Rust removal through electrolysis?

[Caimlas]

I read a while back that it was possible to remove rust through electrolysis using washing soda (sodium carbonate) as the electrolyte. I've looked high and low here locally, and I've been unable to find the washing soda.

However, baking soda is sodium bicarbonate (one less sodium and one more hydrogen atom). I know this is not the same thing, and that this kind of difference is a substantial one, however: I saw "on the internet" somewhere that it is possible to substitute baking soda, if you first put it in a pan and heat it, "letting off water and carbon dioxide"; while I believe this chemical alteration is incorrect, my high school chemistry isn't terribly good; can anyone verify this would still 'balance'?

If this process isn't the same, is there any reason why using baking soda/sodium bicarbonate will not work for rust removal in this fashion? Is there a specific reason why electrolytic rust removal requires washing soda for electrolyte, and can't use something else?

(FWIW, I'm trying to remove rust and blue from some gun parts, but want to take off as little metal as possible in the process - and haven't access to sand/media blasting.)

Many thanks.

 

[rondog]

I haven't done it, but I've read the process and know folks who HAVE done it to car parts, and it's supposed to work very well. As far as the washing soda, it's supposed to be available at most any grocery store or WalMart.

I don't think I'd dink around with substitutes, you might generate something dangerous. I am NOT a chemist!

 

[Jim Watson]

Without doing the chemistry research or grocery shopping, I can only suggest:

1. Mailorder
http://www.drugstore.com/search/sea...da&N=0&No=20&Ntx=mode+matchallpartial&Ntk=All

2. Test baking soda on a rusty piece of scrap steel.

 

[rcmodel]

Just buy a bottle of Birchwood-Casey Blue & Rust Remover.
It will take it down to bare steel for 4 bucks, with no mess or worry.

http://www.cabelas.com/cabelas/en/t...=birchwood casey bluing remover&cm_ite=netcon

 

[Canuck-IL]

Or a 6 oz tub of Naval Jelly at any hardware store ... just don't get it on any bluing you want to preserve - this stuff is instant bare metal.
/Bryan

 

[rcmodel]

And it's semi-instant etched surface.

IMO: Much too agressive for gun work.

 

[Caimlas]

Just buy a bottle of Birchwood-Casey Blue & Rust Remover.
It will take it down to bare steel for 4 bucks, with no mess or worry.

BTDT. Not only does it work poorly (slowly) and somewhat inconsistently, but it also leaves a pretty big mess. Before you can get it all off, the part has already started to rust again (within seconds).

Likewise for Naval Jelly - BT,DT. It works fairly well, but it's an even bigger mess than Rust Remover. Additionally, as it's an acid etch, it will leave a (very ugly, IMO) pickling "patina" on the metal. No thanks.

I DID test out baking soda last night on some older/rusted tools; it works reasonably well, working under the flaked rust and converting the lowest level of rust to what looks like black rust oxide (which has the same molecular size as the steel and inhibits further and penetrating rust). After pulling the part (a screwdriver) out of the solution it required a fair amount of rubbing with a cloth to get the flaked-off rust/grime off the surface of the part (I used an oiled cloth for this and then sprayed it down with some WD40 afterwards).

 

[fguffey]

Caimlas, I use vinegar with out the battery, 4 to 6%, if I want to slow the process, I add water, and before I start, I can drink it. I have used this method on old tools and cast iron pots and pans, a very slow and safe method.

I also use vinegar to clean brass cases cases, soak for no more than 15 minutes then wash, dry and tumble, vinegar can reduce tumbling by a day. if you want to speed the process use H2S03 or H2S04, dangerous stuff, if the door bell rings and you check to see who is there, nothing left.

http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/

http://myweb.tiscali.co.uk/andyspatch/rust.htm

F. Guffey

 

[fguffey]

Caimlas, I use vinegar with out the battery, 4 to 6%, if I want to slow the process, I add water, and before I start, I can drink it. I have used this method on old tools and cast iron pots and pans, a very slow and safe method.

I also use vinegar to clean brass cases cases, soak for no more than 15 minutes then wash, dry and tumble, vinegar can reduce tumbling by a day. if you want to speed the process use H2S03 or H2S04, dangerous stuff, if the door bell rings and you check to see who is there, nothing left.

http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/

http://myweb.tiscali.co.uk/andyspatch/rust.htm

F. Guffey

 

[jacobhh]

Phosphoric acid & sulfuric acid(H2SO4) are the active ingredients in
naval jelly. It seems to me they've much diluted the DURO brand
recently, but it's still pretty corosive.

Try the vinegar, it's worked for me. Use the regular white, balsamic is
messy and expensive and probably doesn't work as well.

 

[Howard Roark]

Is there a specific reason why electrolytic rust removal requires washing soda for electrolyte, and can't use something else?

Baking soda is sodium bicarbonate - NaHCO3, where washing soda is Na2CO3. Washing soda works better because you get more dissolved ions for unit volume. Baking soda will work just as well if you don't mind adding about twice as much. No need to heat it, just use about 1/4 lb per 5 gal dihydrogen monoxide (water).

