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| rebelrider.mike:
In addition to the rust, I found a thin layer of dull gray coating on the sheets. Some of the sheets were relatively intact, but most were in pretty bad shape, with the coating peeling off and I felt that a new insulative coating on a clean surface would be best. Perhaps this was a mistake, but what's done is done. If I can't fit all the sheets back in, I'll have to compensate by reducing the area of the core in the calculation. So the number of turns needed may increase. Better that than to not have adequate insulation between the sheets. Sounds like an oxide is the way to go. Black oxide tends to be thinner, tougher, and more stable than the other iron oxides. It's also less permeable to oxygen and so protects the metal better from future oxidation. I'll look into the best way to produce a good oxide layer on the sheets. Hot distilled vinegar comes to mind. I've never actually tried it before, so I've got some reading to do. |
| GeorgeOfTheJungle:
Yep, clean them well with diluted muriatic/hydrochloric acid, and it will take no more than half an hour outside under the sun to have them coated in an even, beautiful rust. A steam cleaner may work quite well too. |
| Ian.M:
Hot vinegar is usually used to strip blueing and other oxide coatings. DIY zinc Parkerising in phosphoric acid solution 'loaded' with some zinc, is probably the easiest option, or you could flash rust them as George suggests then boil them in water to convert the rust to black oxide. Either coating will need stabilising by drying them thoroughly with moderate heat then wiping with a drying oil or well thinned varnish to fill pores in the surface, then wiping off as much as possible of the excess before it dries if you want it to be durable and scratch resistant. Beware of light blueing as it can act as a semiconductor so may not have a high enough resistance. |
| rebelrider.mike:
Finally got all the plates cleaned down to bare metal! I spent a while looking for ways to get black oxide on the plate, and I think this video pretty much sums up the details pretty well: I've already started degreasing with acetone. It's what I normally use on metal that I'm about to paint. Not sure if etching is needed, as I've just run them all on a scotch-brite wheel, but it's easy enough, and I've got the distilled vinegar. I've got the salt, but I'll have to go get some hydrogen peroxide. Unless I can find some around the house... And it turns out I've already got a little electric burner, so I won't be doing this in the kitchen, LOL. I think I will use deionized water for boiling. I've got pretty hard water, and deionized is cheap, even for me. :) |
| bson:
--- Quote from: rebelrider.mike on October 17, 2018, 03:59:22 am ---I'm not sure how I want to label them yet. Sharpie, or maybe something a little fancier. Not sure what. --- End quote --- How about a lettering stencil and black nail polish? Or a stencil and a sharpie for that matter. |
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