I see that the posts answering your query really don't cover the "baking"
procedure from start to finish, so I'll take a stab at doing so.
You'll need a suitable heat source. Some people prefer inexpensive
convection ovens, which have thermostats that can be set to a suitable
temperature--according to some, 120 degrees, to others, 130 degrees. One
engineer of my acquaintance simply puts the tapes into an UNheated electric
oven with the pilot light on, and the door open a crack. He finds that the
pilot light gives out sufficient heat to make the tapes playable.
As mentioned in one of the posts in this thread, use metal reels. If you're
baking several tapes at one time, put spacers between the reels. Baking
duration: some say two hours is sufficient, others say eight hours. If you
have a tape deck that allows tape to run clear of all "scraping" things
(head block etc etc) it would be worthwhile to do a slow wind before baking,
to relieve any stresses in the tape pack. When you're doing this any
dried-out splices will be immediately apparent, so have fresh splicing tape
and your splicing block at the ready.
Alternatives: Roger Nichols, who used to write a column for EQ Magazine,
once described a vacuum chamber he made to dry out tapes. He preferred it to
the baking method.
As I mentioned in an earlier post, bake only polyester tapes, not acetates.
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