Electrounrusting New question,old topic

[1-800miner]

I have several drums of rusted hardware. Nuts, bolts, washers, tools that I want to clean up and salvage what I can.
I know, some one will say to buy new and sell this stuff for scrap. Scrap price is down and hardware prices are up.
I will salvage what I can.
I bought some Evaporust and it works well for small batches but pricey.
I think my best bet is electrolysis.
How do I get electric contact with every part when I put a basket full in the dip?
The idea I have is to have two baskets and dump the goods from one to another, then put it back in the bath.
Sure would like to single batch the stuff but I don't see how.

[ed_h]

You could make a cylindrical basket and tumble them.

Have you eliminated phosphoric acid from consideration?

Ed

[kendall]

Just wondering, would a 'dump' of screws/bolts etc in the bottom of a bucket with a conductor buried in them work for electrolysis?

phrased that way because it seams that if all the components in the pile are making good contact it seems to me like it would work,at least for the majority of them.

[brian Rupnow]

For "several drums" It isn't going to work. and although "evaporust" works, it wouldn't be cost effective for the quantities you seem to have. Consider a tumbler barrel with sand. Not beach sand--the wave action has rounded of all of the cutting edges. Use sand from a pit, or better yet from a crusher.

[metalmagpie]

You could make quite a bit of progress just tumbling those parts against themselves. If you threw in a few handfuls of plastic vibratory tumbling media, some water and a sliver of soap it would work better yet.

If I had your problem I'd find a metal mesh basket or make one. I'd suspend the basket from a wire or two in a bucket. Hang the wires onto a piece of wood across the top of the bucket. Put some metal down the sides of the bucket (actually I'd wrap sheet lead around the inside of the bucket). Add water and washing soda. Hook the basket wires to the negative terminal and the side metal to the positive terminal and apply power. Every so often turn the power off, take the basket out, and shake it to expose new rusty stuff. Generally the stuff on the surface will derust much faster than the stuff below.

metalmagpie

[1-800miner]

If I had your problem I'd find a metal mesh basket or make one. I'd suspend the basket from a wire or two in a bucket. Hang the wires onto a piece of wood across the top of the bucket. Put some metal down the sides of the bucket (actually I'd wrap sheet lead around the inside of the bucket). Add water and washing soda. Hook the basket wires to the negative terminal and the side metal to the positive terminal and apply power. Every so often turn the power off, take the basket out, and shake it to expose new rusty stuff. Generally the stuff on the surface will derust much faster than the stuff below.

metalmagpie[/QUOTE]

That's the plan.
I am going to split a plastic drum for the vessel. I think a shallow basket would be better than a deep one

[lakeside53]

I'd bead blast the lot!

Or... Concrete mixer with wet coarse sand (yep.. it really does work).

[Glug]

The problem with using electrolysis on the mystery metals you described is some of them will probably contain cadmium, chromium, nickel, and other metals. Those will end up in the solution, and I think they call that Hexavalent Chromium. That's very bad stuff, and it is verrry difficult to dispose of properly.

[v860rich]

A friend of mine had a fire and he used a small cement mixer with sand to clean all his tools.
When he finished a batch they were good enough to use but all plating was gone.
Over time a lot of them broke, due to the intense heat they were subjected to.

THANX RICH

[reggie_obe]

The problem with using electrolysis on the mystery metals you described is some of them will probably contain cadmium, chromium, nickel, and other metals. Those will end up in the solution, and I think they call that Hexavalent Chromium. That's very bad stuff, and it is verrry difficult to dispose of properly.

I recall that the problem occurs when you use stainless steel for the electrodes. Have not heard that is an issue when cleaning plated materials.

[J Tiers]

It seems to be true that most "tools" and hardware will be already damaged sufficiently to be very questionable.

Any Allen, Grade 8 or other heat treated alloy steel bolts etc will be back to a state which is probably about that of ordinary A-36 steel. Relatively low strength due to being annealed. Actual will depend on alloy.

Many tools which one does not initially consider to be "hardened steel", are actually somewhat hardened, as they must be to do their job. They will also be more-or-less annealed.

Anything HSS is a crapshoot. It "probably" did not get the special heat profile needed to actually anneal it, but you do not know.

So, I would use the cheapest process to attack the problem, which also promises to be effective. That is probably the tumbling in some form of mild abrasive, such as sand. I'd use a good deal of sand, to minimize the amount of pounding of one part against another. That normally does a bolt or a tool no good, especially if it may be softer than standard. It is not great for hard HSS, let alone anything else.

I agree that electrolysis is a good cheap solution which has less chance of impact damage. The problem I see is getting electrical contact. Rust is not a good conductor, to say the least. So a bucket of rusty items may, or may not, get effective contact and participate evenly in the de-rusting process.

Your best bet may be a combination. Do some tumbling, which should get off a lot of "bulk rust", and then follow up with the electrolysis for final cleaning. You may find that you will discard some items and not NEED to go further with them.

[ironmonger]

The problem with using electrolysis on the mystery metals you described is some of them will probably contain cadmium, chromium, nickel, and other metals. Those will end up in the solution, and I think they call that Hexavalent Chromium. That's very bad stuff, and it is verrry difficult to dispose of properly.

Hexavalent chrome is bad stuff, but as I understand it, it is more of a problem when welding.

One of the original threads that described electrolytic de-rusting warned about the hex chrome, but the author later retracted his comments about the generation of hexavalent chrome.

I found this thread about derusting from a reliable source. Check it out for yourself.

https://www.finishing.com/340/01.shtml

seems to lay to rest the hexavalent chrome problem. I started using a plastic pail with iron an iron anode and have since moved on to a stainless soup pot for small stuff. Anode and pail all in one :>)

[Glug]

I found this thread about derusting from a reliable source. Check it out for yourself.

Interesting, but I'm not sure that is very authoritative, given the many other sources and how high the stakes are on this. Also, what about the cadmium and other plating? Doesn't that get stripped and end up in the water?

I don't think you should pour something on the ground unless you're comfortable growing vegetables in that spot.

[1-800miner]

I have an old, ruined job box in the corner. As I sort and organize I am finding lot of useless, soft as butter tools.
They get tossed into the box for a new life as Chinese milling machines.

Much of the bolts that I will derust used to be grade eight. now they are grade two. But they are better than nothing at the moment.

One of the hard parts of this process is tossing a custom tool or jig that I spent time building and now is worthless.
And trying to figure the best layout of this new shop. How to make efficient use of the space.
The old shop grew by one piece at a time and got shoved into an available space. Organized chaos.
New one is all open space asking me what to do. Well sort of open space. I put stuff under the roof to protect it until I can figure out a permanent home for it.

Speaking of a home. This Nichols horizontal mill is in my way and if you come with a truck I will load it for you and give you a complimentary beer.

[MattiJ]

It seems to be true that most "tools" and hardware will be already damaged sufficiently to be very questionable.

Any Allen, Grade 8 or other heat treated alloy steel bolts etc will be back to a state which is probably about that of ordinary A-36 steel. Relatively low strength due to being annealed. Actual will depend on alloy.

I agree that electrolysis is a good cheap solution which has less chance of impact damage.

+ anything that has sharpened edge or is (was?) hardened would be suspect to hydrogen embrittlement in electrolytic cleaning. Same problem with acids.