Mastro Livi technique

I just finished watching avideo by Mastro Livi making a razor from start to finish.
I have some questions.

1. When he completed the rough grind and said he is going to temper,
After removing the blade from the forge he only quenched the edge of it for a second or two then submerged the complete razor.

2. He never baked the blade, just dipped it in the quench oil and burned it off in the forge 3 times.

NOTE: The steel being used was RWL-34

This is the video and the tempering is at 27:40 thru 30:15 on time.

https://www.youtube.com/watch?v=d6DJedrjeK4#t=1864

Basically, what he is doing is letting some of the heat in the spine flow back into the edge. This is called auto tempering. You have to be pretty quick to do it. What you do is quench the edge, pull it out, and watch the color of the edge section. It will turn from grey to straw (and if you wait too long, blue and purple and then colorless again) at which point you quench the rest. This way the blade is already partially tempered.

Then the dipping in oil and burning it off: this is another way to temper. The oil will burn off at a certain temperature, which is more or less stable for a short while, while the oil is burning off. This takes care of the rest of the temper.

As I mentioned, this is called auto tempering. It has pros and cons. It is much faster than oven tempering. The downside is it can be error prone, and on larger pieces it is more difficult to control. Now, if you fail, the temper is ruined and you have to start over. But that is not a real drama. The main reason he is doing it, is simply time I guess. This way he doesn't have to wait for a long time in the tempering oven. It has no special benefits in terms of metallurgy that I know of.

I'm such a method of tempering chisels, only when I do turn off the light quenching. Mastro Livi have a lot of experience, so he knows better. Bruno everything is explained in detail.

In one of his videos he shows a box of RSOs with cracked blades and missed tempers, I'd rather use an oven even if it was a toaster oven.

For chisels I have auto tempered.

Mastro Livi likely does it that way because that is how he learned to do it and he has been doing it long enough that he gets it perfectly right most of the time. Same thing with the really experienced traditional Japanese smiths. I like to joke that they make outstanding knives IN SPITE of their old school methods. I would not dare to try to do things that way because I am sure that I would end up with a pile of busted up knife and razor shaped objects. :p

I say, just experience. I personally work differently.

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Originally Posted by Gipson

I say, just experience. I personally work differently.

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The best answer to the question of "how does he do that" may " he is Mastro Livi and we aren't." Same answer as to how Bill Moran, William Scagel and Frank Richtig used to do stuff. :)

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Originally Posted by JDM61

Mastro Livi likely does it that way because that is how he learned to do it and he has been doing it long enough that he gets it perfectly right most of the time. Same thing with the really experienced traditional Japanese smiths. I like to joke that they make outstanding knives IN SPITE of their old school methods. I would not dare to try to do things that way because I am sure that I would end up with a pile of busted up knife and razor shaped objects. :p

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So, if I am just starting out and LEARN to do it this way, eventually I may be saving time?

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Originally Posted by paco

So, if I am just starting out and LEARN to do it this way, eventually I may be saving time?

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Not in the way you are thinking of.
Auto tempering is something that is convenient if you are working in a production line process where throughput matters. However, it doesn't necessarily save you time per razor. After quenching, I temper my stuff by tossing it in the oven for an hour or 2. That doesn't cost me any time either, since that is what I do at the end of my working day. That way my razors are tempered in a foolproof manner and they are redy the second I want to do something with them.

Additionally, auto tempering is not always possible, since large blades and complex shapes are much more difficult to control.

Also, people like to fawn over names of the experts, but they're just people like you and me. They don't have magical abilities that us mortals are lacking. Noone in that list of names is doing anything that we can't do. That said, if you are just starting out, it is beneficial to do things in a manner that is easily repeatable and easy to analyse. That way you get consistent results, and you have a frame of reference for when you start to experiment with your processes.

Metal must feel, I do not know how to explain it. Starting work on the anvil and finishing heat treatment. If there are errors then you can see them, but the error - it is a razor that must be thrown out. Errors occur in all masters, but rarely.

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Originally Posted by Bruno

Not in the way you are thinking of.
Auto tempering is something that is convenient if you are working in a production line process where throughput matters. However, it doesn't necessarily save you time per razor. After quenching, I temper my stuff by tossing it in the oven for an hour or 2. That doesn't cost me any time either, since that is what I do at the end of my working day. That way my razors are tempered in a foolproof manner and they are redy the second I want to do something with them.

Additionally, auto tempering is not always possible, since large blades and complex shapes are much more difficult to control.

Also, people like to fawn over names of the experts, but they're just people like you and me. They don't have magical abilities that us mortals are lacking. Noone in that list of names is doing anything that we can't do. That said, if you are just starting out, it is beneficial to do things in a manner that is easily repeatable and easy to analyse. That way you get consistent results, and you have a frame of reference for when you start to experiment with your processes.

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Bruno: Thank you for this input. Very helpful explanation. Thanks again!

If I tried this method and do not succeed have I ruined the razor or can I reheat, quench, and oven temper?

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Originally Posted by paco

If I tried this method and do not succeed have I ruined the razor or can I reheat, quench, and oven temper?

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Generally yes, if you blow the temper you can just do it all over.
That is why I prefer oil hardening steels. They tend to have no risk of warp or breaking, so the risk of having to do it all over are absolutely minimal.
Water quenching is always riskier, and therefore doing it over increases your chances of destroying the blade.

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Originally Posted by paco

If I tried this method and do not succeed have I ruined the razor or can I reheat, quench, and oven temper?

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As long as you have not done your finish grinding you can re heat treat. Trouble is, it can be difficult to ascertain a missed temper without actually honing the edge IMO.