Need help with finishes on C96

[DonVoigt]

Originally Posted by alvin

I have never done things like this before. From youtube.com video, midwayusa showed how -- the nitre blue salt is a pink color solid stuff, he put the salt into a pan and "cook" it. The salt melted. Then, he dipped small parts into the melted salt, the metal color changed, then he took it out. That's it.

He did not explain the theory. Here is my guess -- that salt melts around 600F. So it's just temperature control media. This is obviously more controllable than using a torch to create fire blue on small parts -- using torch, you have no control on temperature, using this type of salt, it's much easier to control, and the metal is heated much more uniformly. Unlike regular bluing process, I don't think there is a chemical reaction between the nitre salt and metal. Just a guess.

Here is the video:

https://www.youtube.com/watch?v=-vF3zKiUIkY

Alvin
What you describe is Not typical hot salt bluing. Which is a chemical reaction, not just heat. Salts consist of sodium hydroxide and sodium nitrate, and each contains some crystalized water.

Tempreature is controlled by adding back water as it boils off, or the temprature will increase as time goes by.

It is a hazardous and corrosive mixture, rubber gloves, rubber apron, face mask, etc are recommended as the salts will splash.

You will corrode your stove and vent if you do it much!

Salt bluing is best left to an expert with the proper set up and know how.

It is not a do it in the kitchen operation.

Metal preparation is the most important step, followed by degreasing before putting into the salt.

Poor prep = poor results.

What is shown in the video is the same as what the others are describing using the oven or hot sand in the oven, he is using a salt bath to
control the temperature to 600 degrees+/- to achieve the pretty blue. It is heat treating as Ollie has described.