Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
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Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
bugimike
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Morris
Yoda
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Here you go:
https://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm
You owe me five bucks.
https://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm
You owe me five bucks.
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Here's another link: https://www.davidbradley.net/ERR.html.
It's basically pretty simple, and you don't need to pay for the info. Dump the rusty item in a bucket of alkaline solution (I use weak solution of sodium hydroxide [lye] drain cleaner), pull an electric current through it, and the rust loosens considerably. You might have to brush it a bit or wipe it with a cloth to get it to fall off. I don't remember what the current density has to be, offhand, but it's not critical.
The pictures are a little optimistic. The rust will come off, sure, but the lost metal won't be replaced. I have a hard time seeing how you could get as much rust as shown in those pictures with as little surface damage or pitting. But, hey, that's advertising.
Second problem is that the item will re-rust really fast. Most "bare" steel you see actually has some kind of surface treatment, if only a little oiling, so most people don't realize how quickly REALLY clean steel will corrode. So, if you do this, you need to be prepared to do something with it--paint electroplate, or apply whatever other surface finish you plan to use--as soon as it's derusted. We're talkin' minutes here, folks; not tomorrow or next week!
It's basically pretty simple, and you don't need to pay for the info. Dump the rusty item in a bucket of alkaline solution (I use weak solution of sodium hydroxide [lye] drain cleaner), pull an electric current through it, and the rust loosens considerably. You might have to brush it a bit or wipe it with a cloth to get it to fall off. I don't remember what the current density has to be, offhand, but it's not critical.
The pictures are a little optimistic. The rust will come off, sure, but the lost metal won't be replaced. I have a hard time seeing how you could get as much rust as shown in those pictures with as little surface damage or pitting. But, hey, that's advertising.
Second problem is that the item will re-rust really fast. Most "bare" steel you see actually has some kind of surface treatment, if only a little oiling, so most people don't realize how quickly REALLY clean steel will corrode. So, if you do this, you need to be prepared to do something with it--paint electroplate, or apply whatever other surface finish you plan to use--as soon as it's derusted. We're talkin' minutes here, folks; not tomorrow or next week!
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You'd have to have a very big tank!
Might be some trick like brush electroplating, but in reverse: take a brush of some kind, wet it with the solution, attach electrodes and power, and keep wiping. Not very efficient, but it might work. For large pieces, there are probably easier ways to derust them. Like chemical treatment (naval jelly) or just sanding.
Might be some trick like brush electroplating, but in reverse: take a brush of some kind, wet it with the solution, attach electrodes and power, and keep wiping. Not very efficient, but it might work. For large pieces, there are probably easier ways to derust them. Like chemical treatment (naval jelly) or just sanding.
Whitephrog
Luke Skywalker
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For the past couple of weeks I've been using Evapo-Rust by Harris International Laboratories. Not only is it working well on rust but parts like BE seat rails and slides, bonnet stays look almost new. Works on carb parts, door latches with really good results. Just did a wiper motor body and alloy end piece last night. They look nearly new this morning.
Hap Waldrop
Yoda
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I've done electrolytic derusting, it works fairly well, just slow as all get out, lets put it this way, I wouldn't trade for my bead blasting cabinet for it. I can't beleive some skuzzball is on Ebay trying to sell you the method, there are dozens of websites explaining how to do this.
Just to be sure everyone knows--
NEVER put aluminum in a lye bath ("Draino" etc) because if you do you will soon have a melted pile of aluminum oxide where your carburettor used to be, etc. My MGA doors were really nice (just needed to remore the paint) before they went into the paint shop's "cold bath"- they came back looking like swiss cheeze.
Bill
NEVER put aluminum in a lye bath ("Draino" etc) because if you do you will soon have a melted pile of aluminum oxide where your carburettor used to be, etc. My MGA doors were really nice (just needed to remore the paint) before they went into the paint shop's "cold bath"- they came back looking like swiss cheeze.
Bill
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Billm said:
Yes, absolutely true. I should have made the point that the electrolytic method works ONLY for brown iron oxide--rust on steel and iron, in other words.
Actually, if you want to remove oxidation on aluminum, dunking it in a MILD alkaline solution works great. But you don't have to mess with lye, which is dangerous stuff; even ammonia usually works well. No electricity needed.