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Hot bluing damascus

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Question for the pros. When you are hot bluing your damascus blades, do you leave your blades in a highly polished state for the bluing process or do you etch with acid first and leave it as a dull finish for the bluing process? My billet consists on mild steel and 15N20.

If it is highly polished for the bluing, will the 15N20 remain mirror-like and the mild will take on the color of the bluing yet remain polished looking?

Thank-you.

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since bluing is a surface treatment, i would have thought etching would negate the bluing process....

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Look at blued surfaces on guns,, some are done with a wire wheel some by media blasting then blued,,some are mirror finished then blued...The 15n20 will remain lighter,and both will shows scratches if you leave them in them.

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If you want real contrast, pure nickel (201 sheet) wont be effected by the salts, leaving that layer silver, as for a mirror, if you start the bluing process as a mirror it will remain so unless excessive length of time in the salts of course.

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Thanks guys.

Last night I polished this pendant (see thread link below) to a mirror polish then etched it with Ferric Chloride. Before that I etched it with vinegar overnight. Right now I'm just experimenting to see how different etchants work on this piece and this combination of metals. This whole thing has been a learning process for me.

http://www.iforgeiron.com/topic/26579-my-first-shot-at-pattern-welding/

Thanks for the info on the 201 Steve. I was under the impression that higher nickel steels like 15N20 would also not be affected by the bluing.

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When I hot blue pattern welded blades I do not etch. I am after the high gloss high contrast look. And I only do this when I have put nickel into the mix. I woiuld etch if I wanted the topography of a deep etch.

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Thanks Rich. I think I will be giving that a try. I will re-polish it tonight and get it blued tomorrow. I stopped by the gunsmith this morning and I lucked out. They only do about 2 batches of hot bluing a year and one of them is scheduled for tomorrow.

In your opinion will the 15N20 still contrast strongly with the mild steel after bluing? Steve Sells mentions that the pure nickel (201) gives the highest contrast. Will the 15N20 resist 'most' or 'some' of the bluing action of the salts that will darken the mild steel?

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We used Brownell's salts when I worked at the gunsmithing shop. For a shiny finish we only went to 320 grit, as he felt it gave better results. He had a few guns that he had polished to a higher luster, but the blue didn't last as long. The rougher finishes held the bluing better. I hand sanded most of the ones I prepared, as the buffer would smear the metal closing the pores. I never used Du-Lite chemicals, but I have heard good reviews for them.

As to color, I do know that some alloys will give a purplish hue - Winchester receivers, and heat treated items like some bolts, and Krag Jorgensen case hardened receivers. A lot of receivers are made of a nickel steel, and they come out really black. Guess you will find out for certain tomorrow.

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Ok, it was a day of failures and successes. The failure was the bluing turned everything pretty black. I didn't like it (lacking the contrast I was hoping for) so I decided to buff off the bluing and re-etch. I discovered that a light buffing took the bluing off the 15N20 while the bluing remained on the mild steel, giving me the effect I was looking for.

This is a 200 grit polish followed by an overnight etch in vinegar:
Vinegar.jpg

This is after some more polishing and buffing:
Polished.jpg

This is after a 10 minute etch with Ferric Chloride following the buffing:
Ferricchloride.jpg

Then I polished and buffed it again and had it blued:
Blued.jpg

This is after a final light buffing to remove the bluing on the 15N20:
FinalPolish.jpg

All in all it was a very good learning experience. First time making pattern welded steel, first time etching, first time bluing, and I'm fairly pleased with the final result.

Thanks for the advise everyone.

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That's a heck of a first go Mark! Well done.

Frosty The Lucky.

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Thanks Longhunter. Yes, it is a pendant for a necklace.

I made this one from the same billet for my wife this weekend. It is just a ferric chloride etch with a spray-on polyurethane clearcoat to prevent rusting.
OvalPendant2.jpg
OvalPendant1.jpg

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I think the important thing you learned was that you need to experiment with PW patination to figure out what works best for what *YOU* want!

Thanks for the various pictures showing different processes on the same piece.

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Thanks Julius. If you are asking about the triangular pendant, I think it was about 2.75" high and about 1.25" wide. I gave it away so I can't measure it now...

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That's bigger then I thought it was lol. The next time you make one you should try hardening it. I noticed that the damascus I have etched differently when it was hardened. I know you just used mild steel but the 15n20 should give it enough carbon to make a difference. When I played around with it I got better a defined pattern with the hardened stuff. I don't know of it was from it being harder or just having finer grain.

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I probably won't do it until next spring now. You are less than 3 hours away so it would just be a day trip. We can try to make you some billet for your awesome knives.

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I have 1084 and 15n20 :) that would be awesome Mark. I could leave early in the morning and be able to spend a good day out there. Just let me know what it would be worth to you.

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I highly doubt that I would be able to teach you anything lol. Thank you for the invite I think it would be a blast.

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