Join Date: Dec 2017
Re: Vinegar, C6H8O7, NaCl and H2O2.
For what little it may be worth, I've done a few rust removal experiments on planer blades (from lumber mills), neglected and abused Mora knives of laminated steel construction, "load binders", and hard-to-come-by threaded fasteners using either undiluted acetic acid from Canadian or Filipino producers, undiluted Peruvian lemon juice, or an ad hoc mixture of both. For blades, I'll wrap in paper towel, apply liquid to saturate, then wrap in common, food grade plastic wrap or a similar shipping grade product. The result after unwrapping 12-96 hours later is always a strong odour which I'd describe as mouth-watering in a Limburger cheese sort of way. Provided that care has been taken to remove all oil and/or grease from the steel treated in such a way, in most cases, the rust will have disappeared, and the steel will be quite black, and vigorous rubbing with nothing more abrasive than a paper towel or a stick of (soft, not hard) softwood is needed to remove this blackening completely. Faster results might possibly be achieved using a toothbrush, perhaps in combination with toothpaste. This last mentioned method works on silver plate and coinage (though I'd discourage it), but I've never tried it on steel.
I've read of a method used at one time in Japan to cause a durable layer of glossy, black protective oxide to form on chisels and axe heads by first soaking in a solution of water and kosher salt until fully coated in rust, and then boiling the rusty tool in hydrogen peroxide to bring about the conversion of the rust to the protective black oxide. I've yet to try this method, but have considered it for "gardening-variety" machete, parang and golok, and as a possible alternative to traditional warangan treatment for keris due to arsenic being unavailable where I'm living. If anyone has any knowledge of this method, any input would be appreciated.