably where the increased temperature comes from.
The temperature is awfully close to tempering level, so it's possible that repeated cycling will deteriorate the steel temper.

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Originally Posted by Kees

Why not dip them in 70 or 100% industral ethanol?
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Do you intend to use carbon or stainless steel razors?

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As Bruno said, because the law requires it. As for carbon versus stainless steel, what's the difference?

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Originally Posted by Chimensch

As Bruno said, because the law requires it. As for carbon versus stainless steel, what's the difference?

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I think oxidation 'could' be an issue with carbon steel. For stainless it wouldn't matter.
But if you didn't want to get a wet autoclave because of the price, the point is moot.

Oxidation is an issue with carbon steel in a steam autoclave. Dipping the needles in a rust preventative prior to bagged sterilization was the solution to the problem.

To kill the bugs the material MUST be sterilized at 265 Fahrenheit or more.

It depends on the steel, of course, but in general a heat treat to 473 °F or 245 °C for any period of time will probably decrease the hardness very slightly. Meaning a Rockwell C hardness of 58 instead of 60 or 62. No big deal. As Russel Baldridge pointed out, Rc of 52 or something can be used for shaving. It might actually be easier to hone and stop, if it lasts perhaps marginally less long. (For what it's worth my dad was a metallurgist witha PhD, none of which transferred to me.)

I say that if that's what the law requires, do it, and see what differences you notice, and let us hear about your experiences!

Matt

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Originally Posted by Chimensch

Because I want to use a traditional straight in a barber shop, instead of a disposable-blade, shavette-type razor.

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Just a cautionary note, old chap - disregarding all this stuff about disinfection (I'd just use barbicide and hooey to the autoclave - totally unnecessary) - do you have enough insurance? A nick with a shavette is one thing - make a slip with a straight and oooooooooooooo my god :eek::eek::eek::eek::eek::eek: do take care! Lawsuits are expensive............:(

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Originally Posted by blueprinciple

Just a cautionary note, old chap - disregarding all this stuff about disinfection (I'd just use barbicide and hooey to the autoclave - totally unnecessary) - do you have enough insurance? A nick with a shavette is one thing - make a slip with a straight and oooooooooooooo my god :eek::eek::eek::eek::eek::eek: do take care! Lawsuits are expensive............:(

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I appreciate your point of view ... but there are other considerations. Italy is a very bureaucratic country. Once you get on some agency's list, it never goes away. Then there's the fact that it isn't my shop and that I have a regular job and this will just be a hobby. I can't go into a friend's shop and risk bringing down the health inspectors on him when its his livelihood that's at risk. In fact, my barber offered to take me as an apprentice and train me but I decided to go to school first because I want to do it right. Not that he does it wrong, but he could easily overlook something that is obvious to him but foreign to me. Besides, I'm not much of a risk taker and, if my ducks aren't in a row I'll be so nervous that I'll be sure to slash the very first customer.

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Originally Posted by blueprinciple

Just a cautionary note, old chap - disregarding all this stuff about disinfection (I'd just use barbicide and hooey to the autoclave - totally unnecessary) - do you have enough insurance? A nick with a shavette is one thing - make a slip with a straight and oooooooooooooo my god

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:thinking:

Disposable blades are much more likely to nick than regular straights, and while regular straights may give smoother shaves, disposable blades are sharper in the 'like a hot knife through butter' sharpness sense.

If I had to shave someone I'd choose a real straight over a disposable for that alone.
Real straights are certainly no more dangerous than disposable (the opposite I'd say).