[TheForge] Gun blue finishing

[peter fels & phoebe palmer]

On 1/12/2011 11:10 AM, Mike Spencer wrote:
>> Put the piece in a slowly rising toaster oven till it turns
>> blue..slower is better...surface prep is critical.
> I did some inlayed belt buckles like that.  Polish, clean, heat very
> carefully. Result is a beautiful peacock blue.
>
> Two problems arose:
>
> The blue isn't very durable. Without a protective finish (or after the
> finish has worn off) a single droplet of water will remove a spot of
> blue if allowed to remain for a while.
For sure..it's only a few molecules thick and any coating seems to damp 
the color.
> And I didn't think ahead on the brass inlay.  Used a lubricant to cut
> the inlay dovetails.  When the "clean" piece was heated to get the
> blue, wax boiled out from under the inlay.  Boiled that one in lye for
> a while, reblued.  After that, I boiled them in lye *before* hammering
> in the inlay wire.
Groan
> I've read about a bluing process that involves immersing the workpiece
> in molten potassium nitrate and sodium nitrate.  Anybody have
> experience with that?  IIRC, it was being used on spurs for drugstore
> cowboys.
Selenic acid was the old blueing standard.."A class B poison". I used to 
get good results putting it on wet with a slow power wire brush, but i 
always got sprayed in the process and had stained hands for 
days..finally decided it wasn't such a good idea.
>
> - Mike
>