Corey Bailey
Audio Engineering
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LUBRICATING POLYESTER AUDIO TAPE
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Disclaimer:
Neither I or my company has profited in any way from the people or organizations
mentioned in this article. This would include the links at the end of this article. The
opinions expressed herein are mine alone and do not reflect upon the people or
organizations mentioned in this article.
Some background:
First of all, I want to be very clear: In this article, I am talking about polyester base
audio tape only. This would exclude all acetate base audio tape. Acetate base
audio tape will not benefit from the processes described in this article. In fact, you
can do harm or permanent damage to acetate base audio tape by lubricating it
using the procedures described herein.
For polyester base audio tape there are a number of very good solutions
available. I have tried everything I could find from A to Z and found several that
work very well. However, I have no idea of the chemical interactions with the oxide
layer or the long term effects on storage for all of them except for the one I use.
Some, in fact, leave the tape oily which, for me is not acceptable. Since I want my
customers tapes (including my own) to last as long as possible, I have settled on a
product called Tape Last. I have had extensive communication with the people at
Last Factory, (The company that produces Tape Last) and have been assured that
not only is Tape Last beneficial to the tape itself but it enhances the long term
storage of audio tape. The only history that I have on Tape Last is from my own
tapes that were treated in 2004 and they show no adverse signs from using Tape
Last on them. The tapes have been stored in a closet on an upper shelf at room
temperature. The only downside to Tape Last, that I know of, is that it is
expensive. Particularly in the manner that I use it.
Assessing a polyester base reel of tape for Binder Hydrolysis:
The first thing you will need to do is determine if the tape is suffering from Binder
Hydrolysis (Sticky Shed Syndrome). This subject is also covered in my article:
“BAKING ANALOG AND DIGITAL AUDIO TAPE (OR NOT)”
For 7" reels (and smaller), I insert a pencil into spindle hole and unthread several
layers by hand. This will tell you if the layers have the tendency to stick together. If
you are dealing with a 10-1/2" (NAB Hub) reel, you will most likely have to mount
the reel on the tape deck. Hopefully, the reel brakes on the tape deck will be
disengaged, allowing for easy unspooling of the tape. Carefully unspool several
layers by hand, and observe how the tape comes off the reel. The problem, if it
exists, may not show itself on the first few wraps. The tape should unspool
effortlessly without the layers wanting to stick together. If you are concerned about
the tape being on the floor, use a clean empty bucket or wastebasket to catch the
tape as you unspool it. If you do have to mount the reel on your tape deck, you
can use the other reel to take up the slack. When I check NAB reels on a tape
deck, I will thread the tape directly from one reel to the other, avoiding the rest of
the transport entirely. Use both hands to rotate the reels.
Once you have convinced yourself that layer-to-layer adhesion is not a problem,
backwind the tape to the supply reel and attach about 4 feet of leader to the head
end of the tape. The type of leader (Paper or Plastic) is a matter of individual
preference. Leader has several benefits: It allows for thread-up on a professional
transport and run-up to speed before the beginning of the tape to be transferred
passes across the play head. Consumer decks tend to have shorter tape paths
and many were quite good at recording modulation to the very end of the tape.
Leader keeps the end of the tape protected at the outer edge of the reel and
protects the tape from the unevenness of slotted hubs at the center of the reel.
Eventually, leader will be applied to both ends of the tape. Having leader at both
ends of the tape allows for the transfer of the entire tape, end-to-end.
If, you suspect that layer-to-layer adhesion is present, STOP and consult a
professional. Solving the layer-to-layer adhesion can be tricky and remediation is
best done by someone who knows how to deal with the problem. Often, baking
(done properly) is the answer. If any of the oxide has come off and stuck to the
back of the adjacent layer, it's “game over” for that section of tape.
