What Shibuichi Looked Like When It Was New.

[peterd]

I have three shibuichi tsuba and they are all very dark, see pictures. One of the tsuba must have been mounted as it shows more of the original colour on the seppa-dai. I like them as they are but I'm not sure whether or not they may look better restored to their original colour. I'll have to spend some time considering whether this is something I should look into having done.

 

I was wondering, how long does the restored finish last before the colour becomes darkened again? 10 years or 100 years etc.? Any idea?

[peterd]

I also have a tsuba that I am hoping Ford will professionally clean and restore. I would like it to look like it did originally but it has an age patina some may think desirable and so a lighter clean could be the way to go. Opinions please.

[Heringsdorf]

Peterd,

 

Once the original patina is restored it will last close to 100 years. Since there is less Sulphur in the air today then back then, it will last quite long until the Shibuichi will darken again.

[docliss]

Ford, a very simple question ... Sentoku can patinate to a wide variety of colours, from a very pale to an olive brown. Does this coloration depend upon the constituents of the alloy, or upon your method of patination? In other words, do you personally select the coloration that will result from your repatination and, if so, how do you decide?

 

With kind regards, John L.

[Ford Hallam]

Hello John

 

That's not a simple question at all :-)

 

Firstly, we need to establish whether or not the metal you are refering to is a sentoku alloy. The consensus seems to be that this would be a zinc:tin intermediate brass/bronze.

 

The only maker who does us a favour by actually inscribing his work as being of sentoku-do is Mitsuhiro. He of the 1000's monkeys. But analysis shows his alloy to contain no tin. It's actually a brass.

 

As for the rest, I'm not sure we can call something sentoku merely on the basis of the patina colour.

 

Having said that, as with shibuichi the patina is largly dependant on the actual alloy composition. One confounding issue is that of surface deterioration where the more volatile elements in the alloy have oxidised out leaving a copper rich surface. In this case the patina will be quite different to that which the fresh metal would have produced. This is why careful examination of the metal surface is essential in deciding what degree of re-polish or resurfacing is appropriate.

 

As for my own approach with the bronze, brass, sentoku alloys where possible I leave what patina is intact well alone and merely work the bare metal to that. Or, where the patina can't be saved I make a note photographically of any traces of the original patina to serve as a confirmation that my results are appropriate.

[docliss]

Thank you Ford for that detailed explanation. The more we read your posts the more impressed we become with your achievements! John L.

[Ford Hallam]

Thats very kind John, Thank you.