Rust Removal
Isaac’s comment on my anvil’s rust issue reminded me that I had a set of “Engineering Workshop Practice” by Arthur Judge on my bookshelf.
From last reading I remembered that volume iii had a chapter on “Miscellaneous Workshop Hints and Recipes”.
Here’s what he has to say on rust:
Rust-removal Methods
Rust may be removed from iron and steel parts by two different methods, viz. (1) the use of abrasives, and (2) the use of chemicals.The abrasives used with the first method include carborundum and emery powders, pumice, tripoli, and rottenstone. They are applied dry, or mixed with lubricating oil , turpentine, or paraffin oil, using a piece of cork, felt, or cloth to hold the mixture. For very small steel parts, ordinary ink eraser cut to a suitable shape will be found effective for removing rust.
A paste made from carborundum or emery powder mixed with olive-oil applied with a thick piece of cloth or felt, is useful for removal of heavy rust deposits.
If rusty steel parts are immersed in turpentine, naphtha, or paraffin oil for about 12 hours, they can readily be cleaned with emery cloth or one of the abrasive mixtures previously mentioned.
A good chemical method is to immerse in a hot strong bath of caustic potash for about 30 minutes. Then immerse in a cold muriatic-acid pickling bath; in a few minutes all of the rust will be removed or loosened sufficiently to be rubbed off readily with a cloth.
Another satisfactory method for steel tools is as follows: Dissolve, gradually, in one quart of distilled water sufficient chloride of tin to make a saturated solution, i.e. until the water will not dissolve any more of this salt. Put the tools in a jar containing this solution and leave for about 10-15 hours. Then remove then from the solution and, after rinsing in hot water, dry with a cloth.
Metal sculpture in brass, mounted on an 1800s French Coin
sounds good. Can you supply the chemicals?
I found suppliers for the carborundum powders online.
The caustic potash and muriatic acid might be a bit of a problem and not particularly safe.
Chloride of tin is also a challenge as there is apparently different forms of it.
However I have found some chemicals from HG that do a good job, more on that later in the week.