Corey Bailey
           Audio Engineering
USEFUL INFORMATION
              LUBRICATING POLYESTER AUDIO TAPE
Home Home About Me About Me Services Services Pricing Pricing Glossaries Glossaries Links Links Contact Me Contact Me
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. Acetate base magnetic film is another animal entirely. The acetate base material used in magnetic film is much thicker (about 5 mils compared to audio tape which ranges from .5 to 1.5 mils thick) and so is the oxide layer. I began researching lubricants when I was the Director of Sound at MGM Studios. This was 1993 and our Sound Transfer room was coming across some Reel-To-Reel audio tapes and magnetic film that needed help to play properly. Some wouldn’t play at all. Most of the acetate base magnetic film suffered from a condition known as “Vinegar Syndrome”, but a small percentage had other problems that affected it’s playability. The magnetic film that fell into this category usually appeared to have a translucent white “milky” substance on the oxide. The audio tape, on the other hand, was suffering from the oxide being soft and sometimes sticky. I talked to everyone that I could think of and all of those that were suggested. From Dr. Andrew Lazare of the National Media Labs, I learned the term “Binder Hydrolysis” and of the relatively short life span of magnetic media in general. I also learned of the patent filing by AMPEX Corp. regarding the baking of polyester audio tapes. The patent filing by AMPEX however, didn’t address the issues with magnetic film that we had observed. John Bonner, the Chief Engineer of Warner Bros. Studios in West Hollywood CA, was experimenting the use of baby powder. Although talcum powder did help, it was messy and would clog the play head every few hundred feet or so which would require numerous stops and starts to get through a reel of magnetic film. I decided to experiment with lubricating the oxide of the media that was suffering from playability issues. I used to say that I had tried everything from Alcohol to Xycote (pronounced “Zee-cote”).  I did find a few chemicals that worked.  Alcohol being one of them and Marie O’Connell seems to have perfected the system using alcohol for audio tape playback. Some others that appeared to have positive effects were Decamethylcyclopentasiloxane (D5), Filmguard, Jojoba oil, several silicone based lubricants, Last tape preservative and Xycote (no longer made). My favorites were alcohol, D5, Filmguard and Last tape preservative. Regarding the chemicals tried, I have no idea of their reactions with the chemistry of magnetic media or the long term affects. That said, I do use  alcohol (99%) to treat mold on audio tapes and I have observed no ill effects from doing so. Filmguard was developed for motion picture film and works well on magnetic media. However, Filmguard does leave an oily residue. Last tape preservative is the only one that is made specifically for audio tape, evaporates quickly (like alcohol and D5) and the only one to address storage of the media after its use. The only history that I have on Last tape preservative is from my own tapes that were treated in 2004 and they show no adverse signs from having been treated. The tapes have been stored in a closet on an upper shelf at room temperature. Recently, I revisited those tapes and made higher resolution transfers. I was pleasantly surprised to find that the tapes that should be suffering from Sticky Shed Syndrome had fared very well. I simply re-treated them and they played without having to be baked. The only downside to Last tape preservative 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 AUDIO TAPE” The first thing I do with 7" reels (and smaller) is to insert a pencil into spindle hole and un-spool 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 un-spooling of the tape. I have a couple of TEAC (Brand) NAB hub adapters (TEAC Part # TZ-612) that have a metal flange at the base which allows them to mount to an NAB hub off the tape deck. Then, I can use a pencil threaded through the spindle hole to un-spool a few layers of tape the same as smaller reels. Carefully un-spool 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 un-spool 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 un-spool 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  audio tape reels on a tape deck, I will thread the tape directly from one reel to the other, avoiding the rest of the transport entirely and use both hands to rotate the reels which gives a better feel for the unspooling process. Once you have convinced yourself that layer-to-layer adhesion is not a problem for the first few wraps, backwind the tape onto the reel, mount the reel on your tape deck, 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 however, non acidic paper leader is the only one considered to be archival quality. Leader has several benefits: It allows for thread-up and run-up to speed on a transport before the beginning of the tape to be transferred passes across the play head. Consumer decks tend to have shorter tape paths and some were quite good at recording modulation to the very end of the tape. