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" <pattac@xxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxx>
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
>