Re: [ARSCLIST] powder-like substance from open reel tapes

[Siue Moffat <bk913@xxxxxxxxxxxxxxxxxxx>]

Peter would you recomend these Kimwipes for cds as well??

Thanks
Siue Moffat

----- Original Message -----
From: "Peter@xxxxxxxxxxxxx" <lists@xxxxxxxxxxxxx>
Date: Wednesday, September 29, 2004 12:21 pm
Subject: Re: [ARSCLIST] powder-like substance from open reel tapes

> John:
>
> If you wipe the tapes, two tissues that are non-destructive are pellon
> (available on rolls if you want to set up a semi-automated or
> automatedsystem) or Kimwipes EX-L from Kimberly-Clark (if you do
> the work by hand).
>
> Burnishing is usually done by running the tape past a specially
> constructedpost on a winding mechanism.  Burnishing, when combined
> with a tissue wipe,
> greatly increases the effectiveness of the cleaning process but
> there are
> some specific cautions: Never run a tape over a burnishing post if
> the tape
> exhibits 1) visible edge damage, 2) a brittle acetate base, 3)loops or
> cinches in the tape pack or 4)has splices of unconfirmed integrity.
> Burnishing tapes with these sorts of problems can cause serious
> damage.
> Burnishing got a very bad reputation back in the 70's when a
> company was
> selling cleaning machines that used razor blades.  Further research
> by NASA,
> 3M and Grumman came up with much safer and more effective burnishing
> mechanisms that first used tungsten-carbide and ,later, sapphire.
> The posts
> have to be ground and polished to fairly precise specifications,
> need to be
> positioned to intersect the tape within a limited range of angles
> and must
> be maintained without any scratches or chipping to be safe.  If you
> are not
> very familiar with burnishing tapes, it is usually best to limit
> yourself to
> the less-effective tissue wipe only.
>
> Peter Brothers
> President
> SPECS BROS., LLC
> (201) 440-6589
> www.specsbros.com
>
> Restoration and Disaster Recovery Service Since 1983
>
> > -----Original Message-----
> > From: Association for Recorded Sound Discussion List
> > [mailto:ARSCLIST@xxxxxxx]On Behalf Of John Loy
> > Sent: Wednesday, September 29, 2004 9:56 AM
> > To: ARSCLIST@xxxxxxxxxxxx
> > Subject: Re: [ARSCLIST] powder-like substance from open reel tapes
> >
> >
> > Thank you all,
> > For you timely and in-depth responses. Peter your suggestion I
> believe> is the closest to what I have encountered. The tapes I
> have show no
> > physical or audible signs of sticky-shed syndrome. The tapes have
> also> been cleaned of mold and stored properly in a humid and
> temperature> controlled environment for some time. Most of these
> tapes are form the
> > early 70's and in my experience that is just a little before sticky
> > shed problems started occuring.The main indication that it may be a
> > polyester chemical reminant is that the powder doesn't get on the
> tape> heads so much as the areas of the tape path that the back of
> the tape
> > comes in contact with. I will start wiping or burnishing the
> offending> tapes before playback to see if it helps and of course I
> will keep you
> > all updated. Once again thanks for your help and any other
> suggestions> are welcome.
> > John A. Loy
> > Audio Preservation Engineer
> > Southern Folklife Collection
> > University of North Carolina at Chapel Hill
> >
> >
> >
> >
> >
> >
> >
> > Quoting "Peter@xxxxxxxxxxxxx" <lists@xxxxxxxxxxxxx>:
> >
> > > John:
> > >
> > > "Powder" on the surface of magnetic tapes has been identified in
> > > laboratory
> > > testing as: polyester from the base film (alternately
> identified as
> > > tri-mers), sodium or calcium residue from the magnetic pigment,
> > > surfactant
> > > residue from the manufacturing process, various fatty acids
> from the
> > > lubricant and flowering heads from mold.
> > >
> > > In most instances you can tell whether it is chemical residue
> or mold
> > > by the
> > > visible pattern on the tape surface PRIOR to running the tape.
> Mold> > has a
> > > tendency to appear as round(ish) patches or thin threads.  The
> > > chemical
> > > residues have a tendency to collect in lines on the edges of
> popped> > strands
> > > following a strand or group of strands around part of the curve of
> > > the tape
> > > pack.
> > >
> > > Mold will contaminate your machinery and can be a serious health
> > > hazard.
> > > Non of the other chemical residues has been identified as being
> toxic> > but I
> > > have known operators to get headaches when they became too
> > > inquisitive and
> > > ended up with a face full of the powder.
> > >
> > > Neither chemical decontamination nor baking work well at
> removing the
> > > powder
> > > residues prior to playback and baking can actually increase the
> > > amount of
> > > powder on the tape surface.   Tissue wiping or burnishing will
> > > usually
> > > remove sufficient powder to allow uncompromised playback but the
> > > powder will
> > > often re-appear after a few days or weeks.
> > >
> > > If your tapes have been very cold, you can sometimes get long
> > > crystals of
> > > lubricant on the tape surface.  These crystals can be re-absorbed
> > > into the
> > > tape by gentle heating but this is a very different phenomena than
> > > the
> > > "powder" residues.
> > >
> > > Peter Brothers
> > > President
> > > SPECS BROS., LLC
> > > (201) 440-6589
> > > www.specsbros.com
> > >
> > > Restoration and Disaster Recovery Service Since 1983
> > >
> > > > -----Original Message-----
> > > > From: Association for Recorded Sound Discussion List
> > > > [mailto:ARSCLIST@xxxxxxx]On Behalf Of John Loy
> > > > Sent: Tuesday, September 28, 2004 3:40 PM
> > > > To: ARSCLIST@xxxxxxxxxxxx
> > > > Subject: [ARSCLIST] powder-like substance from open reel tapes
> > > >
> > > >
> > > > I was wondering if anyone had experienced a powderlike substance
> > > from
> > > > open reel tapes from the early to mid 1970's. The brand of tapes
> > > are
> > > > TDK. The powder has been gumming up the machine's transport
> yet has
> > > not
> > > > impeded play or audio quality. When I go to rewind a tape
> however,> > it
> > > > slows the machine and prevents a full rewind at which time I
> have> > to
> > > > clean the machine. The powder is a yellowish-brown and while
> it is
> > > on
> > > > the guides and heads of the machine looks organized but scrapes
> > > off
> > > > into a power. If you have heard of or experienced this problem
> > > please
> > > > respond and let me know what I can do about it or what effect it
> > > may
> > > > have on my machines or the tapes in a long term storage
> situation.> > > Please ONLY helpful, polite inquiries.
> > > >
> > > >
> > > >
> > > >   thanks,
> > > > John A. Loy
> > > > Audio Preservation Engineer
> > > > Southern Folklife Collection
> > > > UNC Chapel Hill
> > > >
> > >
> >
>