Hi Steve:
Thanks. This is another good data point.
-- Tom Fine
----- Original Message -----
From: "Steve Lorenz" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, July 02, 2014 11:02 AM
Subject: Re: [ARSCLIST] small data point -- baking worked for sticky cassettes
> I've done this for Smithsonian Folklife Festival fieldwork cassette
> tapes, very cheap brand from the early 1980s, don't recall at the
> moment, in our small baking oven at 120 degrees for 4hrs. Just enough to
> loosen up unplayable sticky items on a Tascam MK III, but not so worried
> about audio quality of oral histories.
>
> Steve Lorenz,
> CFCH Rinzler Folklife Archive
>
> On 7/1/2014 9:50 PM, Tom Fine wrote:
>> I had two cassette tapes (one owned by me, one owned by a client) that
>> just wouldn't play in any of my tape decks. In both cases, I had tried
>> re-shelling and even replacing the reels because I've heard of cases
>> where the reels warp or otherwise get where they don't fit well in the
>> drive stalks. Obviously, since I could replace the reels, both tapes
>> fast-wound just fine. But with playback, both tapes would play a few
>> minutes and then slow down and then the auto-stop mechanism would kick
>> in because there was too much tension. Tapping the cassettes to loosen
>> the tape-slip mat contact didn't help. Richard Hess suggested, "try
>> baking them," noting that he had fixed unplayable DAT tapes by baking.
>> So I tried 4 hours in the American Harvest dehydrator.
>>
>> The tape I owned (an unknown-brand duplicated tape that says made in
>> Canada on the outer package, with a copyright date of 1984) played
>> just fine, made it through both sides with no problems and excellent
>> audio quality. The client's tape (a 1977 vintage Ampex Plus Series
>> C-90) made it through side 1 just fine and made it through 35 minutes
>> of side 2. Then, it started squealing loudly, and the squealing was
>> audible on playback, so it was a "bow string" kind of squealing across
>> the heads. I stopped playback, rewound to before where the squealing
>> began, ejected the tape, cleaned the heads and the tape path with
>> isopropynol, and vigorously tapped the cassette housing on the table
>> to loosen up the tape pack and the tape-slip pad contact. I then put
>> it back in and it played back the last part of side 2 just fine. An
>> hour or two later, I attempted to rewind to the same place and play it
>> and no matter what I did, the tape squealed worse than before. My
>> theory is that I didn't bake that tape long enough and it very quickly
>> started going back to sticky. Next time, I will try 8-hour baking. For
>> what it's worth, baking did not seem to harm the generic cassette
>> shells I used nor to melt the end-of-side splices to leader tape.
>>
>> I know that the operating theory on traditional sticky-shed requires
>> the tape to be back-coated, so I do not know if this problem is
>> sticky-shed or something else cured by dry heat. Whatever the case, I
>> have a few more circa 1980s generic duplicator-tape cassettes that
>> will not playback right now, and I intend to try baking. I will report
>> back.
>>
>> Also for what it's worth, there was no brown oxide-like residue on the
>> head-cleaning swabs for either baked tape. I still do not know what
>> caused the squealing, and no visible residue came off the heads or
>> tape path (this doesn't mean that some sort of clear goo or a sticky
>> liquid wasn't involved).
>>
>> Has anyone else had success baking cassettes that wouldn't playback
>> otherwise? Do you remember what type(s) of cassettes they were? Their
>> approximate time of manufacture? I'm wondering if we can zero in on
>> certain problem cassette types. I don't think this is nearly as common
>> as in reel tapes, based on my experiences transferring 1000+ cassettes
>> of every era (from the 60s dawn of Compact Cassettes to very recent
>> vintage). These two cassettes, plus a handful more in my personal
>> collection, are the only tapes that ground to a halt in all of my tape
>> decks and couldn't be fixed by re-shelling.
>>
>> -- Tom Fine
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