Tool steel turning black

[Dundee]

After a few hours of use the shaft of the gouge where my hand grips it is turning black. It doesnt wipe off like its just dirt from my hands. I have to polish it off with my strope compound. Is this from acid in my sweat? Should I shellac the upper parts of the gouge to protect it?

Thanks
Chris

[Jim OH]

Hey Chris, maybe ya better wear two carving gloves ) Haven't had that problem so not sure about any other advice.
Jim OH

[AlArchie]

There are several amino acids in normal sweat and some may promote reactions with some sulphur compounds (disulphides*), also present in sweat, and the structural protiens found in fingernails. Mild sulpheric acid can react with steel to form a black iron oxide (Fe3 O4) . This black oxide is actually a protectorant layer and will inhibit that red rust you normally get. I'd leave this black oxide alone...maybe a wipe with light machine oil.

Henry Taylor tools come with a blackened shank...not painted, but chemically blackened to prevent rusting.

*The sulfur atom binds readily to heavy metal ions. Under oxidizing conditions, two cysteines can join together in a disulfide bond to form the amino acid cystine. When cystines are part of a protein, insulin for example, this stabilises tertiary structure and makes the protein more resistant to denaturation; disulphide bridges are therefore common in proteins that have to function in harsh environments including digestive enzymes (e.g., pepsin and chymotrypsin) and structural proteins (e.g., keratin). Disulphides are also found in peptides too small to hold a stable shape on their own (eg. insulin).

And ya, I had to look this up, but I seemed to remember something from dealing with tool steels about coloring from different acids. If we've got a metalurgist or chemist on board, maybe they can give a better explanation.....I won't claim to be either, and this is just my best guess.

Al

[Hi_Ho_Sliver]

I had an old friend that was a diebetic and the same happened to him, anytime he touched metal it left fingerprints....I mean black ones, not the normal fingerprint

[Dundee]

His diabeties wasn't the cause I hope. I don't have diabeties that I know of. These are Pfeil tools if that has any bering.

Thanks
Chris

Originally Posted by Hi_Ho_Sliver

I had an old friend that was a diebetic and the same happened to him, anytime he touched metal it left fingerprints....I mean black ones, not the normal fingerprint

[Hi_Ho_Sliver]

I don't know, he always said it was.....I was recently diagnosed with type II but don't have that problem....no doubt some acidic thing in the skin?

[Lynn O. Doughty]

I wouldn't really worry about it. Might actually protect the metal from rust. One thing for sure, if you buff it off you might remove any protective coating applied by the facgtory and then it WILL rust!

[BasketballJones]

It has to do with the acidity and alkalinity of your skin and the oxidation. Chemicals in your skin and sweat counteract with the metal, fabric or anything touching the skin. It's common with folks wearing silver jewlery, metals with nickel, and brass and copper. I can turn a doorknob black when sweaty. Clean up your tools and hands with rubbing alcohol. I use handwash cleaner for the hands. Check you shirts I'll bet you got ring around the collar. If you have a silver band watch I'll bet it's black underneath. I turn the fingers of my white golf gloves black. Certain colognes work better than others and make us smell sweeter than othersTalking . Your fine.

[Hi_Ho_Sliver]

Sweeter than other what?

[Thomp]

take your tools to a gun smith and have them Parkerized... at least they will be all the same color.

check out this link on wikipedia Parkerizing if your worried about the tools being ugly looking, maybe a solution, but i dont think it can be done with handles on.