Verdigris Problems on ko-kinko wave tsuba

[Zantetsuken]

Hi everyone,

 

I got a new Tsuba. In hand I recognized old wax on the surface. I gently removed it with mineral spirits. Now the full extent of verdigris is visible. Immediately after laying it in a jar with mineral spirits, the wax, some dirt and verdigris particles were removed and the liquid turned grey-greenish. The wax wasn’t coloured, but still camouflaged the now fully visible extent of verdigris. I already have experience with removing verdigris under the microscope with horn/bamboo tools, but it’s very time consuming. In this case, there will still be patina problems / abraded areas after removing the verdigris.

Is professional repatination economically wise or should I just remove some / all of the verdigris and rewax it with renaissance wax?

Thanks a lot,

Simon

 

 

[Zantetsuken]

First two hours of work done. Lightning condition is slightly different, very hard to make reliable before and after pictures. It definitely looks better now. I attacked many areas moderately and didn’t focus to perfectly remove zone after zone. In some places the corrosion compromised the underlying metals and caused light scaring / pitting. 
 

stuff used:

- binocular microscope 20x magnification 
-fresh bamboo toothpicks and carved pieces from fresh bamboo chopsticks (those are softer and have a lower mohs hardness compared to older, long dried and higher quality bamboo)

-new baby tooth brush and neutral soap (only with medical quality distilled water to prevent lime build-up). This removes the residue composed of verdigris and abraded bamboo particles

-99,9% ethanol for rinsing

-Mineral spirits for a final bath to remove further traces of wax particles that were loosened while cleaning.

 

Still a lot of work to do, probably 10-15 hours.

[Bugyotsuji]

Great work, Simon, looking a lot better already.

 

Everyone was giving you like signs, but waiting to see who would enlighten us first! 

[Zantetsuken]

Thanks, Piers!

I will post further progress here and also tools I‘ll use. I have pretty much experience in restoring wood and iron antiques, but not so much on soft metals yet. 
the verdigris must urgently be addressed. It looks like the wax trapped some moisture and it got worse. The longer it sits, the more scaring and pitting occurs. I‘ll store it especially dry while working on it. 
I‘m always happy for further advice to refine my procedure.

[Matsunoki]

I have used this product in the past on both bronze and copper with some amazing results. Great patience and care is needed…..all the usual toothpicks etc etc.  I used to place items in a bath of it to start with and then work slowly. Haven’t used it lately (it went out of production but is back now) but from memory it also leaves a protective coating.

https://verdi.care/?srsltid=AfmBOopfmM98iXEsjHu4UW_hFPrZ4Jq44pagEBJpCCIZjs6uU-FWXg5q

[ROKUJURO]

Avoiding grease or fatty substances on copper alloys will help prevent green corrosion.

[Zantetsuken]

Thanks for the link to this product. The  liquid seems to strip off quite a bit. Personally I prefer a cleaned only look. My tsuba is about 400+ years old and I don’t know the chemical composition, so definitely a mechanical only cleaning. Shakudo patina seems to be incredibly thin and prone to chemical reactions (sweat, sulphur, acids, sebum etc.). After using chemicals, i‘d need a full repolish and repatination with rokusho. Still not sure this is economically wise. This will probably cost more than the tsuba is valued at.
I also discovered the „silver balls“ to be of lead and not silver. Not sure how lead reacts. To many variables for me to use something like this.

[Bugyotsuji]

With Shakudo tsuba many people in Japan recommend wearing soft cotton gloves, i.e. no bare hands.

[Matsunoki]

1 hour ago, Zantetsuken said:

The  liquid seems to strip off quite a bit.

That depends on how you use it and how vigorous you are….it isn’t harsh. 

[Franco]

Insight, a professional restorer would use both mechanical and chemical treatments depending upon what is found. This, in order to ensure the surface is stripped absolutely clean. Otherwise, there could be failure in the re-patination process resulting in an ununiformed finish. One shakudo tsuba I had professionally restored took five (tedious, careful, time consuming) mechanical cleanings before being chemically prepared for re-patination.

 

Even then the success of the re-patination will depend upon the quality of the shakudo. Which to some extent will be an unknown factor.  Eventually, the quality of the shakudo will become apparent in the final result. On an excellent shakudo tsuba the finish will continue to re-patinate and improve, even dramatically, over time. 

 

With this wave tsuba, not only is there the body to restore but the rim needs attention, too. Then there is the question of what to do about all of the silver? and/or gold? drops that are missing?

 

Value? Worth restoring? Kantei gives an answer. 

 

Good luck.

[Curran]

Interesting thread.

I fear verdigris on copper or shakudo  >much more> than I fear rust on iron tsuba .  [That partially depends on the school's iron and time in history. Some schools, if they get rust... it is a long long time to heal them.]

 

Sometimes verdigris does a real doozy on otherwise very good ko-kinko tsuba.

Ford H. and others gave good advice on verdigris.

I'm glad to see someone sharing their struggle with chemistry and copper based tsuba.

 

 

[cluckdaddy76]

I have used EVOO with a Q-Tip as someone suggested this to me and it worked perfectly on my kinko tsuba to get rid of the verdigris.

 

Jason