Rust removal

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curtis cutter
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Rust removal

Post by curtis cutter »

I was given a number of 4140 1.25" diameter rods that are about 3' in length. Used from a rock crusher.

I would like to clean them up prior to putting in the stack of misc steel. Is there something you would recommend coating the bars with prior to turning them in order to keep the dry rust from going everywhere?
Gregg
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SteveM
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Re: Rust removal

Post by SteveM »

Get rid of the rust with evaporust. Available at pep boys.

Steve
curtis cutter
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Re: Rust removal

Post by curtis cutter »

SteveM wrote:Get rid of the rust with evaporust. Available at pep boys.

Steve
I will give it a try, I see Walmart has it and I need to go there to get 5 gallons of oil anyway.

Thanks.
Gregg
Just let go of it, it will eventually unplug itself.
Glenn Brooks
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Re: Rust removal

Post by Glenn Brooks »

Ospho also works... Phosphoric acid. Cheaper than evaporust usually. Both this and evaporust leaves a surface residue you can sort of leave alone until using the material.
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Harold_V
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Re: Rust removal

Post by Harold_V »

May sound crazy, but molasses will dissolve rust, as will vinegar and salt. Both work slowly, but require no effort on one's behalf. Just put them in a capped length of ABS or PVC pipe and give them a couple days.

Farm supply stores sell molasses in five gallon containers, used for feed for horses, as I understand it. More expensive that using vinegar and salt, though.

Harold
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oldvan
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Re: Rust removal

Post by oldvan »

I'd use electrolytic rust removal. I have a 55 gallon plastic drum filled with water plus a cup of washing soda, miscellaneous ugly steel for sacrificial electrodes, and a 12 Volt 10 Amp transformer-type battery charger I picked up for $5.00 at a yard sale. The setup thoroughly removes rust and paint without damage to the steel.

I have (4) 32" lengths of rusty thick-wall 2.5" pipe that I'm going to use for the legs on my CNC router rebuild. Later today they will go in the tank, and in a couple days they will be rust-free. A rinse with hot water, an hour in the sun to dry thoroughly, and they will be ready to primer and paint.
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Harold_V
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Re: Rust removal

Post by Harold_V »

Given all the choices, I'd have to endorse the electrolytic removal, a process I have yet to try, but I expect I will in the future. Thanks for the reminder!

Harold
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Glenn Brooks
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Re: Rust removal

Post by Glenn Brooks »

Yes the electrolysis method works well. In my experience the black sludge residue it leaves takes as long to clean off as if I just wired brushed it down in the first place. For some unknown reason, washing it off doesn't work well enough for me when I want/need bright, clean material to work with. Always end up with a grey black sheen, on tools for example. But it certainly will take off the rust. Often have wanted to try the molasses method Harold mentioned. Others have suggested this also. Just haven't found any 5 gal jugs in my neck of the woods.
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Harold_V
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Re: Rust removal

Post by Harold_V »

Glenn Brooks wrote: Often have wanted to try the molasses method Harold mentioned. Others have suggested this also. Just haven't found any 5 gal jugs in my neck of the woods.
Try the vinegar and salt method, then. I've used both systems and found them to work equally well. Total elimination of rust with no residue, as it is dissolved, not converted to a different oxidation state.

If you give this method a go, buy the cheapest vinegar you can find, and use a bag of water softener salt. In the long run, it's the cheapest approach. I paid about $25 for the 5 gallon pail of molasses (last one they had in stock at Del's in Chehalis. They are no longer in business there).

Harold
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BadDog
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Re: Rust removal

Post by BadDog »

I really like the phosphoric acid method. Electrolysis is fine if you've got suitable parts and a suitable tub, and time/inclination to build the (relatively simple if you have the basics on hand) setup. But from what I understand, it's line-of-site only from the electrode(s). Holes and cavities don't get the full effect. At least that's what I recall. Phos is cheap, available all over (probably most convenient at HD or the like) in many forms, and as long as you don't buy in super concentrated forms, it's quite safe. I've never gotten it in my eyes, but I've gotten it on my skin many times. And don't tell anyone, but after noting the mild (basically nonexistent) reaction when splashed on my arms, I've even reached into the solution with bare hands when other methods proved to inconvenient (and sufficiently aggravating). Followed of course by immediate rinse, but no harm was noted. Oh, and it's also what gives Coke products the "bite" that I like.

But to summarize I've used it again and again over years and never had a negative experience. The closest I've had is when I left hardened tool steel in too long and it gets a blackish finish that is VERY tough to remove and the surface takes on a slightly pitted appearance. Staying longer would presumably have made things worse. But for cast iron, the stuff is wonderful. I was gifted what turned out to be a shaper compound off a really large old shaper. It was found by stubbing a toe on something in the ground, and digging it out to find that the toe had kicked the bolt of the tool holder. No telling how long it had been under ground. When I got it, it looked like something excavated from a ship wreck. But I was intrigued and dug out the crud before dropping the whole lump in a tub of phos solution. As it worked at it, I slowly managed to get things moving enough to get it apart. Took a while, but now it actually works beautifully, and you can still see the scraper's marks in the slide way. The steel parts, including the screw were pretty well hashed, but the cast iron came out looking almost newly cast and machined! I did save the steel parts (as much as they could be) for historic reasons (not putting the thing into service), but they are pretty badly pitted. But get this. The paint that was on the non-machined surface is still intact! One of my favorite "display" pieces collected...
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wlw-19958
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Re: Rust removal

Post by wlw-19958 »

Hi There,

I have used oxalic acid for rust removal. It works well.

Good Luck!
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SteveM
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Re: Rust removal

Post by SteveM »

Actually, they are no good with all that rust.

Send them to me for proper disposal :-)

Steve
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