I'm on deadline but had to jump in here. This tape-baking is something
that I do for restoration clients, and although I replied to Vivian
privately, I have to respond to this message before folks do the wrong
thing.
[EMAIL PROTECTED] wrote, on 4/9/2008 5:15 AM:
2) The baking process he refers to is a last resort; let's start with the
first resort.
If you know these are gummy tapes, this is the first resort for some
very good reasons.
3) Let's ssume you still own a reel-to-reel player that works (not a safe
assumption unless it's direct-drive; if there are rubber belts involved, they
have a finite lifetime). If you do have one that works, play one of the tapes and
see for yourself what condition it's in.
Do NOT play the tapes. Whether they are gummy, flaking, non-Mylar, etc.,
amateur handling can damage them. Even in otherwise good situations,
splices can fail and tangle the tapes unexpectedly. There are ways of
handling tests, and just playing a tape isn't the place to start.
4) At level one of detioration, there will be drop-outs, because the glue
that attaches the magnetized iron particles (which is how your signal is encoded)
to the (usually) mylar tape base also has a lifetime. Some of the magnetized
iron can literally fall off over time. If you open the box and there's
rust-colored dust in it--that ain't good.
Mylar and usually paper tape binding is good. Acetate tape loses its
binding, sometimes catastrophically. All tape types (and there are
others) can be damaged by "test" playing, especially for those who used
thinner tapes (especially .5 mil Mylar) back in the day when these were
popular with home recordists or people who wanted to get a lot of
recording time and didn't realize the consequences. Even playing thin
tapes can ruin them linearly with folds and creases. Playing tapes with
poor binding can cause oxide to fall off.
5) At level two of detioration, which is what you are worried about, serious
fluctuations in termperature and humidity (particularly humidity) while in
storage will actually turn some or all of the iron/glue/mylar product into
congealed gunk. If that's your situation, you need to follow Christopher's
instructions. Depending on the degree of gunkiness, baking may or may not save a
portion of your material.
Gumminess is not an issue of storage. It's an issue of long-term
chemistry with certain formulations of tape, including very well stored
Ampex mastering tapes from the 1980s. These will go gummy irrespective
of how they were stored; my own top-of-the-line Ampex masters from this
era are all gummy, while most of the Maxell masters are fine.
6) It's a little late for this, but reel-to-reel archivists have always
recommended end-to-end rewinding of all your tapes once a year. That way, if a
process of adhesion to the next layer has begun at a low level, they will get
"aired out." If your tapes are still in playable condition, please consider doing
this in the future.
Do NOT -- repeat do NOT -- rewind potentially gummy or flaky tapes. With
gummy tapes, even if the layers are not stuck together (which is rare,
except at splices), this will cause the gummy surface to heat, stick,
pull off oxide and create clots of oxide on the tape surface that have
to be removed by hand. The gummy tape will ALWAYS get caught in the
guides and usually snap and make a tangled mess. With flaky tapes, the
oxide will shear off in great sheets before there's time to stop it.
When I prepare old tapes, I test first, then if working with a tail-out
tape that requires winding to the front, I slowly wind on a special jig
with the oxide OUT and not in contact with any hardware. Handle tapes as
little as possible; clean and repair splices first.
I have a huge reel-to-reel collection, and the dire predictions about the
shortness of the half-life of the medium are greatly exaggerated. The first tapes
I made in 1957 are still in perfect condition; and keeping them this way is
not the mission impossible it's sometimes made out to be.
1957 was likely acetate. Depending on how those were stored, they will
either be in perfect condition, warped (they are organic materials),
moldy, flaking, etc. You do NOT want to find out they're about to flake
into a pile of oxide when you're test-playing or -rewinding them.
If the tapes in question are masters or only copies, find someone who
has done restoration and get some advice FIRST. They should give you a
free or nominal cost recommendation on one of your tapes. If they've
done gummy or flaky tapes before, they will know almost immediately.
Should yours be gummy tapes, the baking process is not difficult (and
you can do it yourself with a proper baking setup with inexpensive
equipment -- NOT a kitchen stove), but also requires knowing if the
tapes contain splices or have other problems (including splicing
different lots of tape together).
Everyone who does restoration has personal approaches to this problem,
but please do not test-play, rewind, etc., yourself. (As with anyone who
does repairs, I charge double or more if a customer has attempted to fix
stuff themselves first and made things worse.)
Dennis
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