Bluing with linseed oil

[Suzuki4evr]

Hi guys.

I wanted heat blue some parts with linseed oil. What is recommended, boiled or raw linseed oil in your opinions?

Thank you
Michael

 

[deadwood83]

My vote goes to raw. Boiled has numerous metallic driers and other nasties that may not do your lungs a favor when vaporized/heated. You can find raw at your local vitamin supplier labeled as "flaxseed oil" for way less than cold-pressed artist-grade blah blah blah as well.

 

[WCraig]

Keep in mind spontaneous combustion. Linseed oil-soaked rags can and do start fires if not properly handled.

Linseed Oil and Spontaneous Combustion: Take it seriously. | Popular Woodworking

The danger of linseed oil rags spontaneously combusting is not new in the woodworking world. But because so many woodworkers use wipe-on stains and finishes that contain linseed oil, the warning can’t be repeated enough.

www.popularwoodworking.com

Also, AIUI, almost any oil--even used motor oil--will impart a dark colour to heated parts. I'm not sure there is any advantage to linseed.

Craig

 

[Video_man]

FWIW, I found canola oil (from the grocer, it sustains a fairly high temperature) gives an almost "nitre" blue on common steel heated just past the oxide colors into grey. Surprisingly durable.