Three Rusty Tsuba

[JohnTo]

Opinions amongst tsuba collectors differ as to how to treat rusty iron tsuba, as often illustrated on the NMB over the years, so I thought that I would submit my treatment of three rusty tsuba in my collection to open some debate.  Have I restored them or wrecked them?  The three tsuba came in a mixed lot of five at a local auction; the other two, being cast (nanban and Akasaka copy) were free of rust.  As they were cheap, grimy and rusty I bought them as a restoration project.

Tsuba #1 was in relatively good condition with just a few areas of red rust.  It was also signed Yamashiro Kuni Fushimi ju Kaneie; the main reason for buying the lot.  The only treatment that I have given this tsuba is to wipe off the red rust using cotton buds soaked in WD-40 and then to place the tsuba on a radiator to drive off the oil residues. Personally, I like WD-40 as it is a modern product developed for the aircraft industry and scientifically designed to penetrate rust.   I know that many collectors like to use the traditional chogi oil but I note that the Japanese dealer Aoi Art no longer uses this on blades as they consider that it promotes staining and now use high quality machine oil.   I do think that the treatment may have darkened the brown patina, but can’t be sure and I’m pleased with the result as no rust has reappeared on the tsuba in more than a year.
 

Tsuba #2 is an aoi-gata tsuba, probably for a tachi, but I’ve taken the photos katana style.  This tsuba was pretty grubby and has only been given the WD-40 treatment together with a clean of the inome bori (boars eyes) piercings with a dental hygiene brush, again soaked in WD-40.  The iron has definitely taken on a darker colouration after placing on a radiator, but whether this is due to the WD-40 or just the removal of the surface dirt I can’t say.  There are shiny black patches on the tsuba and I’m not sure if this is the original patina or remnants of a lacquer coating.  At this point I’ve stopped any further treatment and the tsuba has remained rust free for the last year.  Any suggestions for further action?
You may notice ‘white rainbows’ above the middle of the tsuba, these are just lighting artefacts caused by taking the photos on a windowsill, sorry.

I've posted tusba #3 separately below so the postings don't get too big
Regards, John
(just a guy making observations, asking questions, trying to learn)
Photos
1: Kaneie original omote
2: Kaneie original ura
3: Kaneie omote after WD-40
4: Kaneie ura after WD-40
5: Aoi-gata original omote
6: Aoi-gata original ura
7: Aoi-gata omote after WD-40
8: Aoi-gata ura after WD-40
 

[JohnTo]