 

[Mac's]

I've tried the "electro-cleaning method" and although it does work, I'll stick to my abrasive blaster. (I know you said you don't have access to one)

There were a couple of interesting things that I discovered while researching and experimenting. The power supply that I used is variable for both voltage and current.

1..The higher the voltage, the more thorough the cleaning of the part was but it seemed pretty gentle. (I experimented with rusty bolts)
2..The higher the current, the more aggressive the cleaning was. It actually ate metal pretty quickly.
3..After a few minutes in the tank under power, the voltage and current use would start to drop. A good shake on the part at the end of the wire would bump it back up again. (Maybe that was because of #5 below?)
4..Positive attracts and negative repels. If you get it hooked up backwards in the tank, all of the crud that was removed from earlier experiments will leap onto the part that you're trying to clean. The finger sized bolt ended up looking like a furry rusty tennis ball after five minutes.
5..I didn't know until this post that there was a difference between Washing soda and Baking soda. All of my experimentation was conducted with Baking soda.
6..I used a metal tank for my experiment with the tank being Positive and the part being cleaned Negative. The crud being cleaned off of the part would coat the inside of the tank and after a while, would insulate it so I would have to clean the tank inside. Then it would start cleaning again. If I was doing it for "real" instead of just playing, I would use a pastic tank with a copper electrode hanging on the side. Then just pull the electrode out and clean it once in a while.

For general use in my shop, it's too labor intensive. I have a huge abrasive blaster with an even huger compressor. However, if I had no access to air pressure, it would work.

One interesting thing that I did discover about electro-cleaning, is that it's flat-out incredible what it can do for a nasty old barrel bore on a mil-surp rifle. I used a rubber cork in one end of the bore. A piece of thin music wire (Hardware store) pushed thru the center of the cork and up thru the bore was the Positive electrode. The barrel is the Negative side. If the wire touches the bore, it'll short out the power supply and stop the process. At the top end, I taped a funnel around the barrel and supported the music wire across the top. Pour the solution into the funnel until the bore is full, turn on the power and the crud will foam up thru the top of the funnel. I was impressed and that was with Baking soda. I'll have to try it again with Washing soda. But remember: You're using electricity with water. It's low voltage (20 Volts or so) at the electrodes and wont even sting but unless you're using a battery, there's higer voltage somplace. Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons
http://www.shootiniron.com

 

[alsaqr]

I often use a low amp battery charger, a plastic container some new chain and lye to de-rust antique tools, guns and artifacts. Soon I will use the process to remove moderate rust from a .50 caliber linker/de-linker.

1. Get a 5 gallon plastic bucket. Get an 18" piece of 1x4 board and drill two holes in it about 8" apart for the chains.

2. Tie the item to be de-rusted to the chain designated negative-.

3. Put the item to be de-rusted into the bucket. Put the board over the bucket. Bring the chains up through the holes in the bucket.

4. Put nails through the links to keep the chains from falling into the bucket. Allow the chain designated positive+ to dangle just off the bottom of the bucket.

5. Put 2-3 gallons of water in the bucket and add a can of lye. Stir the lye into solution.

5. Connect the negative lead of the battery charger to the chain that has the tool attached to it. Attach the positive lead of the battery charger to the chain designated positive+. Set the battery charger on 2-6 amps.

6. Plug in the charger.

When the solution bubbles like coke in a glass it is working properly. If it does not bubble there is a bad connection. When all the rust turns to stuff that looks like black dust it is done. It usually takes 30 minutes to an hour to de-rust a tool that is moderately rusted.

After the process is complete, put on some kitchen gloves and wash off the now de-rusted item with a garden hose. Next rinse the item with boiling water.

Very heavily rusted stuff should not undergo this process. It will come out all pitted.

BTW: I have used a modification of this process to remove rust from the bores of gun barrels.

 

[ranger335v]

"...want to take off as little metal as possible in the process - and haven't access to sand/media blasting."

I don't really have access to normal sand blasting gear either but wish I did. What I do have is an old home shop air compressor and find it very useful for a lot of reasons. I recently added a small hand held pistol shaped sand blaster "gun", thing with a small sand hopper on top, got it for something like $12-15 from a Harbor Freight Tool store. Using "Play Sand" from Lowes for media, it has been very handy for rust removal on small tools and rusty sheet metal before painting.

Every home handyman needs a small air compressor and impact wrench/ratchet wrench/nail/brad/paint spray guns but few of us can justify the cost of high quality tools for the limited uses we have. Harbor Freight sells mostly Chineese tools but, for my needs at least, they are good enough and the prices are right! I've almost gone broke saving money on tools the last few years and couldn't be happier, home chores are MUCH easier now!

(HF sells inexpensive dial and digital calipers exactly like those sold by the big reloading companies but for as little as $12, on sale, which is often. And they have vib tumblers that look exactly like those from Midway, for $39 on sale, which isn't much better than Midway's sales but...no shipping! ??)