molasses as a rust remover

[gwilcox217]

I'm new to this forum but thought I'd share a recent experience with rust removal from my AA gas tank. It sat for three years and when I went to change the tank valve some pretty nasty old fuel came out along with rust. Inside inspection revealed a fair amount of rust inside. I removed the tank, but not wanting to send it out to be acid washed I heard molasses is a chealating agent and mixed with water will in time remove rust. I purchased a 2 1/2 gallon jug of feed grade molasses,( $14.95) mixed it with 7 1/2 gallons warm water, filled the tank. Left a droplight under the tank for warmth in my garage, covered it with a blanket to insulate and waited two weeks. Drained it, rinsed with plenty of water and wow it really did! Hit it with a quick etch treatment then sealer . Pretty cool!

[carnut14]

I've heard of molassas removing rust. But usualy it was someone who knew someone who had a neighbor who tried it. Nice to meet someone who has first had success. Thanks for posting

[Chris Haynes]

I have used it many times. But you must use horse feed grade molasses. The stuff from your grocery store won't cut it.
For smaller de-rusting jobs soaking parts in WHITE Vinegar works well in just a day or two.

[Warpspeed]

I have never tried molasses, but I have tried quite a few other methods, most of which did not work very well, or not work at all.

Many of these methods simply aggressively attack and dissolve the rust o/k, but leave the remaining steel pitted and vulnerable to very quickly re rusting.

This following method I have used for many years very successfully.
It not only REVERSES the rusting process, but leaves the steel or iron part in a condition that discourages further rusting.
It's not my idea, but full credit to Dan of Southern California, a Hot Rodder that originally posted it on the internet.

Remove Rust and Scale from Steel
I want to give you people a tip or technique I have used for may years on the repair of iron based parts. This is not practical for 99.9% of you but the technique can be used on a smaller scale on any steel based part.
Rust can be safely removed off of STEEL parts by converting the rust itself, i.e. FeO2 and Fe2O3. Rust, hydrated iron, can be chemically "reduced", that means converted from a bonded molecule to a simple molecular Fe with free disassociated floating anions, by attacking the rust molecule with a charged molecule of something that likes bonding better than Fe. For this case Zinc works great.
How is this done, chemical reactions of this nature generally work faster with higher temperatures, a fluid bath is needed to better transport the replacement molecule to target areas. The Zinc must be turned into molecular Zinc and electrically charged to go after the rust and replace the Fe molecule with itself.
Now that is the theory so how do we get there?? Iron is pretty much impervious to alkaline solutions but dissolves im most acids. Zinc will dissolve in just about anything. We make up a solution of lye and water at the ratio such that the water will boil at approximately 270F well above the normal 212F. Toss in some Zinc, preferably Zinc Oxide or just dirty Zinc. The Zn dissolves into the NaOh (lye) and leaves the Zn now charged positive. Since Zinc likes to bond to things better than Iron (Fe) the Zn+ molecule attacks the rust and takes the Iron molecule off and bonds itself to the Oxygen molecules that made up the rust. BUT in doing so it winds up floating in the solution. The result, the rust gets stripped off the Iron part, the Iron itself is untouched. This type of process has absolutely no bad effects to the original part just to the rust on the part. If you were to try an acid dip it would attack the base metal itself, the iron part.
I have used this process for about 15 years on everything from a cast iron Ford Model "B" carburetor body to antique guns of the worst state. Two years ago I boiled an entire circa 1909 Ford Model "T" open valve engine long block. It had sat in the rain for probably some 40 years. Took a while to get it apart but when through there was no rust anywhere. I prepped a Model "C" block this way a while back. However for something of this scale I had to convert a 50 gallon steel drum for the boiling tank and lowered the engine down in on a chain fall. For heat I used an old diesel fired hand pump weed sprayer type of "weed burner", something you guys probably never saw lest you lived on a ranch.
The basic principle can be applied to just about any iron part.
But in the case here of stuck valves, why not try and have the block cooked at the 800F and just see if that will knock the parts loose. Won't cost that much and it might just do it.
I have used this process on a lot of stuff. Most of it is done in a large 3 pound size of coffee can that just fits on a small element on my electric stove. Also handy is a cheap used Coleman camp stove in case you are married and your wife does not approve of what you are doing. Fortunately I am single with a very pretty, younger and understanding "friend". She puts up with my weird experiments and just gives me that "look".
This works great for cleaning up the base plates for 94's and 97's.
The next trick in using this is as follows;
Hang the part on a piece of steel wire in the solution so you can pull it out from time to time and check it. I use safety wire for bolt heads. When the parts are done rinse them under lots of COLD running water. Next I immediately drop the parts into a solution of oily gasoline or thoroughly spray down with WD-40 to displace any water on the surface, some times then heat the part on a tin can lid (lid from the coffee can) to warm the part and drive off any remaining water in the pours of the metal, helps drive the oil into the surface as a preservative effect.
Cool trick of this process is that the lye being alkaline it treats the micro surface of the part and inhibits rust formation on a raw metal surface. If you try to acid dip a part it will always leave micro deposits of acid in the pours of the metal and it will re-rust in a matter of days. In an alkaline process this will never happen. If you see a gray smut form on the surface that is the carbon found in steel, part of the manufacturing process to make steel out of iron. Carbon is inert to these solutions so when the rust is dissolved into the solution it leaves behind the contained carbon. Just wash if off, I often use a tooth brush.
Dan So Cal