Once leader is attached to the outer edge of the tape, with the tape threaded up,
play into the tape for about 30 seconds. Stop the tape deck and disable the
transport (As though you are going to edit the tape). Pull the tape away from the
transport and observe all of the stationary parts of the transport (heads, guides,
idler arms, etc.). There should be NO evidence of oxide build-up on any of the
stationary components. Then, with the tape deck is in STOP mode, rotate the
reels back and forth by hand. There should be no resistance. No tendency for the
tape to stick to any of the stationary parts of the tape path. Pull the tape away
from the transport and clean everything. I use denatured alcohol. Inspect the Q-
Tips or cloth that you used for any oxide residue. Presuming that you have a very
clean tape path, play the tape for about 30 seconds again. While the tape plays,
observe how it comes off the supply reel. There should be no tendency for the
tape to stick to an adjacent layer. Listen to the tape while it is playing past the
heads (put your ear up close to the head stack). There should be no squealing or
any suspicious sounds of any kind. Stop after 30 seconds or so, pull the tape
away from the transport and inspect all of the stationary surfaces (heads, guides,
idler arms, etc.) for any sign of oxide deposit. Clean the entire tape path again and
yes, inspect the Q-Tips or cloth that you used for any oxide. With the tape
threaded up, ready to play, rotate the reels back and forth by hand in between
each “play test” to check for any signs of stiction. By now, you have played about
a minute or more of the tape and should not have observed anything out of the
ordinary. It is at this point that I will backwind* the tape to the beginning and
lubricate the entire length of the tape. When I have finished with the lubricating
process, I will attach a leader to the end of the tape and I am ready to begin the
transfer after a rigorous cleaning and inspection of the entire tape path. I will often
transfer side B first to avoid the unnecessary rewinding of the tape even though
the tape only comes in contact with ball bearing surfaces for any operation other
than playing the tape.
*The tape deck that I use for this process (An Otari MTR-15) has been modified so
that the tape itself only comes in contact with rotating bearing surfaces in any
mode other than play. Even the tape lifters have been sleeved so that the sleeves
act as rotating bearings. I will only use the Fast-Forward/Rewind functions to
position the tape prior to transfer. Fast-Forward and Rewind functions are
accomplished using "shuttle" mode with the tape threaded around a reversing
idler, away from any stationary parts of the transport. Know that some tape decks,
such as the Studer 80 series, are designed with only rotating bearing surfaces that
come in contact with the tape for all operating modes.
Lubricating analog audio tape:
Once you have determined that the tape is not suffering from any kind of binder
hydrolysis, you can move on to the lubrication process: Using rubber gloves or
food prep plastic gloves (They’re much cheaper), Fold a 4”X4” piece of Texwipe®
and wet both sides thoroughly with lubricant. I use Texwipes because they don’t
shed (also known as lint free). You can also use Pellon® (available at a yardage
store) or any cloth that won’t shed lint onto the oxide or backing. Place the cloth
so that it covers both sides of the tape. (Fig. 1)
Fig. 1
I use “shuttle mode” on my Otari for this process. On your tape deck, you can
simply bypass the head stack and shuttle the tape directly from one reel to the
other, lubricating the tape in the process. (Fig. 2) You will need to tape the out-
going idler arm so that the tape deck transport is in the “ON” position. (Also Fig.
2). Use the rewind or fast-forward mode to turn the reels. Your fingers, holding the
cloth, will determine the hold-back tension during the shuttle process. This is a
learned operation so I would suggest some practice if you are going to use this
method. Using a non-shed fabric will not harm the tape while you become
practiced at the process. Practicing on a section of blank tape is recommended.
You can also use an 8MM editing machine, if you have one. Using an 8MM editing
machine, you would simply thread the tape directly between reels, avoiding the
editing assembly entirely. Same goes for the practice advice since one hand will
be cranking the reels.
Fig. 2
For all mechanisms:
While shuttling the tape, periodically apply more lubricant to the oxide side using
an eye dropper or a syringe designed to apply liquids (Not a medical syringe with
a sharp needle!). As to how often to apply more lubricant, it’s all a learning
process and it depends on the speed of the tape passing through the cloth or by
the applicator. I would apply a drop of lubricant every couple of seconds with the
tape traveling at shuttle speed (about 3-5 times play speed). Obviously, the faster
the tape speed, the more often lubricant will need to be applied. Since lubricating
the tape using this process takes two hands, one will need to stop and apply more
lubricant when using a hand-crank mechanism such as a film editor. Overlapping
sections of the tape with lubricant is not a problem. Once you have lubricated the
tape end-to-end, Attach a section of leader to the opposite end of the tape. At this
point, you are done and can play the tape. Presuming that you started with side 1,
you can simply flip the tape onto the supply reel and start the transfer. Know that
you will be starting with side 2. This saves rewinding the tape.
Caveat: Although I have used the previously described process many, many
times, the process I now use for lubricating audio tapes involves a (custom built)
stationary felt pad. (Fig. 3) I evolved to the stationary felt pad method because it is
somewhat faster (I transfer a lot of tapes) and it is more of a hands-free operation.
If the tape is in poor shape or the backside needs to be cleaned, I will use the
method described above.
Fig. 3
There is a considerable amount of useful information at the Last Factory website.
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© Corey Bailey Audio Engineering
