Etching Sword Blades to Remove Rust

How to restore antique arms & repair practice swords.

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bond_fan
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Etching Sword Blades to Remove Rust

Post by bond_fan » Thu Dec 04, 2008 6:23 pm

It was suggested to me that if a blade isn't too rusty and not pitted that instead of a full polish one could etch the blade using an acidic solution to remove the superficial rust and bring out the grain in the folded metal.

I was wondering what type of solution one would use, the steps to safely remove the rust and protect the blade afterward without removing the patina from the tang and to properly dispose of the used solution?

Thanks!

Nik
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Post by Nik » Tue Dec 09, 2008 8:20 am

Since none answers, at least the following advice: be VERY careful with using industrial rust solver, it's inflammable, explosive, and a breathing poison. You can only use it in well ventilated areas, and with an industrial breathing mask used by professional car laquering workers.

Regarding etching, I only heard that the acid can sink into the fine hairlines between the steel layers and continue rusting the blade. You need to make sure to use only a very soft acid and not a potent one. You probably need at least to inactivate it using a soft basic solution afterwards. Try half a dishwasher tab solved in a large enough amount of water (litre), and test the solution on the blade near the handle if it leaves marks. This solution should be applied on the blade after removing the rust with low grade acid (you will definetly need to manually rub the points off with a bit of force), and afterwards cleaning that off with enough of water. Then you need to dry it completely, using a hairdryer, and protect it with weapon oil. You should test that procedure with some carbon steel knife first, and not on your $6000 sanmei original.

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Graham Cave
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Post by Graham Cave » Tue Dec 09, 2008 11:26 am

A corrosion remover used by museums and conservation professionals is Renaissance Metal De-Corroder.

If you don't want to protect the steel with an oil, then an alternative would be Renaissance wax. This has virtually no odour.

Another useful conservation product is Vulpex Liquid Soap. This is a degreasant which can be diluted with either water or white spirit .

Nik
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Post by Nik » Tue Dec 09, 2008 12:40 pm

This is what I meant, a low potency aminoacid that will slowly convert rust into someting that can be rubbed off, while not being aggressive enough to work on the pure metal. Good buy. Plus, judging by the description, you don't even need to deactivate it using a basic solution. Easier to use.

Philip Tom
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"isn't too rusty and not pitted"

Post by Philip Tom » Wed Dec 10, 2008 9:55 pm

Rust (oxydation) tends to form pits, or at least roughen, the surfaces of ferrous objects. Iron is converted to iron oxide, and detaches from the surface in the form of a powdery substance or actual flakes, depending on the severity of the condition. The pits may not be deep enough to feel with fingertips, but under magnification, they can be seen.

The use of chemicals to remove active rust (and thus halt the advance of corrosion) does have its hazards, as Nik has pointed out. Neutralization after use is essential.

Aesthetically, the result can leave much to be desired, since if all the oxydation is removed, you get craters in naked steel, or a rough frosty look which can be unsightly. Also, you can't rely on acids acting on a rough, rusted surface to bring out much in the way of metallurgical details, unless the layering is of an extremely coarse and crude nature. This is because the residual roughness interferes with the reflection and refraction of light from the surface, which is what enables us to see the details with naked eyes, or through lenses. Only a proper polish can prepare the surface, to the requisite smoothness, so that the metal structure can be revealed.

In some Oriental cultures, the degree of polish on things such as swords and bronze mirrors goes beyond functional parameters, it also symbolizes the purity and clarity of the superior man's soul. This being said, it's no wonder why the three sacred National Treasures (Kokuho) of Japan consist of polished objects : mirror, sword, and jewel.
Phil

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