Best way to remove rust from black oxide?

I recently acquired a face mill that has a glossy black oxide surface
finish. The mill is in excellent condition except that the previous owner
allowed it to develop some surface rust (mostly on the upper surfaces;
probably from sitting around uncovered on a shelf). The surface rust is like
freckles, with most very small, but some spots of 2-3mm dia. Naturally, the
black oxide finish on these upper surfaces (between the rust spots) is also
dull.
I was wondering if there is a way to remove the rust (or majority of rust)
without significantly damaging the black oxide. In the past, when I has some
surface rust on some black oxide impact sockets, I tried the following:
1. Green scotchbrite and kerosene.
2. Phosphoric acid.
3. Salt & vinegar bath.
All three methods removed the black oxide as well as the rust.
How about polishing? That will also remove the black oxide, but perhaps not
as much. Or is there an easy (and inexpensive) way to renew the finish?
Any advice would be greatly appreciated.
- Michael
Reply to
DeepDiver
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Michael,
If the rust is quite superficial, try wiping the cutter with an oily rag, rubbing on the rested spots. If that doesn't work, a wire brush (hand variety, not powered) will usually knock the rust off, then you can follow up with an oily rag. Don't expect it to look like it's never rusted------the damage is done, it's a matter of degree. Still, this will make it look one hell of a lot better.
Harold
Reply to
Harold and Susan Vordos
This may sound a bit cold..but..why bother? Its a cutting tool. Disposable over time. Give it a shot of LPS-3, store it properly and dont sweat the small stuff.
Anyone remember the Tnut quote about spending all your time making machines pretty? Something pithy about "fuck the paint, use the damned thing"
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
Reply to
Gunner Asch
A product called Evaporust. This is a liquid that looks and feels like soap. I have soaked rusted tools in it, and they come out clean and black. It won't restore the shininess, though.
Reply to
Leo Lichtman
Yeah, I think that particular comment really struck home with me. Up until that time he and I had a somewhat bumpy usent interchange but when we both realized that we shared that common philosphy it smoothed out a bit.
Paint was never my strong suit.
Jim
Reply to
jim rozen
Find some Evaporust. Dissolves the rust, doesn't hurt finishes. 2 hours max. Good stuff.
- - Rex Burkheimer Fort Worth TX
DeepDiver wrote:
Reply to
Rex B
Brass wire wheel brush, not brass plated steel. Brass that a magnet will not stick to. In addition the little bit of brass that remains on the tool surface provides some degree of rust resistance.
Reply to
bamboo
4/0 steel wool and light oil is the time tested method for removing rust from blued(black oxide) guns with minimum blue damage. Ask any gunsmith.
Randy
Reply to
R. O'Brian
Thanks Leo and Rex for the tips on EvapoRust; it looks like a promising product for this and many other de-rusting operations I come across. Now if I can just find a local source for the stuff.
- Michael
Reply to
DeepDiver
Actually, it's a carbide insert mill, so it's not exactly "disposable".
Besides, by your philosophy, one could argue that firearms are disposable tools and thus we should not worry about their cosmetic condition. But I'd hate to have a rusty firearm, even if the rust is only on non-working exterior parts.
- Michael
Reply to
DeepDiver
I've noticed, in my few years of following this group, that there are those that see their machines much as a teenager does (did) his car. I recall all too well how important it was to keep it washed and vacuumed. White floor mats and whitewall tires (does that date me, or what?) that were spotless------and paint that never saw dust.
It's different for the majority of us that have worked in the trade, when it comes to our machine tools. While, almost to that man, none of us prefer to have a shop worn looking machine, we also realize that how a machine looks has little, if anything, to do with how it performs. Thus my hatred for rust. Precision surfaces can't be rusted without damage-----but paint can be totally missing, with no ill affects on a machine.
The paint around the spindle on my Graziano, and other places, is long gone, right down to the cast iron, a result of running a chemical coolant that had an affinity for paint. Mind you, I don't wear that as a badge of honor, but the harsh reality is that the machine was a work tool, and coolant was a necessity. If paint had to be sacrificed in order to squeeze the maximum performance from the machine, so be it.
Do I have plans to paint the machine?
No, I do not. I can't get interested in spending that amount of time on something that makes no difference, particularly when it might discourage me from using the machine as intended, trying to avoid hurting the new paint job. I take a realistic approach to my machines. Keep them well wiped and oiled, and use them as intended. After all, they're machine tools, not mantle pieces.
