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Re: [ARSCLIST] Tapes and Mold
As most of the replies state, it is very important to wear gloves and a mask
when handling tapes with mold. If you are very sensitive, you may also want
to wear goggles.
Prior to trying to remove the mold, it is important to desiccate the tapes
and drive the mold into dormancy ("sleeping"). Attempts to clean active
colonies off tape are not very successful. By isolating the tape at a low
humidity for a period of time, the mold is driven into dormancy and the
flowering heads become dry and brittle- allowing them to be removed from the
tape surface without "smearing" the mold and causing more contamination.
If the mold is severe enough, it will have penetrated into the wraps. This
requires that the flowering heads be removed from the entire front and back
of the tape to make it safe to play. This only removes the flowering heads
and does not kill the mold. If the tape is again exposed to humid
conditions, the mold will become active again and start to spread. Common
"wisdom" is that the tapes need to be kept below 50% RH for the fungus to
remain dormant. Some fungus, however, can become active as low as 40% RH.
The flowering heads contain the majority of the spores and, if not removed,
running the tapes over the heads during playback will cause spores to be
thrown amazing distances through the room. Inhaling dormant spores can make
you just as sick as inhaling active fragments of the flowering heads.
The only chemical shown to kill just about all fungus and not damage
polyester-base magnetic tape is 111-Trichloroethane. Tapes can be treated
with this chemical to kill the fungus but it should not be done unless you
really know what you are doing! Trichlor is a controlled chemical (ozone
depleter), will damage acetate-base tapes and will melt many plastic reels
and cassettes (but not the poly-base tape).
Because of the difficulties and potential dangers of chemically treating
tapes, common practice is to just remove the surface fungus and keep the
tapes isolated in a dry environment. If you don't have a vault below 40%
RH, you can seal the tapes in plastic bags with chemical desiccants. This
keeps the micro-environment around the tape dry and isolates the tapes to
retard any dispersal of spores.
SPECS BROS., LLC
Tape restoration and disaster recovery since 1983
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx] On Behalf Of Steve Puntolillo
Sent: Friday, March 02, 2007 1:37 AM
Subject: [ARSCLIST] Tapes and Mold
We sometimes get tapes that show signs of having been exposed to
moisture or excessive humidity and therefore mold. Fortunately, I have
yet to see a tape or tape box with what appears to be life growing on
it, but then I'm hardly a mycologist (a person that studies molds).
There's quite a bit of discussion about mold spores being able to
hibernate dried out until given a more favorable set of conditions. So,
what looks "dead" could perhaps just be "sleeping".
What are the reasonable precautions to take when handling these tapes?
Beyond the general conversation about allergic reaction, is there any
serious danger and if so, under what conditions? I want to adequately
protect myself, and even more important, completely protect people
working for me.
Sonicraft A2DX Lab - Ultimate A_nalog 2 D_igital X_fers