[CAUT] Teflon AND verdigris?

[Douglas Wood]

I believe the verdigris is actually copper oxide. It is green, and is  
from the center pin, which is partly copper. As to why some oxidize  
more than others, well there "oxidizers" out there. There's always  
oxygen, but some compounds accelerate the reaction. Besides the  
contaminant gumming up, the pin's surface corrodes and is less smooth.

Based on that, I'd think that simply repinning with a new pin should  
take care of the problem. Yes, there may be residual from whatever  
substance (lubricant???) was applied, but the Teflon is pretty much  
completely inert. And very stable, chemically. Short of temperatures  
in excess of 500 degrees F. And it should take quite a while to  
develop new verdigris (copper oxide) from a small amount of residue.  
I suppose that if you want to be thorough, you could ream for the  
next size pin whether the bird's-eye needs it or not. New Teflon  
surface plus new center pin would minimize any tendency to corrode.  
But I wouldn't think it would make much difference unless your  
atmosphere is more corrosive than average. (Think acid rain...)

Doug


On Nov 5, 2008, at 1:29 PM, Mark Cramer wrote:

> Actually the verdigris is on the centre-pins, the wooden flanges  
> and on the brass rail.
>
> I’m just surprised to find verdigris in this vintage of action,  
> believing as well that it was a paraffin thing of the past.
>
> David Kirkland suggested some kind of lube used after the  
> instrument left factory may have caused this. And the presence of  
> center-pins with ends nipped certainly indicates some kind of  
> generic field-work.
>
> Meanwhile, we’re experimenting with Ballistol.
>
> I know from past experience that any number of treatments work on  
> verdigris in the short term, and some like Bourbon, last a long while.
>
> My only concern is not to damage the Teflon in the process. To that  
> end, we’ve got a Teflon bushing soaking in Ballistol overnight…  
> though I’m not sure exactly what I expect to happen…!? :>)
>
> In any case, we just need to get some useable up-weights happening,  
> as this instrument, in it’s otherwise original condition is really  
> quite nice.
>
> So tomorrow, unless warned otherwise, I think we’ll go ahead with  
> Ballistol.
>
> Thanks,
> Mark
>
>
>
> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf  
> Of Avery Todd
> Sent: November 5, 2008 3:01 PM
> To: caut at ptg.org
> Subject: Re: [CAUT] Teflon AND verdigris?
>
> I don't understand how there can be verdigris on teflon. I thought  
> that was always a felt/wood/parrafin thing. Can someone enlighten me?
>
> Avery Todd
> Houston, Tx
> On Wed, Nov 5, 2008 at 1:46 PM, Mark Cramer <cramer at brandonu.ca>  
> wrote:
> Regulating a 63' Teflon action L for a good friend, I was surprised  
> to find verdigris at the hammer flange centers.
>
>
>
> This is a solid Teflon action with nice firm centers and no clicks,  
> however with verdigris, hammer-flange friction in some cases  
> exceeds 10 grams.
>
>
>
> Steinway warns against lubing Teflon parts, nonetheless I have to  
> wonder if there is some Q & D means of easing the verdigris without  
> damaging the teflon?
>
>
>
> I know that whether we properly disassemble, clean, ream and re-pin  
> the parts, or simply squirt in a bit of miracle juice, the  
> verdigris will come back. However, something that will extend the  
> use of these otherwise moderately worn parts, is entirely  
> appropriate for this particular piano.
>
>
>
> Given the recent discussion of lubing key-bushings, I'm just  
> concerned that the solvent/carrier in CLP for instance may dissolve/ 
> harden the Teflon, while perhaps ProLube may not?
>
>
>
> Anyone know for sure?
>
>
>
> Thanks,
>
> Mark Cramer, RPT
>
> Brandon University
>
>

Doug Wood
School of Music
University of Washington

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