Rust removal

" (indeed this is one step in the "rust bluing" process that was historically used to put a protective coat on firearms - they also traditionally used urine to create the flash rust on the polished metal.. amazing what urine was used for back then.. steel bluing, dying - traditional indego was done in a urine base, hide tanning, gunpowder, and even tooth whitening! :eek:)"

Did you know that urine was the first organic compound artificially produced? Ah, the romance of history.

Did you know that urine was the first organic compound artificially produced? Ah, the romance of history.

Yup yup to the great advancement of science the world over!! It would have been an interesting time to live indeed. To quote the wikipedia article:
"This was the first time an organic compound was artificially synthesized from inorganic starting materials, without the involvement of living organisms. The results of this experiment implicitly discredited vitalism — the theory that the chemicals of living organisms are fundamentally different from those of inanimate matter. This insight was important for the development of organic chemistry."

Technically it was urea, not urine since urine is a rich mix of substances of which urea is only about 60% of the solids (liquid gold if you lived 186 years ago).
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Indeed one of the more memorable stories lines was around extracting phosphorous from urine in Neal Stephensons "The Confusion" (only really recommended if you are an exceedingly patient reader). But the story wasn't really all that far off from the actual discovery of phosphorous in 1669 by Brand:
"Around 1669 he heated residues from boiled-down urine on his furnace until the retort was red hot, where all of a sudden glowing fumes filled it and liquid dripped out, bursting into flames. He could catch the liquid in a jar and cover it, where it solidified and continued to give off a pale-green glow. What he collected was phosphorus, which he named from the Greek word for "light-bearing" or "light-bearer."

Its probably worth noting that this is horrendously dangerous as phosphorous is highly poisonous, really quite explosive and smells like nothing you've probably ever experienced before (yes bad enough it should probably be listed as a danger). Since I'm sure most of you were by now getting out the collection buckets and getting ready to do this at home (at least you'd be able to make real strike anywhere matches again) :wave:
Thanks, Ryan. Loved the pictures. Looks like a tidy solution. I gather the part is suspended under the wood. Guess I have a shopping list now. Goodness knows I have more than a little rust on which to practice! :D

I wonder about the aluminum foil polishing ball process. What's up with that?
Yup I believe he just hung the parts from the wooden bar to keep them away from the electrodes on the side.

Reminds me I was going to also forward this idea for small parts:

The aluminum and autosol bit I'm a lot less sure on.. but found it intriguing.

The Autosol part makes sense because its just metal polish. The aluminum foil bit is interesting though.
I suspect that its mostly because the al-oxide is an abrasive (same as used in much sandpaper) and would be a fine "grit" from the foil:

But its possible that there is also some interesting chemical reactions going on as well:
I'm certainly FAR from positive that you'd get the same exchange between steel and aluminum (my chemistry schoolin is way to faint to recall at this point..). I do know that you can get galvanic corrosion points between aluminum and steel though so it seems plausible. I thought that was a pretty cool way to "polish" silver anyway :D
Well, Paul, I am gathering the things needed and will document the process. I will prepare the 'toot' if the PTB want to keep it for posterity.
Thank you for the links, bookmarking for grampa's old saws. (also need to learn to use the saw set)

Hey Randall, my only advice on the saw set is to not get to overtly ambitious with it. It's real easy to overset the teeth and difficult to set them back. You can remove mild overset by dining the sides (which you want to do anyway to remove the sharpening burrs) but if they're too far over that don't cut it. You don't generally want to wrench them back and forth our you'll weaken the root so often the best solution is to take another couple passes with the file.

The other problem with oversetting is that you have to work harder to use the saw because it now has a wider tooth profile so you're removing more wood. That also ends up having a negative impact on your cut accuracy (easier is more accurate because.. well it is anyway :D)
For this reason a lot of folks prefer the wrench type sets which are actually pretty easy to make yourself and give you a better visual/tactile feel about how far your moving the tooth. Hammer seeing is also more controlled (for the amount of set) because you are against a fixed angle on the anvil but requires a fair bit of finesse (which I don't possess :D) to control the strength of the blow.

I'd start by cleaning them up and giving them a light sharpening and not set them at all. Only start looking at setting them if they'd binding, otherwise the don't need it. Some of the better made saws with tapered plates need very little to no set if used on dry and had woods. Most saws want some on green woods though. That's why I need the several dozen I've accumulated so I can have them tuned for different uses.. My story and I'm stickin to it :D
Here's my two cents....

I don't. Although I don't have coastal fog to deal with, I always plan to paint/polish/etc the part within a few days. Remember, electrolysis will leave a gray coating on the piece that will need to be removed via wire brush/wheel. I take my parts out, dry them EXTREMELY thoroughly, then do the wire cleanup right before paint, which, as mentioned, could be immediately or as late as 2-3 days later. The gray crud on the object protects it from rusting.

Another thing to mention is you need a VERY GOOD electrical connection to the rusted part. Whenever possible, if the object I'm doing has threaded holes, I will put a couple drops of white vinegar into a hole, let it sit 6 hours or so, then drain it out, then chase the threads. The threads should then be perfectly clean. Put a clean, new bolt into the hole and make your electrical connection to the nice clean bolt. It might just be my bad luck, but I have never been able to simply alligator clip the lead to the object and have it work well, no matter how much cleaning and bare metal it looked like I was clipping to.

We get high humidity here in St. Louis through the summer. When i pull parts out i rinse/scrub off the black residue, hit them with an old towel (and for rough surfaces a hair dryer) to prevent flash rusting, and then hit them with a quick coat of spray primer. If it's a machined surface that needs to be clean of paint, i'll still prime it, then remove the primer and wax it after the part is painted.
A couple of additional notes from my playing with electrolysis:
1 - i've used an automotive battery charger and a computer power supply (12 volt line) with no problem. I like my car batter charger better because it has the amp meter on it - i can tell how much juice is flowing. My computer power source was salvaged for free from an old desktop computer.
2 - don't use stainless steel for the sacrificial anode. As the material breaks down, it releases heavy metal into the water solution, making it a hazardous material that really needs to be carefully disposed of. When using "regular" (not stainless) steel, the old solution can be harmlessly dumped down the drain.
3 - the solution can be re-used over and over again. You may want to skim it off between uses. Others have pointed out that the anodes need to be cleaned off between uses. The gunk that develops on them inhibits the electrolysis process.
4 - the process is self arresting. As the rust depletes, the electrolytic action slows, and the current flow is reduced. You can't "over electolysize" (i'm sure that's not a word) parts.
5 - the off gassing hydrogen needs to be properly ventilated. Do it outside, or make sure you have good air flow.
6 - If your part is larger than your tank and cannot be fully submersed, just do it half at a time. make sure there's overlap. This works fine.