Re: [ARSCLIST] Moldy Tapes

[Martin Fisher <wmfisher@xxxxxxxx>]

Will do Peter.  Thanks!!

Martin
  ----- Original Message ----- 
  From: peter@xxxxxxxxxxxxx 
  To: ARSCLIST@xxxxxxxxxxxx 
  Sent: Wednesday, July 11, 2007 1:11 PM
  Subject: Re: [ARSCLIST] Moldy Tapes


  Martin:

  I hope your tap water comes untreated.  If it contains chlorine, and you are
  keeping the originals, there could be some long-term damage.  Chlorinated
  water EATS tape. Even if the project is low budget, I strongly suggest you
  get some distilled water for the "wet" portion of your cleaning process.


  Peter Brothers
  SPECS BROS., LLC
  973-777-5055
  peter@xxxxxxxxxxxxx

  Tape restoration and disaster recovery since 1983


  -----Original Message-----
  From: Association for Recorded Sound Discussion List
  [mailto:ARSCLIST@xxxxxxx] On Behalf Of Martin Fisher
  Sent: Wednesday, July 11, 2007 10:31 AM
  To: ARSCLIST@xxxxxxxxxxxx
  Subject: Re: [ARSCLIST] Moldy Tapes

  Hi Guys,

  Thanks for all the input on the moldy tape query.  

  The tapes in question are 7 inch X 1/4 inch reels of field interviews done
  in the eighties.  The boxes don't necessarily match the tape stock since
  most of the tapes are tails out and I think the reels and boxes were
  shuffled by using the former supply reel as takeup for the next go-round.
  Stock seems to consist mainly of Scotch 206, Maxell XL1 35-90B and a generic
  nonbackcoated 1.5 mil tape on smoky, very nonprecision and nondescript reels
  in white boxes.  (I've run into this same white box type stuff before at the
  Tennessee State Library and Archives.)  No acetate stock encountered so far.

  I've cleaned and transferred about ten out of fifty by doing an initial out
  of the box cleaning of the reel and pack and outer turn layers, then a fast
  forward "dry wipe" followed by a spot wet cleaning (and drying) using tap
  water on heavily contaminated areas.  (Not the most scientific method but
  this is a low budget job and seems to work fine for transfer as all of the
  tapes play fine with no perceptible problems.)

  Best!!

  Martin
    ----- Original Message ----- 
    From: peter@xxxxxxxxxxxxx 
    To: ARSCLIST@xxxxxxxxxxxx 
    Sent: Tuesday, July 10, 2007 1:35 PM
    Subject: Re: [ARSCLIST] Moldy Tapes


    Steve:

    As Eric mentions, long-term-low-humidity exposure will reduce "sticky
  shed".
    It just takes a lot longer than "baking" and has some other side effects
  on
    really bad tapes: if the tape is badly enough hydrolyzed that it has
    "blooming" [actual "puddles" of oligomer residue] on the surface, it can
    cause cross-linking of the oligomers without re-absorption into the binder
    matrix.  This can result in areas of hardened polymer on the surface of
  the
    tape and, in the most severe cases, can "weld" wraps together.  Note:
    "blooming" is most common on 2" tape.

    One of the benefits of low-humidity treatment (especially when combined
  with
    temperature reduction) is that the primary vector of expansion and
    contraction of magnetic tape with either humidity or temperature changes
  is
    THICKNESS.  Unfortunately, if you reduce humidity by "baking", the
  reduction
    in tape thickness from the reduced humidity is off-set by the increase in
    tape thickness caused by the raised temperature.

    Because of this, low humidity treatment will shrink the thickness of the
    tape and loosen the pack while it is also reducing the effects of "sticky
    shed".  When treating tapes with both fungus and sticky-shed for shorter
    times (8-10 days), the slight reduction of the sticky-shed, along with the
    loosening of the pack, can often result in a tape that can be slowly
  unwound
    for cleaning.  Once the majority of the fungus residue is removed, a tape
    with bad sticky-shed can then be baked if needed for playback.  The order
  of
    treatment (heat, cold, low humidity, vacuum, dry wiping, wet wiping, etc.)
    and the number of treatments depends on the specific condition of each
  tape.

    As Eric also points out, the actual removal of the mold is another matter
    and can present serious health hazards if not done under controlled
    conditions.

    Hey- no one said that restoring tape "the right way" is easy.

    Peter Brothers
    SPECS BROS., LLC
    973-777-5055
    peter@xxxxxxxxxxxxx

    Tape restoration and disaster recovery since 1983

    -----Original Message-----
    From: Association for Recorded Sound Discussion List
    [mailto:ARSCLIST@xxxxxxx] On Behalf Of Steve Puntolillo
    Sent: Tuesday, July 10, 2007 12:31 PM
    To: ARSCLIST@xxxxxxxxxxxx
    Subject: Re: [ARSCLIST] Moldy Tapes

    Hi Peter --

    Peter @ specsbros wrote:

    > To drive the mold into dormancy, it is necessary to remove 
    > moisture from the mold, itself, and the tape.  This can take 
    > up to 8 - 10 days of holding the tape in a controlled 
    > environment of around 30% RH.  It can be done somewhat faster 
    > at lower RH and can take quite a lot more time if the RH is higher.
    > (Note: baking is not recommended as, while it can sometimes 
    > work, it can also cause problems with moldy tape- depending 
    > on the type and amount of mold, baking can harden the 
    > mold-related residues and "bake" wraps together).

    So, it sounds like you are recommending a low-humidity exposure at normal
    temperature for several days followed by cleaning. 

    What if the tape also has a bad case of SSS? It seems as though you would
  be
    stopped. You can't spool it to clean it because it has SSS and you can't
    bake it to spool it because it has mold.

    What do you recommend?

    Thanks,

    -- Steve

    ========================================================
    Steve Puntolillo
    Sonicraft A2DX Lab - Ultimate A_nalog 2 D_igital X_fers
    http://www.sonicraft.com
    ========================================================