Restoring a Plane Blade

[Christian_C]

Hi,

I want to know how one would go about restoring the black skin finish on a Japanese plane blade. I've heard of hot black oxide finishing but it sounds very dangerous, and cold black oxide finishing provides mediocre results that lead to the black rubbing off on skin and clothes. What is the process that the Japanese blacksmiths use? If it is much to technical to be performed by an amateur, is there an alternative that provides comparable results?

Thanks to all those who read this and much thanks to those who respond.

Christian Castillo

[NeilS]

Hi Christian

Not sure why you want to restore the black oxide finish?

If it's for aesthetic reasons, others may be able to give you advice on how to restore the black oxide finish.

If, however, it's to get the protective function of black oxide then I suggest you simply apply Camellia oil regularly to your blades to resist corrosion. Over time they will develop a grey patina. If necessary, remove any existing corrosion in an electrolysis bath.

All of my very old Japanese blades have that gunmetal patina typical of old and well used tools. To my eye that oily grey look is as aesthetically appealing as the new black finish.

Neil

[yojimbo]

I'd certainly like to know for aesthetic reasons.

And yes, camillia oil is wonderful.

[Sheets]

The original black oxide is produced when the tool is heated to harden the edge. You can't really restore the "black" colour as original without re-heating/hardening the tool which would not be advisable. As you mentioned, there are various ways to chemically create a black finish, but I don't know how well any of these ways work (never tried any) and from what I've read (maybe same sources as you) the results don't seem as durable and present other difficulties.

I prefer the the colour of rusty oxide myself and a good thing too, since most of my tools seem to get that way:B

Steve

p.s.,
Actually, I do like the brown colour from old rust. Keep it oiled and it gets darker and the rust doesn't progress.

[Christian_C]

My primary reason is aesthetic, although the corrosion protection is nice as well. None the less, I do make it a habit of oiling my tools after every use rendering the corrosion protection reason null. Guess I'll settle for the gray patina. Thanks for response. If anyone does happen to know though, it would still be great to find out.