Fire Bluing

[Laredo7mm]

I just tried fire bluing for the first time and was hoping you all could give me some advice. My test piece was a 1.25 diameter piece of round stock about ½ inch thick. I ground and polished one face of it and put it into my heat treat furnace. The furnace was at about 550 deg F to start. I just finished making my own furnace, so I am still getting used to the controls. Anyway, 550 deg was not giving me any color, so I bumped up to 575 deg. The temp seemed to be stable at 575 so I left her to bake for a while. When I returned an hour later, the temp was actually around 600 deg F. I checked the piece in the oven and it looked good. I took the temp back down to 575 and let her cook for another ½ hour. I then took it out and quenched it in oil.

So now I have my fire blued piece that is not quite what I expected. I have only seen pictures of fire blued material, but not any in real life. My piece has a very nice blue around the edge of the piece that is about 1/16 of an inch wide. The center of the piece is kind of a purplish color. Is this normal? How do I get that nice blue color throughout the piece? Did the blue come from the 600 deg F and it did not soak at that temp long enough to penetrate the whole piece?

Any advice you have will be greatly appreciated.

 

[mikeS]

i do it with a torch, or forge, you have more control over the apperance, eye control. heat very slowly and bring up to the clor you want, quench in water to halt the color. if done correctly and with practise you should be able to bring the piece to color desired without quenching in water.