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Why is my tape sticking and smelling like vinegar?


I have a small collection of E.M.I. Classical 2-track prerecorded tapes from the late fifties/early sixties.

One of the tapes is ‘sticky’. It is fine until about 80% of the reel is played then it just stops completely. I think it needs to be cleaned. [Can you give me general advice on cleaning?]

Best regards, K.B.

I can state that the use of alcohol and solvents in general are bad for tape. Tape that is sticking, as well as tape that is suffering from oxide rub-off (or shedding) is experiencing failure of the binder matrix that holds everything together. That matrix is a polyester based plastic. And polyester is made by combining alcohol and acetic acid under elevated temperature and pressure. If you have ever opened a tape canister and smelled a vinegar order, you are smelling evidence of tape in which the binder is beginning to dis-associate. This occurs when tape is kept in an environment where it can adsorb moisture from the atmosphere. Ideally, tape should be kept under conditions of relatively dry storage with Relative Humidity of 40% ( not more than 55-60%).

Regards, Walter

Editor’s Note: LAST Tape Preservative does clean tape and seals out the moisture that destroys the binding matrix. It does not contain alcohol or solvents.