[pianotech] Scrapers - 96 years of Pledge

[Ron Nossaman]

On 7/16/2012 7:47 AM, Al Guecia/Allied PianoCraft wrote:
> Ron, is this the process you used?

I used an oxy-acetylene torch, small torch tip, and an acetylene rich 
(carburizing) flame mix. Cut back on the oxygen to extend the blue cone 
in the flame a bit.

http://www.embraco.com/DesktopModules/DownloadsAdmin/Arquivos/Hjmk2nyG9t.pdf

This will add carbon to the steel as it heats up. Heat the edge to the 
point the steel starts throwing off small sparks and you can see scale 
deposits on the steel, and water quench immediately. Don't temper it 
afterward, because the interior of the blade is still low carbon, and it 
won't get brittle enough to be a problem. The edge, however, gets 
considerably harder.

Ron N