An "easy" blueing process?

[Mark Story]

Try this David:

Heat the screws with a MAPP gas, oxy/propane or oxy/acetylene torch
(propane isn't hot enough) to "cherry red", then quench them in linseed
oil.  I've used this technique for several years, and have been extremely
satisfied with the color, both shade and evenness.  The secret to
consistancy in color is consistancy in the heating process.

Mark Story, RPT

mstory@ewu.edu
Eastern Washington University Music Department
Cheney, Washington, USA

On Tue, 21 Nov 1995, David Parkhurst wrote:

> I'm faced with the need to re-blue a couple of dozen round-head screws
> from the pressure bar of a 1876 Steinway upright. Locally I've not been
> able to find anyone who does this work (except a shadowy individual who
> works through a gun shop every few months or so!) and so wonder if I can
> just do it myself. Does anyone have experience in this?
>
> The only *reasonable* recipe I've found so far involves melting a quantity
> of potassium nitrate (saltpeter), which happens at about 600 degrees F.,
> and dipping the polished and cleaned screws into it for a few moments
> until the desired shade of blueing is achieved then washing them in cold
> water.
>
> I can imagine there could be severe hazards associated with this process
> (like explosions) and so have not yet attempted it.  The screws in
> question are unique in that they possess extra high rounded tops of a
> sort I've never seen available today, so I'd like to reuse them. The deep
> blue of the screw heads contrasts nicely with the brass of the pressure bar.
>
>
> ***************
> David Parkhurst
> Associate member
> San Francisco Chapter -- PTG
> wind@crl.com
>