I had a tip a while back about rust removal...put it in a molasses and water mixture, and VOILA, no rust. I didn't believe it. Well, somebody I really respect finally recommended it to me, for a stubborn rust problem, and I tried it. He recommended mixing 1 part molasses to 12 parts water. I also heard 1 LB molasses to gallon of water, and 1:20 ratio, although weight or volume was not specified. I used my calibrated eyeball to mix up the solution, and put a very rusty WWII tail light door, a cast iron oil pump with nickel plating, and a forged steel piece in the same bath, and watched it every day. The first day, most of the rust on the tail light door was GONE! The casting was losing rust, and the forging had noticeable reduction of rust. It continued to improve each day. After two weeks, the tail light is almost whistle clean. The casting is the same, and the plating was not touched. The forging is still resistant, and has a little left in the shallow cast pits on the surface. All of the painted surfaces are untouched. I am really amazed by the progress. I don't know what the process is, and don't know how it will continue to work, but $2.29 of Grandma's Molasses and .00001 cents of Baltimore City Tap Water are really doing a better job than a glass beader. Tomorrow, I am going to the feed store, to buy 50 Lbs of Feed grade Molasses for $18.54, and am looking forward to saving on the sand blasting bill this spring (Oh boy, an ambulance, an MB, a carryall, and a motorcycle- any little bit helps) Has anybody else used this technique? Any tips on technique, other than pour, wait, and wash?
And they laughed at me when I told them about it twelve months ago, if you really want to know what causes it, Phosphoric Acid, (excuse the spelling), is created in the mix, a better solution is 10:1 ratio. The mix will lose it strength after awhile (about 8-12 months), but it's good value for money.
Could try stuff is called RUST-SOLVE and it is manufactured by TSSI in TX by a guy named Doug Fox who is from New Zealand. I talked to him some time ago about the guy in CA who is supposed to be selling this stuff and who never answers his email or answering machine. If you are interested in RUST-SOLVE, don't call the guy in CA (I believe his name is Orme), call Doug Fox at (409) 446-1825 or email him at: email@example.com. By the way, the stuff costs $37.50 + shipping for enough to make 5 gal. It is a crystalline substance that is shipped dry so you have to add water When I first ordered this stuff from Doug Fox he said he is not setup yet to take credit cards so he would ship it and I could send him a check for the proper amount when I got it!
Another way to get rust of metal parts is to soak them in plain household type Vinegar. Use the vinegar straight as it comes from the bottle. Place the part in a glass or plastic container and cover with Vinegar. Check the parts after 24 hours. The surface of the part may look black but just put it under running water and a light brushing will clean it up.
VINEGAR WILL REMOVE THE ZINC FROM BRASS!!!!! SEE BELOW
The acetic acid is attacking the zinc in the brass leaving the copper which probably looks a dull red in color. With prolonged immersion the acid depletes the zinc and the remaining copper is like a sponge, with no strength. It is de-zincification. In South Australia the drinking water is so bad that de-zincification is a big problem for brass water fittings and water meters etc. God knows what it does to people's insides. Brass alloys range from around 60% Copper/40% Zinc up to 70%/30%.
You need to soak and agitate the parts in clean water to dilute and remove any acid left in the pores. Acetic acid is pretty mild so it shouldn't be a big problem. You could also dip them in a mild alkali solution (pool chlorine) to neutralize the acid.
If you want a quick clean use very dilute Nitric acid. It attacks the copper too.
For steel parts phosphoric acid might be better. I use diluted phosphoric acid from the pool shop. You can also use Hydrochloric acid (muriatic) also from the pool shop, suitable diluted, but it tends to promote surface rust afterwards. Check the costs. Vinegar might be an expensive acid compared to bulk pool acids, or even better, commercial grade acids used in plating shops. Incidentally do all this outdoors well away from any metal tools, structures etc because the vapors can rust steel items that are some meters away!
How do I know??
Bill's Electrolysis Page
I can't really recall how I got started with this cleaning process, but I know it was helped along by the antique engine list, and my background in science (and a lot of hard studies at school, so stick with it kids, it WILL be handy one day!).
Basically, what we have here is a cheap, easy way to clean rust and grease, and actually in some cases, paint, from our toys.
What you need:
Container of some sort - a Plastic bucket works really well. More on this later.
Battery charger - big is better, but even a small one able to kick out 6 to 10 amps should do.
Electrodes of some sort. Concrete reinforcing rod works well (re-rod) cut into lengths about 4" taller than your bucket.
Arm and Hammer LAUNDRY soda, also called washing soda.
Small lengths of small chain.
How to do it:
Assuming you are using a plastic, or non-conductive bucket, mix a solution of 5 gallons water to 1/3 to 1/2 cup laundry soda. Mix well so all soda is dissolved. Clean the electrodes so they aren't too rusty - especially at the top ends - they need to make good electrical contact. I take mine to a wire wheel on my grinder and give them just a real quick going over. Place electrodes in bucket, around sides, so clean, rust free ends stick up above bucket. Use wire, clamps, or some means to hold them in place, so that they cannot move freely, or fall into center of bucket. They must NOT EVER touch part to be cleaned, which will be suspended in center of bucket. I use small C clamps. Whatever you use, it shouldn't be copper, and will get a bit messy if it gets into your cleaning solution. Tie the electrodes together with wire, or cables. I use copper wire twisted around the top ends, and have used old jumper cables. All electrodes need to be tied together "electrically".
