Rust inside fittings

[O koumori]

Is there a 'safe' way to arrest or remove rust on the inside of Iron fuchi / kashira?

Thanks,

Dan K

[ROKUJURO]

Dan,

if it were my own iron TOSOGU, I would work on them first with pointed pieces of antler, ivory, bone, or bamboo until the corrosion is almost eliminated. Then I would try to prevent further rust with oil or - in critical cases - even with a rust converter (inside the items!). 

But that would be my personal go, professionals might have other ideas, perhaps working with URUSHI.

[O koumori]

Thanks Jean,

I am trying the bamboo; I can at least shape it and it's too small to get in there with anything else!

Dan K

[JohnTo]

Hi Dan,

I have been experimenting with Renaissance Metal De-Corroder on a badly rusted tsuba.  This is an amine complex of hydro-oxycarboxilic acid in water at a pH of 4.0.  It claims, and my observations agree, that it ruptures the bond between rust and iron without having any significant effect on the sound metal.  Easier than picking away with bamboo or bone.  Leave on overnight and wash off with water using a dental brush or Q-tip to remove the softened rust.  As you are talking about the INSIDE of a fuch/kashira I assume that you are not worried about damage to the patina.  I cannot guarantee that this product will not harm the patina.  The tsuba that I have been working on had evidently been 'cleaned' by a previous owner with acid and the patina lost before the tsuba was put aside and allowed to rust again.  Long before I got it as part of a job lot.  I am I the process of writing up my experiments for discussion/criticism on the NMB.

As I indicated, if preservation of the patina is important then this may not be the appropriate treatment as patina is just a type of rust.  I have been looking through my collection to find a cheapo/poor quality iron tsuba with a rust scab to see if the scab can be removed without damage to the surrounding patina but have not found a candidate yet.

Best regards, John   

[Brian]

I expect it's similar to Evaporust. Be careful. It removes rust very well, but will strip just about any patina of anything else.
I don't recommend it for anything Japanese sword related. Bare bright pitted metal sometimes looks worse that black rusted matal.

[O koumori]

Gentlemen,

Thanks for the ideas and advice. 

I can 'play around' on some junk metal before trying anything on anu tosogu.

Best,

Dan

[Spartancrest]

7 hours ago, O koumori said:

anu tosogu.

Do you mean 'UBU' tosogu? 

[JohnTo]

I don't think that DeCorroder and Evaporust are similar.  Evaporust seem a bit cagey about their ingredients, just vague mentions of chelating agents Quote '  The Selective-Chelator is not strong enough to remove Iron-to-Iron bonds from un-corroded steel and does not harm the underlying metal.  The Chelator is too expensive to use large quantities in the finished product.  An organic chemical that easily loses sulfur to form ferric sulfate was added to remove iron from the Iron-Chelator complex.  This allows the Chelator to remove more Iron from Iron Oxide.  The sulfur-bearing compound is much less expensive than the Chelator and makes Evapo-Rust™ economical to use. Evapo-Rust™ has a chemical carrying capacity of 300grams of pure, dry rust per 5 litres.'

De-Corroder is much more expensive £10 for 100 ml, Evaporust £20 for 1000 ml.

 

regards, John

[O koumori]

13 hours ago, Spartancrest said:

Do you mean 'UBU' tosogu? 

Meant "any"

I know how to spell, but my fingers sometimes don't...