Harold
Reply to
Harold and Susan Vordos
Yep. about $18/gallon at retail. But it's reusable until you can't stand to look at it. Then you can pour it down the drain.
Reply to
Rex B
I don't treat my machines like museum pieces. However, I do care for them as I do all my tools. A well-maintained machine performs better and keeps its value longer.
When I first bought my import 9x20 lathe (my first "chip making" machine, not counting hand tools or bench grinders), I stripped it down to the frame (short of removing the head from the bed). One thing that concerned me was the amount of casting sand and dross still stuck to the inside surfaces of the bed iron. It seemed that sand was constantly sloughing off. I may not have a lot of machine room experience, but the idea of mixing sand with precision ways and tooling just didn't sit right with me. So I took my die grinder and a few carbide and abrasive points, and ground off all the crud from the rough inside surfaces of the bed. I removed over a cup of casting sand and other waste. Then I painted the freshly bright surfaces with POR-15. Yes it was a lot of work, but I feel it was worth it. Mind you, I don't baby this machine. There are plenty of places where the factory blue paint has been chipped or scratched, and even a section on the tailstock where I removed some globbed-on bondo, exposing bare metal. I haven't gotten around to touching up the paint. When I do use this machine, my cleanup is mostly just sweeping/vacuuming up the chips and wiping down the bare metal surfaces with an oily rag. I really don't mind signs of use: stray chips, oily surfaces, imperfect paint, etc. But rust is something I can't stand. Not only is it unsightly, but it is damaging. And it is perpetuating if not stopped.
Now, when it comes to my precision instruments, that's a whole 'nuther story. Those I keep pristine.
- Michael
Reply to
DeepDiver
I don't mind having mantle pieces. But they're seldom the same as machine tools.
This having been agreed on, I do confess to the sort of puttering in my shop that would have somebody fired in a commercial shop. For example, I've done things like made nicer lockscrews for the micrometer collars on my 10L, and done them with Brownell's oxpho cold blue solution to blacken them up.
Also the lock pin for the handlever collet closer - I didn't like the cheesey one that came with the machine, so I reamed the holes one size up and made a nicer pin with some fancy knurling on it. Again I used the Oxpho to tool black it.
I use the machines enough that seeing crummy fittings just grates on my nerves. My hardinge milling machine has definitely seen better days, but it works ok. It came without knobs on the switches though. I took the time to get replacements, with the circular ridge around the outside like hardinge put on it originally.
But paint? Never really do touch the stuff.
Jim
Reply to
jim rozen
As far as I'm concerned, it's still disposable...everything is, long term, considered "perishable tooling" even the machines. And he did say "over time"...even insert pockets get worn.
I suppose you could carry the analogy that far if you wanted to and it would still be accurate...the only thing that changes is the scale. The fact is that unless there is rust in the insert pocket(that would be bad for the insert and all that) or on a mounting face/flange, a little rust isn't gonna hurt a thing in the world.
Luck
Mike
Reply to
The Davenport's
I do have a few rusty firearms. They came that way to me. They will be cleaned up simply because rust will damage them, and ultimately make them unusable. Not so with a shell mill. Shrug
Gunner, with quite a number of rust spotted mills of all styles
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
Reply to
Gunner
Rex, could you tell me where you bought yours retail? I've found online sources, but would prefer a local source.
Reply to
DeepDiver
Interesting that you've found it doesn't hurt finishes. According to the Orison marketing website:
"EVAPO-RUST [is] perfect for removing weapon finishes such as Bluing, Parkerizing, Zinc Phosphate, and Browning. Blueing and zinc phosphate coatings (heavy zinc per MIL-DTL-16232 and light zinc per TT-C-490) can be removed both at room temperature (@30 minutes) and 118 dergrees Fahrenheit (@15 minutes)."
According to them, it eats up finishes (and rather quickly at that)! What types of finishes have you tried that it didn't damage?
- Michael
Reply to
DeepDiver
This is the email they sent me today. " Karl,
I apologize for this belated reply to your email, Stephanie is no longer with the company and her emails have had trouble forwarding. We currently have no distributors in Hawaii, but have some in California. Please go to our website,
formatting link
and click on the distributors tab, look at California. If you are not able to get satisfaction, please call us direct at our toll free number, 888-329-9877. Thank you for your interest in our product!
Best regards,
Howard Crosby"
Reply to
Karl Vorwerk

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