Chris, I'm not an expert on magnetic tapes, but I have heard reliable
warnings that the home baking idea may cause genuinely irreversible
damage to your tapes.  There has been much discussion of this subject in
the Conservation Distribution List maintained by Walter Henry at Stanford
University.  I can review that discussion via the CoOL Data Base through
the path:  Gopher/Other Gopher and Info Servers/WAIS-based Info/alphabetical
list/C/CoOL.  You can tell my lack of sophistication about the Internet,
but if you can get to a WAIS-based server you can reach CoOL.  Search
magnetic or sticky on CoOL or CoOL-cfl.  E-Mailed documentation is available
from Walter Henry via <[log in to unmask]>.
 
Your warning that the life-expectancy of tapes (computer and video as
well as audio) is well placed, but the 15-year life expectancy is only
approximate.  Life expectancy can be significantly reduced or extended by
the temperature and relative humidity of storage, and by whether the tape
is actually played.  Low temps and RH, with no play, extend LE.  Many
sound archives recommend reel-to-reel format for long-term preservation,
partly because cassettes are vulnerable to mechanical stresses.  I have
been warned against DAT for preservation because the tape is
exceptionally thin; there may be other vulnerabilities in this medium as
well.  A commercial user recently told me he'd experienced a 20% loss of
data on DAT over 4 years (private communication).
 
The best strategy for preserving your tapes, even at home, is to keep
them in moderate conditions (cool, controlled humidity, away from dust
and pollutants); to sample them periodically for indications of loss and
to copy immediately if deterioration is found; to copy important tapes
even in the absence of obvious damage on a cycle like your recommended
10-15 years; and to handle them carefully.  Baking should be a last and
desperate resource.
 
_________________________________
 
Karen Motylewski                                508-470-1010
Northeast Document Conservation Center          508-475-6021 fax
100 Brickstone Square                           <[log in to unmask]>
Andover, MA 01810                               Use KM in subject field