We have had success using cold desiccation.  The process has a number of
positive effects that help to separate the wraps.  First, the desiccation
drives the mold into dormancy which makes the mold easier to remove.
Second, the desiccation reduces some of the "sticky" effect from hydrolysis.
Third, the primary dimensional contraction vector for both reduced moisture
content and reduced temperature in magnetic tape is thickness.  By reducing
the moisture content and the temperature at the same time: the tape becomes
thinner, the pack becomes loser and the wraps "gently" separate.

Warning: if the tape is VERY badly hydrolyzed (to the point where "puddles"
of oligomer residue are visible on the surface), the process can cause
cross-bonding of the oligomer residue into hardened lumps of polymer on the
tape surface.  Since these "lumps" are essentially the same substance as the
binder, once formed they are almost impossible to remove.  This effect is
usually seen only on 2" tape.

To be really effective, the process can take between 30 and 90 days.  Also,
use cold temperatures; do NOT freeze! 

Peter Brothers
[log in to unmask]

Tape restoration and disaster recovery since 1983

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Steve Puntolillo
Sent: Wednesday, January 23, 2008 4:57 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Mould/Mold

Hi Marie --

Thanks for bringing this up. I would also be very interested in this info.

Just wondering if anyone else has had to deal with backcoated tape infested
with mold severe enough to cause the backcoating and oxide layer to merge
(seemingly) inseparably. I have been searching for info on what to do in
this situation but have found nothing. Anyone have any ideas?


-- Steve

Steve Puntolillo
Sonicraft A2DX Lab - Ultimate A_nalog 2 D_igital X_fers

> -----Original Message-----
> From: Association for Recorded Sound Discussion List 
> [mailto:[log in to unmask]] On Behalf Of Marie OConnell
> Sent: Tuesday, January 22, 2008 7:26 PM
> To: [log in to unmask]
> Subject: [ARSCLIST] Mould/Mold
> Kia Ora
> I would like to know if any archive, university or facility 
> dealing with analogue tape and laquer discs, including vinyl, 
> have ever done a study related to the different types of 
> mould/mold that can affect this media.  For instance, is 
> there a particular type of mould/mold that is more likely to 
> affect AMPEX 456 as opposed to AGFA PEM 469 or EMITAPE 4?  
> Or, is it safe to assume that the mould/mold is the same even 
> if it's current state may be dormant?
> I already have a paper written by Jim Thurn from the 
> Kilgarlin Center at the University of Texas in Austin called 
> "Research on Methods to Remove Mold from Cellulose Acetate 
> Audiotape" which I have found extremely useful.  Also, would 
> anyone have Jim's email addy?
> Thanks in advance.
> Cheers
> Marie O'Connell
> Analogue Tape Preservation Archivist
> Sound Archives/Nga Taonga Korero
> PO Box 1531
> Radio New Zealand House
> Level 1, 51 Chester Street West
> Christchurch
> Phone  +64 3 374 8443
> Fax  + 64 3 374 8448