Stewart:
Is the tape sticking throughout or just in spots? If it is sticking throughout, it could be hydrolyzed and we have had some success with incubating (baking) DA88 tapes. If you do try to bake these tapes, however, you should use great care and make sure your baking unit is stable and does not go above 50C. DA88 has a base of PEN, rather than PET, and, I seem to remember that, PEN is more heat-sensitive than PET.
If it is just in spots, there may be a different issue. DA88 uses active metal recording pigments protected from atmospheric moisture by a thin layer of "ceramic armor". If water/moisture has penetrated the ceramic armor in spots (sometimes caused by condensation), the active metal, at those spots, can oxidize. The oxidation process causes severe decay of the tape structure, at those spots (we call this "spot hydrolysis") and the tape will stick. This, generally, happens on the edge of the tape. The inter-tape-wrap adhesion can cause the tape to rip/shear, at these spots, when the tape is unwound. Baking does not correct this issue. On method that does work is: tape the tape out of the cassette, hand wind the tape gently and slowly until an affected spot is detected, treat the spot with a small amount of isopropyl alcohol, wait a few minutes, separate the adhesion with a probe (a dental pick can work), make sure the alcohol has dried, gently wind to the next spot, repeat. This is very time consuming and requires a very delicate touch. It, also, may leave some small edge damage, at the spot, if the oxidation process has "eaten" right through the tape. We have found, however, that the edge damage left is usually small enough to allow the tape to play.
One final note, if the active metal particles, at a spot, have oxidized, the oxidation process can cascade and oxidize nearby metal particles. In addition, at any place on the tape where the active metal particles have oxidized, the magnetic signal is lost. Active metal particles were used in tape to increase data density, as a smaller active metal particle can hold a magnetic moment than can an oxidized metal particle (such as were used in the older tapes). If the smaller, active metal particles oxidize, the small (now oxidized particle) is now too small to hold a magnetic moment.
Hope this helps
Peter Brothers
SPECS BROS., LLC
973-777-5055
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Audio and video restoration and re-mastering since 1983
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Sent: Tuesday, May 25, 2021 2:40 PM
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Subject: [ARSCLIST] DA88 eight-track tapes with binder issues.
Hello,
I have multiple DA88 eight-track tapes with binder issues causing the tape to stick to itself. There is no white powder residue visible. Can these tapes be baked or is there a way to clean them without damaging the tape?
Thank you
Stewart Adam,
Stewart Adam
Creative Audio Works LLC
15 Bay Colony Drive
Plymouth, MA 02360
508-747-1858
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www.creativeaudioworks.com
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