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CLEANING OF CASE HARDENED STEEL

CAN I USE 1 PART SULFURIC ACID TO2 PARTS WATER? I PLAN TO USE THIS MIXTURE, LEAVE PARTS IN FOR 3 MINUTES AND THEN PLACED IN A RINSE OF SODA SOLUTION IMMEDIATELY TO STOP THE REACTION OF THE SULFURIC ACID. DO ANY OF YOU SEE A PROBLEM WITH THIS PROCEDURE AND IF I'M WRONG COULD I GET SOME HELP FROM YOU?

THANK YOU FOR YOUR HELP.

PAM DOVER
BUYER AND REGULATOR - ANNISTON, Alabama, USA
September 10, 2009

Hi, Pam. Sulfuric acid is not a cleaner. Most cleaners are alkaline not acidic. You also introduce the possibility of hydrogen embrittlement.

Generally, shops who do metal finishing do not try to go it on their own, making up the process from raw chemicals. Rather, you will find that there are metal finishing process suppliers who will assist you in choosing their products and developing a process sequence. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 11, 2009

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First of two simultaneous responses --

It would probably help to know what you are trying to clean off the steel. Some case hardening leaves nice pretty colors behind when the process is complete. It is common on firearms and some high dollar knives and tools. I have also seen it used on the housings of antique and replica clocks and barometers.
I know for a fact that any acid, even vinegar [in bulk on eBay or Amazon] and most soft drinks and fruit juices will strip off this color. I guess if you are trying to remove old grease and grime, varsol or any other good solvent will work.
I some times find rust on color case hardened gun parts. I use light sewing machine oil and #0000 steel wool [on eBay or Amazon] to remove it. When I do this I am very careful as too much pressure will remove the color.

Rod Henrickson
gunsmith - Edmonton, Alberta, Canada
September 12, 2009

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Second of two simultaneous responses -- September 14, 2009

dear sir,

go for sand blasting to remove scales after case hardening. any acids used will react on metal surface and will corrode and also not a safety measure. the acid fumes will be in the atmosphere and also it will spoil your other good components also,

with warm regards,

B. Manickavelu
- Bangalore, India