Types of solder that will blue?

[Virginia Gentleman]

Is there a source that makes a solder that will blue if rust blued?  I need to solder in a front sight of a gun that will be rust blued.

[Kent Shootwell]

I don't believe any solder will blue. The trick with solder is to use very little in a well fitted joint. I've done a fair amount of sliver soldering of gun parts and a small bit of it will hold a lot if the parts fit close. The solder that shows doesn't add strength so a hair line of solder at the joint is a plenty, none showing but 100% under the part is best.

[Virginia Gentleman]

Brownell's sells some that it claims will blue and I will call them to see which one will work best on a SAA front sight.

[Montana Slim]

I'm not aware of any solders that blue (black oxide) either. Factory finish process uses a dunk tank in the process to chemically dye the solder a black color. Still, if you look close, you'll be able to see the slight color difference.

Regards,
Slim

Edit to add.....the "blue" compatibility claim of the solder may simply be that it resists attack from the chemicals in commercial bluing salts.