phosphoric acid rust removal field test

Did you ohm the stator before you dunked it? If it was good, I think you might have been better off leaving it alone. I am not an expert, but I have heard that old stators (and rotors) should be disturbed as little as possible, in particular you should not touch the shellac on the windings. So, be careful wiping and drying when you finish.
 
Last edited:
oh man if that is shellac I am probably screwed and created a fancy (but clean) paperweight out of a possibly good stator.

I guess i'll test it out in a few
 
I saw that gas cap before, and the change is impressive. If there really is something about this molasses method that leaves a coating that prevents flash rust, then I will be completely sold on it.
 
Well sgallaty you are on something of an "electrolytic roll".... so to speak. As to some of the hypothesis about what's going on with various interactions of between phosphorus, iron and aluminum ions do remember that you've introduced several more metals than just those three to the mix plus a large variety of states of oxidative products. Those reactions and reductions will take place somewhat in order of the electrolytic order of metals and compounds present. All of which will be driven by having an excess of the reducing agent available. Many of those oxides are also gray and black and the "soup" is itself getting highly muddled. Now...you've got a lot of copper in the game too....Hello copper complexes and you will soon need a phd and a mass spectro-photometer to say nothing of a complete inorganic analytical chem lab.....and one helluva lot more molasses. As you say and that's just the inorganic chemical portion. What about the cow shit? Mind boggling.......

Damn.....glad I'm retired! Best, Blue

Another matter....removing the loose by products of the reductive reactions from the pot/mix
will also drive the ongoing reduction process; just as will maintaining an excess of reductive phosphoric acid reactant. Those reactions are always working in both directions you'll recall.
 
DogBunny said:
I saw that gas cap before, and the change is impressive. If there really is something about this molasses method that leaves a coating that prevents flash rust, then I will be completely sold on it.
Click to expand...

It's usually good to neutralize the cleaned surfaces involved and give the clean metals an oil coating unless you're going to paint or otherwise coat. In those cases many good primers take well to phosphate etchants for adhesion and in fact many primers themselves are phosphate coatings....zinc phosphate for example and or copper, nickel, chrome cadmium eg.

Less we get too enamored of the "molasses" per se, let's do remember that it is essentially serving as the phosphoric acid 'delivery truck' and it could well be bringing Coca-Cola or even Ragu Sphaghetti sauce or lots of other foods or drinks.

Too bad Dupont used it already....Better Living Through Chemistry Best, Blue
 
I dunno, I'm pretty enamored right now.

Effective, non toxic and inexpensive.

I would like to have a way to remove the particulates, but alas.
 
7/19

Aluminum is cleaning nicely, the heavy rust in the cylinder is slowly deteriorating.

I find that the bulk of the reaction spectrum is exothermic. Most of the examples I've seen have shown the vat that the pieces were dunked in being outside, in summer so I would guess (without any measurements) that the solution was between 90-100 degrees.

I found that at 75 degrees the observable reaction was considerably slower, based on the generation of gasses and the effect on the pieces.

I've set the solution outside in direct sun to excite it.
 
bluebikerblan said:
Grepper....You are just plain wrong regarding your information about "Muriatic Acid",
as are your recommendations regarding it's proper use and the chemistry involved.

http://hubpages.com/hub/What-is-Muriatic-Acid

Muriatic acid in fact has nothing to do with phosphoric acid diluted or otherwise.

It is dangerous and hazardous to use Muriatic Acid as you suggest... period... and should be completely disavowed! Blue
Click to expand...
Muriatic acid is hydrochloric acid, diluted about 30% (not certain but an MSDS will tell you for sure) - as such it is indeed very dangerous and should only be used with rubber gloves and good ventilation - vaporous hydrogen chloride can be give off and if inhaled can cause permanent lung damage - scar tissue, etc. It is a very good cleaner tho.
 
sgallaty said:
I bought a siezed engine from a friend that ended up having a great deal of rust in one cylinder and a ring in the other.

I'd read different derusting methods and there was only one that appealed to me which was phosphoric acid rust removal.

The method is to create phosphoric acid with a 9:1 ratio of molasses to water, and then submerge the piece in the solution.

