capo-hardening?

[Bdshull@aol.com]

Hi, Mark,

I used a local welder who had experience in TIG welding.  The TIG device will 
only heat a small area, although the temperature is still extremely high.  
There is considerable control.  He was able to reflow the outer v-bar surface 
to a fairly smooth contour, requiring almost no grinding or filing to dress 
the surface.   My thinking is that the less material "re-flowed" the better 
to maintain the proper dimension, and the TIG welder only affects a few mils 
of the surface.

Based on Roger's post, I'm guessing the key is the skill of the welder, not 
just the type of welding device used.

You are probably right about your assessment about the V-bar, but if that 
assessment is based on zinging strings it may be just the strings which are 
at fault.  Replacement of strings is the best solution there.  On the other 
hand, some v-bars were pretty soft from the beginning and may have broken 
down some in heavy use.  
My metallurgy knowledge is non-existent, but I wonder about the hardness of 
cast iron at the v-bar from normal surface cooling at the time of 
manufacture, vs. torch-hardening and/or TIG reflowing. 

Bill Shull

In a message dated 9/21/01 4:04:31 PM Pacific Daylight Time, 
baldyam@sk.sympatico.ca writes:

<< Hi Mark,
               I dress and shape the capo bar, then take the plate to a
 black smith, who heats it with a torch and quenches it with oil.  He just
 gets the edge of the capo a dull cherry red, then pours the oil on.
 
 Regards Roger
 
 
 At 03:24 PM 9/21/01 -0500, you wrote:
 >
 >In discussions about string-termination noise, I've heard mention of (re-
 >hardening duplex surfaces, but have no idea how this is done.
 >
 >1.) cold hardening with a burnisher, or gentle peening with a hammer?
 >
 >2.) heating with a torch, arc-welder?
 >
 >3.) a combination of the above?
 >
 >To those who have had success, I welcome your advice.
 >
 >thanks,
 >Mark Cramer,
 >Brandon University >>