Molasses Destroyed Piston Pin Chrome Finish

-

dibbons

Well-Known Member
Joined
Nov 6, 2009
Messages
6,007
Reaction score
4,077
Location
La Paz, B.C.S., Mexico
My experimenting with the molasses/water mix for rust removal kind of backfired on me. The piston pin was not rusty, but I dropped it in the mix along with the matching connecting rod. it came out Navy Grey in color with hardly any sign of the chrome left (center pin in foto).

DSC04108.JPG
 
Did the molasses do the trick on the rusty rods?
How much water to molasses and how much time?
Did you have to stir it occasionally?
I want to give it a trial on a rusty oil pan after this cold weather passes,

There is a flash chrome put on valve stems, pretty thin, then polished out even thinner, I don’t think I ever remember seeing piston pins chrome plated,, the steel piston pin is ground and polished to an extent that it is very round, very smooth and very shiny, but not plated.
 
Last edited:
Very interesting....
molasses 1,chrome 0.
Wonder if it will pull chrome off bumpers?
 
I don’t think that piston pins are actually chrome plated. I believe they are polished steel (possibly chromium based). If I’m correct about that I can see the molasses being caustic enough to etch the polished surface. But I’m no expert so someone will come along more knowledgable than I.
 
Last edited:
The ratio was about 10 parts water to one part molasses. I lost track how long it was in there for at least two days, probably three or more. I did not stir it up after the initial mix (using warm water). It does remove rust.

I won't use them again, but since I already have a 55 gallon barrel mixed up (my cylinder block and heads were in there previously) I am planning on dumping some rusty valve covers and rusty oil pan in the mix just for kicks.
 
Last edited:
Some aren't polished and are just lapped into size. See if you can't determine a very fine grain pattern going around the OD on a clean one.
I can't remember a standard plating operation on any at BN but that was years ago.
I know some show parts were chromed.

 
Last edited:
Some aren't polished and are just lapped into size. See if you can't determine a very fine grain pattern going around the OD on a clean one.
I can't remember a standard plating operation on any at BN but that was years ago.
I know some show parts were chromed.


We’re you at the Burgess Norton plant in Geneva IL
 
Pins are NOT chrome plated. That would be bad.

Any chance you could Mic it and see how much metal was removed?
 
Product Information - Piston Pins

Perhaps it reacted to the chromium in the pin at the surface only.....
Daves69, I was a Engineer for one of your customers, BN Geniva was an older facility, but had pretty good people, machinery and processes, the stuff that I worked on was moved by BN to the new plant in Mexico, I hated to see it get relocated.
 

Put them on a buffer with some red rouge compound and they will likely polish up.
 
I don't think that difference is significant in the least. That could be the difference between one being colder than the other. I think maybe the goop just turned it dull.
 
Daves69, I was a Engineer for one of your customers, BN Geniva...........
Started there in '76 at about $2.70 an hour. I did about 4 years at the pin plant down town in various positions before going across town to the PM division. They sent a lot of work to Claremore, OK prior to opening up Mexico.
 
This spring, I am going to dip a whole 340 block in molasses if I can find a plastic barrel cheap enough.
It is rusty, so we will see how it cleans up.
 
This spring, I am going to dip a whole 340 block in molasses if I can find a plastic barrel cheap enough.
It is rusty, so we will see how it cleans up.
Give it a couple weeks and pull it, wash it off and see how its goes...
 
I am in no hurry for it, the block is just an extra I might use one day.
 
-
Back
Top Bottom