Suspend part to be cleaned into bucket so it hangs in the middle, not touching bottom, and not touching
electrodes. I place a piece of rerod across top of bucket (see photo below) and bolt a small piece of
chain to my part to be cleaned, and clamp the chain on the rod so that the chain hangs from the rod, and
suspends the part into solution below.
Attach battery charger - place NEGATIVE LEAD (this is most critical!!!) on rod, or metal that piece to
clean is suspended from. Somehow, your negative, or BLACK charger lead needs to connect to the part.
Attach POSITIVE, or RED lead of charger to electrode "grid" formed when you placed electrodes, or
rods, into bucket and tied them all together.
Make sure electrodes and part to be cleaned are not touching, turn on charger. You should within
seconds see a lot of tiny bubbles rising from the part suspended in the mixture. Do not do this inside, or
in a closed area - those bubbles are the component parts of water - H2O - Hydrogen and Oxygen.
Remember the Hindenburg?
See below how the rust and bubbles are attracted to the electrodes? You will need to clean them from
time to time - they will get very covered with gunk, and in fact, after many uses, will have eroded down
and need to be replaced. That is why I use rerod - it's easy to get, cheap, and most of all - SAFE FOR
YOU (unless you attempt to eat it) and your environment! No nasty elements such as stainless steel
would have. You can pour the waste solution on the lawn and it won't hurt it. Do watch out for ornamental
shrubs which may not like iron rich soil, however. No use making your spouse mad!
This could all also be done on a larger scale - get plastic chemical barrels, cut out the top, and you can
make a 15 or even 30 gallon cleaning tank - simply use longer electrodes (another advantage of using
rerod). you may also need to use MORE electrodes with larger parts and a larger "tank".
to Bill's Greasy, Rusty, Humdinger Page
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Last Updated on September 5, 1998 by Bill Dickerson
I used a battery charger for electrolysis extensively last fall when restoring my 6 hp Fairbanks, the results were great. I used a plastic mortar mixing tray that was 24" x36" by about 10" deep for doing the sub-base. It wasn't deep enough to submerge the whole thing, so I had to flip it once to get the top. I don't know if it makes a difference or not but I tried to keep my container just a little bigger than what I was cleaning. For the head I used a 5 gal mop bucket.
I have a charger that does up to 15 amps in charge mode and has a 100 amp boost for starting. With it set for 15 amps I was able to pull between 9 and 12 amps most of the time, I think the dirtier the solution got the less the current flowed. Sometimes when getting it started I would bump it up to 100 amps for 30 seconds, just to get things "boiling" and then would knock it back down to 15 to let run overnight.
I used the instructions from Bill's page, I printed them out and stapled them to my garage wall so I could refer to them every time I hooked something up to make sure I got it right. His instructions use re-enforcing rods for the waste electrodes, on the larger stuff I used old lawn mower blades, which worked beautifully. I love using this method, I got things just as clean as sandblasting did for my flywheels (I did not want to remove them from the crank) and it was cheaper. I have plans to use this method again on some 28" steel wheels I am going to use for a cart, I just need to find a big enough bucket.
If you reverse your leads from your charger and change the rerod to nickel or some other nice metal, you can electroplate your parts. Use clean water!
This is a well known rust removal method- I've used it with Red Devil lye as the electrolyte.
Some of you may recall The "Redistrip" commercial process, which handles even entire auto bodies. I carted all my T's sheet metal up to Tampa, FL for a Redistrip treatment- overnight, the sheet metal was returned to me entirely rust free. The process is entirely non-destructive to good metal. However, the hydrogen bubbles do introduce "hydrogen embrittlement" to hardened/tempered items.
Remember when hooking up that the "red" (positive) will rust. The items come out of the bath clean except for a black film you simply rinse off.
Plain lye works very well. The lye or soda is merely an electrolyte- it has no direct action on steel. In fact, any alkaline such as lye or washing soda actually prevents rust. You could store delicate steel parts in lye water forever- there will be no deterioration of the steel.
The stronger the concentration of electrolyte, the more conductive the solution. A battery charger provides a safe source of amperage at low voltage. If the solution is strong, the current density increases. I would start with a weak lye water solution first, stirring in more lye until the amperage increases to a comfortable rate for the charger. A low current density works just as well- but more slowly. A weak (er) lye solution is less risky to human skin. A wash soda solution is safer yet. I have no used washing soda- but no doubt, it will work.
As the action progresses, the anode ("red" or positive) material becomes encrusted with rust, and the current density will taper off.
As for weakening critical parts? Corrosion removed leaves pits and stress risers that are present even though filled with rust. I don't see a problem with removing rust from stressed parts- but if they are damaged by rust they remain damaged and weaker.
Springs and gears, ball bearings, etc are hardened to some degree and would require baking after rust removal to drive out the hydrogen.
The process works- and works well, but is not very effective in shielded areas like water jackets. Immerse only ferrous metals-the alkali process tends to eat up babbit, brass, zinc and even harm bronzes.
I've always used Arm & Hammer Laundry detergent, seems to have enough baking soda in it. I keep a 55 gallon plastic drum out in the old corn crib. Did a tractor hood last summer, came out real nice. Make sure you use a battery charger with a gauge on it, you can tell if it's working or not. You want about 10 amps showing. I put in about 5 - 10 cups of soap and it lasts all summer.