Forcing Patina on 3V

[Big Chris]

Have any of you ever forced a patina on 3V? I have had a blade sitting in vinegar for almost five hours now and there is no color change. Am I doing something wrong, do I have the wrong vinegar(I just got some off the shelf at Meijer). I knew it would resist the patina some, but thought for sure I would have some color change by now.

What are some of your thoughts?

Thanks
Chris

 

[Justin King]

I had trouble getting it to etch in vinegar, ferric chloride works much better. It sometimes helps to etch, then scrub it down with degreased steel wool and etch again, but vinegar might not be strong enough regardless.

 

[Stacy E. Apelt - Bladesmith]

Etching is a chemical reaction. Things that speed up the action are:
Heat - warm the solution .
Strength - use stronger solutions. White vinegar is often stronger and purer than cider vinegar.
Purity - If the solution is contaminated with other things, of exhausted for previous use, it needs to be changed.
Type- Some things work better than others. Muriatic acid will etch the he!! out of stainless , while vinegar barely etches some steels. FC is in the middle. Varying the concentration of acids and FC is the best way to get an even etch.
Resist - If something is blocking the etchant from reacting with the steel, it is called a resist. It can be grease, dirt and oil from you fingers; Residue from grinding;Laying against the tank bottom/side; or a build up of oxides on the surface. This is why a blade mush be freshly sanded , cleaned immaculately, and suspended in the center of the etchant for an even etch.

 

[S.Knowles]

Just as Justin said, I've had best results with Fecl.

Shawn

 

[james terrio]

I've gotten a nice light grey finish on 3V with plain white household vinegar at room temperature, but it takes at least 24 hours. You can heat vinegar to boiling and naturally it will work faster, but good golly your spouse/kids/dogs whatever will be mad if you do it in the kitchen