Thread: 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.

Originally Posted by Russel Baldridge

But why do you need to autoclave your razors?

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?

Originally Posted by Kees

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

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

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.

Originally Posted by Kees

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

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