I have made a 35 gallon plastic barrel into a rust removal device. There is about 25 gallons of water in the barrel. I fastened 4 vertical electrode bars on the inside walls of the barrel and connected them together. The part(s) to be derusted are suspended with haywire from a bar lying across the top of the barrel. I added about 2 cups of hydrochloric acid, pool acid.A 12 volt, 10 amp battery charger is connected to the system and small bubbles just stream off of the part. The first part was a rusty trailer hitch. It cleaned it up nicely.
Someone said it was the voltage that does the derusting and you could use 1 1/2 volt and 9 volt batteries. My rust remover drew 4.5 amps when I did the hitch!! It took 8-12 hours to remove the heavy rust. Not bad at all. I need to add 4 more electrode bars inside the barrel. Actually, if anyone is contemplating making one of these, I would suggest a 55 gallon metal barrel. It wasn't practical for me.
My question to the forum is: Is there a better solution than pool acid for this task. I used acid because I couldn't find the soda! But the acid sure works. In fact I think I will add some more and raise the current to 6-8 amps to speed it up. It's outdoors because of the fumes and hydrogen that it produces. Connect and disconnect the power well away from the barrel.
I purchased a 13" South Bend lathe that has been stored for 15-25 years under cover here in Oklahoma. It is doing a great job of derusting the light rust on some of those parts.
I am pleased.
Noel, I have used bakeing soda and electrosol dishing powders with good results. I read though that you can make your own washing soda by putting the bakeing soda in a pan and heating it in the oven for 3hrs on 350 and that gives you washing soda. KB
noel. how do you make the battery charger connections? do you have a picture of your setup? thanks.
Check out these past threads on the subject of rust removal by electrolysis.
Bill Here is a web site that shows the connections. I think you need to use plastic containers.
The muratic acid will disolve the rust without the electrochemical etch so don't forget to neutralize the acid with amonia or laundry detergent. Make sure to wear a mask when neutralizing because the gases are released. if not neutralized, it will kept disolving rust and iron. Your solution is probably very weak but still it is necessary.
I would be careful with lathe parts whose tolerances must be kept and of course all load surfaces. Remember the acid doesn't just get rid of rust but the iron too. I would use a brass brush and three in one oil only for these critical surfaces, then use the lathe and reevaluate the necessity of removing rust further.
I'm sure you are aware of these issues but "just in case" No intent to sport with your intelligence, I just felt obliged to add my two bits.
This site has good advice about neutralizing and safety issues.
A lot of people use Arm & Hammer washing soda. You may have to try several stores before you find it, but it's around.
I use the Arm & Hammer washing soda and have found it at Kroger in the soap isle.
I also use Arm & Hammer laundry detergent in mine and YES it does work on rust and grease. As was said before you need to use a plastic container since this will eat a hole in steel drums. Also it will eat your wire in half after one or two parts are done this way so watch that. It is a good idea to read about the safety part of doing this so you don't blow up your shop from the gas or anything but if you have it outside you should be OK. I have used 2 12 volt chargers in a 50 gal. plastic drum and old mower blades work good as electrodes and they are free! Just do your homework before you do any hardened parts or anything that you don't want to become brittle. I think something was said about that in some of my reading about this as well as don't use it on stainless steel because of toxic waste it put out.
Lets get this straight. The Muriatic acid is what removes the rust. You don't need any electrical current. When you are dune you must neutralize the acid with baking soda in some water. If you don't, the acid left on the part when exposed to oxygen (air) will cause more rust on the part than before you started. I neutralize the acid then apply some metal prep used by body shops to prevent any future rust.
glen chaffin i believe that metal prep is essentially phosphoric acid deluted.if so then how can it prevent future rust without it being neutralized also?
The only additive I use is the washing soda works good for me, off the battery charger.. Cleaned a Ford monkey wrench last week looks great.
Regarding rust removal by Muriatic Acid. One problem with the neutralization step is that, after flushing the baking soda off with clear water, it automatically begins to rust, as the water dries. By the time the water finally dries you have a brown film of rust to contend with. The "Porter Paints Metal Prep" contends with this film of rust, removing it and microscopically etching the surface for priming.
You can decrease the formation of the film of rust by flushing the baking soda off with plenty of hot water so that it heats the surface of the metal, which makes the water dry faster, so the rust film has less time to form. Also, have a hair dryer handy to blow dry the water off, using the high heat setting. If you get the water off fast enough, you may not even need to use the metal prep. Jim
Surface rust after the Muratic Acid (M.A.) procedure depends on the crystal structure and type of metal. In my experience, if you use M.A. neutralized with amonia it will sometimes turn black on cold or hot rolled steel which must be the oxidized state of the alloy additives in the steel or a chemical reaction of the amonia with iron. On cast iron you will get a very thin (molecules thick) red Fe oxidation which has almost zero effect on the adhesion properties of any properly formulated coating like primer, undercoat etc. By useing an etching primer in this case is fool proof with unpitted no flake castings.
I would never use M.A. on body panels if they are pited or flaking because the acid will penetrate micro spaces in the crystal structure of the metal and the amonia can't displace it or neutralize it in some cases so it just continues to disolve the metal. The only countermeasure I know of, in my limited experience is to gas out the panel with heat which I wouldn't do because of safety issues.
Someone on an old thread related a story of someone useing the M.A. method and after a while all that was left was the paint.
M.A. is a hazardous operation (I use it full strength which is about 32% hydrocloric (in water) out of the bottle so if baking soda does the trick and if it is less hazardous then I would definately go for that procedure.
The electrolysis used here is a mystery to me but I wouldn't go as far as to say electrolysis doesn't help. The only thing I can figure out is that the process might help separate the rust from the iron and then etches the metal. What color are the cathode and annode probes when this operation ends or does the weight change before and after?
Here is an easy site for understanding the process. It doesn't mention corossion removal as a standard procedure but does mention corrosion prevention.
There must be a chemist or metalurgist amoung us.
Here's another site that explains electrolytic rust removal.
The wash soda method has been proven to work. When you're done with it you can pour it on the ground or spray your roses with it to kill the aphids. Why mess with dangerous chemicals? This it just laundry detergent
Thanks Verne for the site posting. I'm getting a nice collection under rust for browser "favorites". I'm going to try one of those soda electrolisis projects they list.