http://www.btc-bci.com/~billben /rust.htm

The link no longer works, but fortunately I saved this priceless wisdom.
Thanks Dan.

[spectria]

I have never tried molasses, but I have tried quite a few other methods, most of which did not work very well, or not work at all....

...The basic principle can be applied to just about any iron part.
But in the case here of stuck valves, why not try and have the block cooked at the 800F and just see if that will knock the parts loose. Won't cost that much and it might just do it...

A very interesting method! (Is that a typo I have highlighted?)

[Warpspeed]

A very interesting method! (Is that a typo I have highlighted?)

I have absolutely no idea !
I just copied and pasted the entire article as I had saved it a few yeas back.
Sounds pretty drastic.

The Lye + zinc + heat method definitely works.
It also works without heat, but it takes weeks not hours to have the same effect.
That same brew also eats paint and grease with ease.
Just make sure there are no copper, brass, or aluminium bits put in there, because they are going to disappear.

[pyrodork]

you could also use a retired crock pot instead of a pot on the stove. that's what i've done.

[Warpspeed]

I just succeeded in finding the original article by Googling the first sentence.
It still says 800 F.
But for the normal recommended de rusting process, you don't need anything like that.
150F, 200F, 250F all work fine, higher temp just makes it work faster.
I have used everything from a stainless steel saucepan on the kitchen stove, to 50 gallon steel drum and large propane burner.

http://www.btc-bci.com/~billben/rust.htm

A fuel tank might be rather difficult with this method.
The original molasses idea sounds much more appropriate for a fuel tank.

[spectria]

No liquid would remain liquid at 800f. This must be a typo.

[Warpspeed]

No liquid would remain liquid at 800f. This must be a typo.

What he is talking about is heating an engine block in an oven to release stuck and rusted in side valves.
There is no liquid involved.
A bit like heating a badly rusted nut with an oxy acetylene torch.
It has nothing at all directly to do with the de rusting method.
If you can imagine saving an AA engine that has been maybe buried underground for fifty years, getting the valves out may be a bit of a problem that goes beyond just de rusting the block.

At least that is how I read it.

[spectria]

No liquid would remain liquid at 800f. This must be a typo.

What he is talking about is heating an engine block in an oven to release stuck and rusted in side valves.
There is no liquid involved.
A bit like heating a badly rusted nut with an oxy acetylene torch.
It has nothing at all directly to do with the de rusting method.
If you can imagine saving an AA engine that has been maybe buried underground for fifty years, getting the valves out may be a bit of a problem that goes beyond just de rusting the block.

At least that is how I read it.

Yes, I Agree

[fordman88]

got a couple of questions about this...

would the above method work better than the baking soda+water+battery charger? i read and tried out the idea with the battery charger about a month ago on an old windshield frame a had and it worked very well! i was impressed and excited at how well it worked. took a little time on the badly rusted areas but still. i just recently found a 150 gallon plastic tank to use for this so i can do bigger parts.

if it does work better, I'm thinking it would be a much faster alternative for parts such as engines and axle housings... from what i can tell. the battery charger method would take a month to clean a heavily rusted part!! hahaha

second question is, how would the zinc dissolve in the solution?? is it because the solution with the lye is corrosive and eats away the zinc? or is it because of how hot the solution is?? i love experimenting, and my girlfriend is pretty understanding of my "nerd-ness", im thinking i might have to give this a try later!

[Warpspeed]

The zinc seems to pretty much dissolve in the Lye until the solution is saturated with zinc.
Adding further zinc shavings, they just sit at the bottom of the tank and appear to do nothing.
It doesn't take a lot of zinc to do this.

All the other chemical and electrical methods I have tried seem to strip off the rust, but the Lye method converts the rust back into iron/steel and it inhibits further rusting once the process is finished.

I have tried the washing soda + battery method, rust seems to keep coming off the part for as long as you leave it in there. I have a nasty feeling that if you left a part in there for a very very long time there may be nothing left to remove.
I have had some of this strong lye solution stored in a 50 gallon steel drum now for several years, with absolutely no damage to the steel drum.

That is the incredible thing, it is completely harmless to ferrous parts, but really goes for paint, grease and rust.