Bluing case-hardened steel

[wixedmords]

Anyone have any tips for bluing case-hardened steel.

I have a cylinder stop stud I like to take a shot at bluing.

Thank you.

 

[WOB]

Rust blue works on case hardened steel.

Cold blue like Brownells Oxpho-Blue might work. Try acid washing the stud in 50-50 Muriatic acid - water solution if the normal cold blue procedure doesn't work. A 30 sec. dip should clean off the surface well enough for the cold blue to work.

WOB

 

[wixedmords]

Thank you WOB.

I've been the route of sandpaper and steel wool on the stud and cleaned it with alcohol and vinegar. Nothing seems to help the blue stick.

I'll give muriatic acid a shot.

 

[I_Like_Pie]

I have had similar problems with some S&W parts. Seems no matter what I tried it would not take. tried 290, 300, 310 degrees....nothing. Different pre treatments - sanding, blasting...nothing.

Because it was a small piece I just ended up nitre bluing it with molten saltpeter I got from stump remover at Home Depot. It was the 100% potassium nitrate kind. Had to get it around 600 degrees.

It worked, but was a royal pain and I wouldn't attempt on anything larger than your thumb or something that was heat treated.

Look up nitre bluing...it works, but is on the more obscure end of finishing as it really isn't used that much any more.

 

[wixedmords]

Thank you ILP,

I have been watching some vids on the nitre bluing process.

It sounds like your experience worked well for you.

All the responses are appreciated.