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lost_cause
12-15-2014, 08:59 PM
this weekend i picked up a couple used 5c collets at a local used tool shop and they had a couple spots of rust on them - one had the rust on the taper so definitely didn't want to use anything at all abrasive on it. i've got a quart bottle of evaporust that i've used to clean a 4-jaw and a bunch of other odds and ends, and even though it is now very much black it is still pulling the rust off of whatever i put in it.

so, those of you who have used this stuff already know that when well used it will turn your parts black. have any of you ever found a way to lessen the blackening after the fact? i knew going in that it would turn these collets black, and i wasn't disappointed. these are tools, and i'm a believer in function before fashion, so this doesn't bother me. i'm mostly curious for future applications where i may need or want the part to retain a slightly brighter appearance. i've used this stuff enough to know that even clean evaporust will leave a dull gray finish, but i thought someone may have had some success here. i did a little searching and the only thing i saw was people saying to dunk it in fresh evaporust afterwards to lessen it. another said wd-40 & scotchbrite, but i'm really looking for non-abrasive if there is anything.

i'm actually thinking of keeping this grungy solution to try deliberately blacking some parts. of course with my luck it will probably fail to leave a consistent finish when i really want it to.

vpt
12-15-2014, 09:06 PM
I am interested as well. I honestly didn't expect the black parts which makes me use evaporust less than I would normally have.

RussZHC
12-15-2014, 09:11 PM
WAG but I had always chalked it, the discoloration, to some part of the process similar to those solutions that act on rust to convert it but not really having to do with removing it.

Good question...most everything I have used it on has been headed for paint so it never has been an issue (frankly I don't know that I would use it on something that is precise in any manner, more that there has been loss of material from the rusting action than anything else)

Ohio Mike
12-15-2014, 10:25 PM
Much of it will wipe off if you clean the parts when they come out of the solution. I often use a hot water wash which warms the parts allowing it to dry before the rust sets in. I also use WD-40 as a cleaning agent too Its the one thing its good at. I use a soft wire brush on some things (castings etc) and *soft* Scotch-Brite to polish the more delicate parts. There are a million kinds of Scotch-Brite, pretty sure I'm using light grey ultra fine.

lakeside53
12-15-2014, 10:39 PM
yep.. just wash in hot water with the white scotch pad; oil immediately. Don't leave in excessively long and use clean ER if you care. Make sure you full immerse the object you'll get "erosion" at the air-ER interface - i.e. an etched line.

"Darkening" occurs more on hardened (high carbon?) steels than soft. Here's an example - was a badly rusted hammer head that was completely immersed. You can clearly see the heat treated areas.

http://i238.photobucket.com/albums/ff150/lakeside53/misc%20linked%20uploads/AND_0603cropCustom.jpg (http://s238.photobucket.com/user/lakeside53/media/misc%20linked%20uploads/AND_0603cropCustom.jpg.html)

Forrest Addy
12-16-2014, 06:08 AM
I've never used EvapoRust. Look at the "ingredients" panel on the label. If it says phosphoric acid, the black is most likely residue of the acid's action. It will scrub off to some extent but only steel wool or a light abrasive will remove it. You could use a green Cratex stick but they are expensive. 1200 grit wet or dry is very gentle and controllable; you'd have to scrub a fair length of time to jeapordize a precision fit. I prefer a ScotchBrite scouring pad, the fine or very fine grade. I can't seem to find the color code but I did find this:

http://solutions.3m.com/wps/portal/3M/en_US/3MIndustrial/Abrasives/Products/~/Abrasives-Product-Catalog/Hand-Pads-Rolls-Abrasive-Sheets-and-Sponges/Hand-Pads?N=7581709&rt=r3.

I never found the black staining objectionable. It renders the surface its on nearly rust proof and the film is so thin it's almost dimensionless. Many of my tools have this gray or black smut on them and I've cleaned up and dunked all my old-school Armstrong and Williams tool holders in a hot solution of Jasco Metal Prep which is I suppose pretty much the same thing as EvapoRust. I think my poor man's blackening looks nice and they won't rust on the shelf.

If you find the staining esthetically offensive, I suggest you clean up and blacken all your collets. At least they would all look alike.

Ohio Mike
12-16-2014, 08:22 AM
I've never used EvapoRust. Look at the "ingredients" panel on the label. If it says phosphoric acid, the black is most likely residue of the acid's action.

It does not contain acid, it uses selective chelation.

michigan doug
12-16-2014, 08:53 AM
A cotton buffing wheel and a fine buffing compound will take the black off and leave a nice finish.

Technically it's abrasive, but doubtful it will change any dimensions by even a tenth.


Sometimes, I want the black effect, and sometimes I don't. Sometimes it cooperates, and sometimes it doesn't.

It does remove rust very effectively though...


doug