What is the best rust remover soak?

Joe K said:
I have done a Model A engine block. I have heard warnings that electrolysis can "loosen" the bond of babbitt in the engine block. I can't say I saw a sensible loosening, but the babbitt appeared "dull" in appearance, much like the cast iron machined surfaces tend to look. That engine was headed for a re-babbitting anyway.

This summer's project was a couple of Model A wheels, heavily rusted (paint all gone) A bit rough but paint will fill in the pits somewhat. For this I built a wooden box about 2' square and 12" deep, and lined it with a sheet of 6 mil plastic. Folding the interior corners of the plastic brought to mind my military experience of "hospital corners" - in reverse. "Line of sight" on those wheels. They were flipped at least four times per wheel.

Electrolysis WILL loosen rusted together pieces. My most heavily rusted together parts ALWAYS head into the bath first for a couple of days prior to PB Blaster, heat, or armstrong loosening.

Electrolysis did a nice job on the interior pumps and parts of the Monitor Civil War battleship. Larger parts of which have been recovered and are now being conserved.

https://sanctuaries.noaa.gov/news/aug16/restoring-the-turret-of-the-uss-monitor.html

Joe K[/

I’ve never done a babbit block in electrolysis, only Flathead 8s. I’m interested in learning more about babbit bearings and electrolysis though.
Click to expand...
 
I’ve never done a babbit block in electrolysis, only Flathead 8s. I’m interested in learning more about babbit bearings and electrolysis though.
Click to expand...
As I said, I'm not sure my electrolysis made any appreciable difference to the babbitt other than surface appearance. They didn't appear loose, and even if they did one imagines one could "pein" the babbitts back into full contact with the block. Many blocks are "tinned" as a way to make the babbitt "adhere" to the block - but many are not. I'm not sure that Ford even took the time relying instead on the post-pour "peining" to achieve that full contact (The babbitt by necessity has a tendency to "shrink" away from the block as it cools. )

Tinning the block beforehand is supposed to prevent that - but tinning ANYTHING in cast iron is fraught with challenge.

More important for electrolysis on babbitt may be "honeycombing" the babbitt - that may be the origin of the "change of appearance" mentioned.

Babbitt as it exists in the poured/solidified state is a "matrix" of composition, with the majority being "tin" (88 percent) "Antimony" (8 percent) and Copper (4 percent) Actual assay may vary and Ford had his own formula IIRC.

Of those three elements, one finds the electrochemistry tables puts all of these at "different" levels, with Sb (Tin) at "most reactive" of the three. See https://chem.libretexts.org/Ancillary_Materials/Reference/Reference_Tables/Electrochemistry_Tables/P3%3A_Activity_Series_of_Metals

In a way, the Tin becomes the "sacrificial anode" of the combination (thinking back to my "marine" experiences.") Not to say that there was even any visible degradation of the babbitt as a functional entity.

So I can't really answer your question properly - but it's something to think about/be aware of.


Joe K
 
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I’ve had electrolysis work ok in a 5 gal bucket. Tried 40 gal for bigger stuff…..not so great.
All in all, I give electrolysis B- but could be me! Followed all instructions and YouTube.
Dunno
 
Just curious - what do you guys think about using a rust remover on something like a carburetor? Would it cause more problems than it could fix?
 
I used citric acid in a big plastic livestock watering tank. I bought 5 gal of citric acid and it’s mixed @10-1 mixture it soaked for a week or so and then pressure washed the part, I had great success. I applied phosphoric acid to keep it rust free. The problem you have to dismantle the body.
 
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