I picked up a nearly free 3 jaw chuck (or a really expensive chuck, but a free mill vise and rotary table). I want to clean it up, but don't feel like attacking it with a wire brush. It's already fully torn down, next I'll degrease next and either pick up some Evaporust or piece together an electrolysis setup from spare crap in the garage.
Any recommendations? I have a modern, smart battery charger and a couple old batteries lying around - I read that I can hook the charger up to the battery, and battery leads up to the tank to trick the charger. Anyone have success with that, or should I go spend a couple bucks at HF?
Alternatively, this may be a good application for Evaporust. I always thought it was more aggressive than it is. I assumed it'd etch the surface and generally remove material - but that doesn't appear to be true. I'm not chasing ten thousands of an inch here, so maybe soaking is the most efficient approach?
Obligatory picture. I'll admit, Tom's Bridgeport thread has me shopping for upgrades for my machine. I've been longing for a horizontal/vertical rotary table for a couple years.
For something like your application I would use Evaporust simply because it works would not hurt the metal or any moving parts. It leaves a nice gray finish you could wipe with a light coat of oil to further prevent rust. The only drawback to Evaporust is somewhat expensive if you need a lot to cover the part. That can be minimized if you can find containers your parts will just fit in. For instance you might fine a pail or bucket the three jaw chuck will just fit in. A plus to Evaporust is you can use it over and over again until it is totally nasty.
Another option you might also try clear vinegar (takes longer) which removes rust and is really cheap at Sam's Club, Costco, etc.
Another option is Ospho (phosphoric acid) that you could put in a spray bottle and just keep the chuck wet with it until the rust disappears. It will impart a gray/black surface finish that can also be given a wipe of oil to prevent rust. This is similar to the Parkerizing Process they do on socket head screws/bolts and other hardware.
Another option is citric acid which comes in powder form that you mix with water. I have not used it but know people who have and is very effective. Also fairly cheap and can be bought on EBay or Amazon. Used solution I'm told can just be disposed by pouring down drain. Do a google seach for "rust removal citric acid" there's a lot of information.
In reply to pirate :
I agree. Electrolysis actually removes a small amount of material from the part, which seems to me like a bad idea for precision tools.
I got decent results on a Parker vise with a long soak in dilute molasses. It's not aggressive, doesn't seem to remove base metal, and is cheep. It does start out smelling bad and gets funkier as it sits, so best done outdoors if possible.
I used Evaporust on the chucks for the 16" lathe and was happy with the results.
Before
After
Molasses is actually a pretty cool bet, but I know it is slightly acidic and might etch. You really are down to Evaporust and Electrolysis; I really wouldn't use any acid. Vinegar is far too weak and would require days of soaking- and anything more powerful than phosphoric will likely etch the metal which you need as intact as possible.
Evaporust works via Chelation- its a process involving at least 2 chemicals, one that pulls the iron out of suspension from the rust via ionic bonds, and a second that bonds with the first chemical to cause the iron to drop out of suspension. It's why spent or used Evaporust is tarry stool black- it's just full of metal. It's expensive, but it will never damage your stuff and can be reused literally until it stops working.
Electrolysis rules if you know what you're doing. You might be able to get away with a setup like that, but only so long as it doesn't boil the batteries and the charger can put up with it. What you should do however, is find an old power brick or charger for a laptop and tear the old charge port off for alligator clips- the less voltage and more amperage you can get (I have one pushing 10A at 12V) the more furious the process works. It doesn't hurt steel, but it WILL corrode aluminum. Make sure you're using Washing Soda and not baking soda, the former has far more negative ions which makes the process literally take half the time. Also, rotate the part and change you're sacrifical electrodes frequently, and make sure it's close but never touching.
Evaporust it ia. $16/gal on Amazon isn't the worst thing. Hopefully 2 gallons will be enough for to submerge the chuck pieces, may need to reorient if I can't fully submerge.
Thanks, next update will hopefully be some clean metal!
Cleaned up well, I'm now a believer!
Degreased it as well as I could, soaked for 18 hrs and turned it over a couple times. Then a little wire brush and steel wool revealed a cracked scroll. I didn't grab any pictures of how it came out, was kinda bummed about the crack. The last picture shows how much it opens when clamped.
In hindsight, it looks like the whole casting might be cracked?
Phew, false alarm. The line in the bottom of the dovetail doe the jaw is just a line of demarcation where the it sat in the Evaporust.
Also, my bench gained some weight this week!
Put Evaporust back in jugs. It can be used over and over until it turns black and quits working. Great stuff!
