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From: Patent Tactics, George Brock-Nannestad

> I recently did a job where I was able to create tracking through with 
> plastic clay.
> 
> Steve Smolian

----- wow! Was that a lacquer record? The layer is awfully thin. My main use 
of plastic clay has been to exclude oxygen on cracks cemented with cyano-
acrylate (shellac-base record), because it can be removed from the grooves 
afterwards without damaging them.

Kind regards,


George

> 
> ----- Original Message ----- 
> From: "George Brock-Nannestad" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, August 20, 2008 12:16 PM
> Subject: Re: [ARSCLIST] ET help!
> 
> 
> > From: Patent Tactics, George Brock-Nannestad
> >
> > Matt Sohn recalled:
> >
> >
> >> >> I've a pretty good hand at transferring ETs, but the
> >> >> cracks in the lacquer
> >> >> make this one a real challenge.  Is there any way of
> >> >> restoring these
> >> >> grooves?  I thought of prying off some of the lacquer in
> >> >> chunks to glue back
> >> >> in place, but I'm not sure the grooves would line up even
> >> >> then.
> >>
> >>
> >> I recall talking to someone a long time ago who said he used
> >> clear nail polish to fill in the cracks. I don't remember
> >> who it was or how exactly he did it, or what possible damage
> >> to the disc might result from such a procedure, but I
> >> thought I'd pass it along..
> >
> > ----- I would not recommend nail polish. While the softening agent is
> nice
> > and makes for a tough coat, the solvents are the same as for cellulose
> > nitrate - because nail polish is mostly cellulose nitrate! This means
> that
> > you would eat into the edges of the lacquer layer. This makes for better
> > bonding but also rounded curves. And you still have to cut a groove to 
> > carry
> > the stylus from where it leaves lacquer to the correct place at the other
> > end
> > of the gap. And, as I said, nail polish is tough!
> >
> > I have had good results with waxes (low-melting micro-waxes). BUT, waxes
> > usually implies heating and applying it in liquid form. On an aluminum 
> > base
> > the heat of solidification will be distributed to other areas, causing
> > differential heating, and who knows what damage that might cause. On glass
> > it
> > is safer. Using a solvent for the wax that is not also a solvent for the
> > cellulose nitrate (paraffin would work for some waxes) would permit
> > application of the liquid and then wait for the solvent to evaporate.
> You
> > need to cut grooves under the microscope to connect correctly, but that
> is
> > simple - the worst crack I have come across was 3.5 millimeters (narrowing
> > to
> > zero over 40 mm, and a ruler to support the scriber was quite sufficient.
> > And
> > the wax is very easy to cut.
> >
> > But you have to remember that the shrunken lacquer also has a shrunken 
> > time-
> > base, so it is not just a question of removing the clicks of silence, but
> > of
> > stretching time, perhaps 5%, perhaps less, of the sound you do obtain.
> >
> > Again, like Eric said, it takes experience, and whose lacquer record is
> to
> > suffer?
> >
> > Kind regards,
> >
> >
> > George
> >