It is also available in larger concentrations commercially. http://www.42gpw.com/acid.html

--

Experiment -

The experimental piece is a set of cylinders which significant rust on one cylinder and light surface rust on both.

Method -

Submersion in a solution of 9parts water to 1 part molasses, combined with nonabrasive physical debris removal and solution agitation.

Chronological Diary

Started experiment on 7/12. Created solution and immersed head.

Observations :

even after rinsing, the head had a great deal of foreign material and oils adhering to it. This caused pollution of the solution.

solution did not begin to react for approx 12 hours after immersion. did not test, but suspect that the phosphoric acid is not formed immediately.

It has a moderately unpleasant odor

Notes :

For the next experiment, we'll soda blast to thoroughly clean all parts prior to immersion.

for best results, solution should be premixed 24 hours prior to immersion.

when process is underway, bubbles (presumably oxygen from the FeO Iron Oxide breaking down and the formation of FeP2/FeP3 Ferrous Phosphate.

Condition of piece on 7/12
Click to expand...
hydrogen gas perhaps? just sayin'
 
I dilute it when using it on sheetmetal as an etch. When I use it to drop parts in, I do not. I have bought it was my paint supply, from Home Depot and from auto flea markets. Its everywhere.
 
I may try it in higher concentration to see if that works differently. I wasn't familiar with it until I read about removing rust with molasses water which sounded absurd, so I set up this experiment.

Here's another piece I am doing for dogbunny, he has a few of these.

I didn't think to take a picture when he gave these to me, so this is actually after an hour in the soak, hence the blackening.

rusted_part_frombill_1.jpg


rusted_part_frombill_2.jpg
 
I recently bought a '57 Sportster tank which was very rusty inside. I left Phosphoric Acid in it for about 6 days. I flipped the tank around to get all sides well. After I poured it out and rinsed it, it was much better, but not clean. I poured in some Master Series, , moved it all around for coverage and its good to go now. Master Series is impervious to gasoline.
 
My wife has demanded that I put on here that it stinks. She says that it used to smell like a dirty butt (she changes the diapers), however now she says it smells like vomit.

Here's some before and after pictures. Note that I have not used any abrasives, not even a plastic brush on these parts.

The cylinder heads :
BEFORE :
trash_bike_cylinderhead1.jpg

trash_bike_cylinderhead2.jpg


AFTER:
trash_bike_cylinderhead_after.jpg.jpg


rusted_part_frombill_after.jpg
 
PetesPonies said:
I dilute it when using it on sheetmetal as an etch. When I use it to drop parts in, I do not. I have bought it was my paint supply, from Home Depot and from auto flea markets. Its everywhere.
Click to expand...

When you purchase your Phosphoric Acid... what name is it sold under? I've been asking around and most people just look at me with that puzzled look on their face! We have Home Depot, Lowes, McClendon's, ACE, etc... I'd like to get some, but can't seem to find it.

I am soaking my 79 XS650 Special II tank with Evaporust right now... It's been in there about 24-hours now, and frankly, I'm not sure it's doing much good... The neck did get clean, but the rest of the tank seems iffy... I've been rotating it around about every 3-hours or so to make sure I'm hitting all parts of the tank. Only have a gallon of the stuff in there, however. At $22.00 a gallon, I'm not sure it was the best way to go at this point. Hopefully when I inspect it tonight, I'll think otherwise.
 
Home Depot doesn't sell what they used to sell :( I went and looked for what I had bought in the past. They do have this
http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053

DuPont has a metal etch that I buy and its phosphoric acid. You can get it at auto paint supply houses.

You may also look for Jasco prep and prime. And one last thought . at auto flea markets, look for someone selling rust remover that is a dark green. Thats phosphoric acid.

And just found this on their site:
http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053
 
Darin, Give it time, rust is obviously oxidized metal and it takes time to strip the oxygen atom off, you can increase the speed of the reaction by putting it in a warm place. If you do that you will need to watch it closely as funny things can start to happen with the raw metal, shouldn't be an issue though. The product is a "safe" rust remover so give it time.
 

Similar threads

jetmechmarty
Phosphoric acid for rust on chrome parts
2 3
Replies
57
Views
8K
OHRider
OHRider
Back
Top