Tsuba #3 was more of a challenge and I have posted this separately below for clarity with the photos.
Tsuba #3 is essentially a round, flat iron plate with a slightly raised engraved Chinese landscape scene with a few small pieces of copper and silver inlay highlights and some crisscross gold nunome (see pics).  It was also covered in red rust, so the first treatment was to clean half of each side with cotton buds and WD-40.  A lot of loose red rust came off on the cotton buds and the surface darkened with the WD-40.  I gave the tsuba several more cotton bud/WD-40 treatments (see pics).  At this point it became evident that the tsuba was either never patinated, or more likely, a previous owner had tried to remove the rust with acid causing the bare metal to be exposed and become more susceptible to rusting.  Trying to remove the thicker black rust with a piece of bone and WD-40 was slow and relatively unproductive (rust did come off, as evident from cotton bud swabs).
It was at this point I decided to give Renaisance Metal De-Corroder a go (many of you will probably be familiar with Renaissance wax used in museums).  De-Corroder is an amine complex of hydro-oxycarboxylic acid in an aqueous solution with a pH of approximately 4.0 (slightly acidic).  It claims to ‘selectively rupture the bond between base metal and corrosion layer, reducing rust to sludge which is easily wiped or brushed away.’  The instructions talk about immersing the object but, as the bottle contained just 100 ml, I applied the solution to a couple of badly rusted areas with cotton wool wrapped around a wooden cocktail stick, placed the tsuba in a plastic CD jewel case (to prevent drying out) and left it overnight.  The next morning there were two patches of black gel on the tsuba which I washed off with water and a cotton bud to reveal most of the rust had gone, revealing bare metal (see pics).  Note:  I always use rain water rather than tap water to wash iron tsuba as I don’t want dissolved salt residues getting into open pores in the iron and catalysing further rusting.
Encouraged by these results I applied about another five treatments over the entire tsuba, including the mimi, nakago ana and hitsu ana (see later).  Between applications the gunge was washed off (water, cotton wool buds and electric toothbrush) and the engraved areas scraped out with wooden toothpicks before drying overnight on a radiator.  After that no further improvement seemed evident, the remaining stubborn black spots (see pics) did not seem to go and I considered these as being ‘patina’ rather than ‘rust’ thus preventing the De-Corroder from penetrating.  I was left with an essentially bare iron tsuba with copper, gold and silver(?) inlay still intact and shiny.
Next stage was to patinate the iron and I decided that a deep brown rather than black patina would be most appropriate based upon the Kaneie tsuba in part I and Choshu Chinese landscape tsuba in my collection.  For this I used Birchwood Casey Plum Brown Barrel Finish, intended for restoring muzzleloading guns.  This should be applied at 130°C and to do this I placed the tsuba on a gas BBQ grill and wiped the solution on the hot tsuba with some of my wife’s cotton makeup pads and cotton buds (for the nakago and hitsu ana).  After about 5 applications I had achieved a rather muddy looking and powdery finish, much to my disappointment.  WD-40 improved the surface somewhat and removed loose patina and then I used a wax from a church bell foundry, which finally gave an acceptable finish. At this point I stopped.
Initially I did not attempt to remove the rust from the nakago and hitsu ana, just as the previous owner had neglected to do (in accordance with Jim Gilbert’s advice).  However, I could see little point in leaving this thick layer of rust so this was also given several treatments with De-corroder and revealed something quite unexpected; alternating bands of bare metal and dark rust (see photos).  These striations went around the entire surfaces of the nakago and hitsu ana and I estimated there were about 10 light/dark bands across the thickness of the tsuba.  The iron had been forge folded at least 3 or 4 times (8-16 layers) before making the tsuba and was not just a plain old piece of homogenous iron as I had assumed!  My admiration for the artist leapt at this point.  I also felt that this explained the 1 cm square patch on the surface of the ji next to the hitsu ana.  It was where the rust had tunnelled between the layers and lifted the thin iron surface layer away from the ji (see pic).  I did consider polishing out this patch and maybe polishing out the rust pits in the mimi with fine emery cloth and abrasive powders, but decided that this is where I should stop. 
In conclusion, I considered tsuba 2 and 3 to be beyond commercial restoration by a professional and my main aim was to remove areas of active rust and prevent further corrosion.  Also to experiment, learn and have a bit of fun.  I was particularly impressed with the action of De-Corroder on iron as it seemed to act as claimed, namely softening up rust while leaving the base metal unchanged.  Red and black rust are essentially the same iron oxides as the patina found on iron, however patinas are tightly bound fine oxide particles which prevent further corrosion.  De-Corroder does not seem to easily remove the patina rust from iron, but I have not dared tried test this hypothesis on a rust spot on an iron tsuba with an otherwise intact patination.  So beware, I am not advocating its use on all tsuba!
Have I rescued or wrecked these tsuba?  I’ll let the NMB jury decide. 
Best regards John
(just a guy making observations, asking questions, trying to learn)
Photos
1: Omote as bought, with kogai hitsu ana on left rather than right side.
2: Ura as bought
3: Omote after several WD-40 cleans and bone abrasion
4: Ura after several WD-40 cleans and bone abrasion
5: Ura with two initial areas covered with de-Corroder after standing overnight.
6: Ura after De-Corroder washed off.
7: Omote after 5/6 treatments of De-Corroder showing residual dark spots of patina/rust.
8: Ura after 5/6 treatments of De-Corroder showing residual dark spots of patina/rust.
9: Omote after patination
10: Ura after patination
11: Folded layers of iron exposed in nakago and hitsu ana (side 1)
12: Folded layers of iron exposed in nakago and hitsu ana (side 2)
13: Area on Ura believed to be due to loss of a single layer of forged iron

[Dan tsuba]

Wow John,

 

Great job on all the tsuba! 

 

I have only been collecting tsuba for a little over 4 years.  I can only afford the “less expensive” tsuba out there.  So, almost all of my tsuba are received with rust on them. The only thing I do is take some “gun bore cleaner” and clean off the tsuba with a toothbrush dipped in the bore cleaner.  Then I wipe off the tsuba with a clean rag.  This takes off some of the rust and darkens the tsuba slightly.

 

Sometimes if there is extra “gunk” in the tsuba I will dip it in mineral spirits.  That takes off any extra dirt that may have accumulated on the tsuba.

Then (when I am done cleaning it to my satisfaction) I dip the tsuba in a small container that has mineral oil in it.  Then I place it on a rag and let it dry overnight.  I do that so that there is a  “coat” of oil on the tsuba to prevent further rusting.

 

I have done that with all of my tsuba (about 100 of them!) and there is no further rusting occuring on any of them.

 

Also, I do not take any “horn” material to the tsuba to take off the rust any further.

 

I have also  learned from a previous thread on the forum that by taking a “horsehair” brush every day (like a shoe brush”) to the tsuba, that over time (like 6 months to a year!) the tsuba will appear in a much better condition!

 

I have done this with a couple of my tsuba, and it works!

 

With respect,

Dan