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How to fix flaking oxide on magnetic tape?

Hello, I checked out your web site and found it very informative. But, I do have one question about your LAST Tape Preservative.

I have some old Scotch Audio Tape that I want to transcribe to digital. The oxide is literally flaking off as it passes the pinch roller. I see no flaking near the tape heads or pressure pads. It is visible just where it squeezes through the pinch roller, making a pile as it passed onto the take-up reel.

I never encountered this before. Can you product help with this. Is there anything to be done? -S.C.

Dear S.C.,

The ruboff, or flaking and associated loss of oxide is caused by the imminent failure of the oxide matrix and its ability to hold onto the tape.  The failure is due to the polyester component of the matrix/binder having absorbed moisture from the environment.   And in so doing, it is breaking down into its chemical constituents of acetic acid and an alcohol.  If you have ever opened a canister of old tape and noticed a vinegary odor, that is an absolute indication of binder breakdown.  Some have suggested baking in an oven to remove the moisture.  We feel that the baking process is mechanically very damaging to tape and should be avoided.

The best approach (and one that we recommend) is to place the tape(s) into a vacuum chamber, draw a hard vacuum, and repeat till most of the moisture has been removed from the matrix/binder.  The tape can then be treated with LAST Tape Preservative and used safely for years to come.  If the goal is a safe and trouble free transfer to digital media, the tape that has had the moisture removed can be played and transcribed  without delay, onto new media.  It can be very useful to treat the machine’s heads, guides, and pressure pads with LAST Tape Head Treatment to help ensure a smooth, trouble free transfer.

If a vacuum chamber is not available, tapes may be placed into sealable containers that have a thick layer of Silica Gel moisture Absorbent at the bottom of the container.  This process will remove the absorbed moisture, but the time line is much longer (months rather than days).

An additional check should be made of the machine’s force on the pinch roller.  It may be high enough that it creates a very tight radius bend as the tape passes the capstan, placing additional stress on the matrix/binder components.

I hope this information is helpful!

Best regards, Walter Davies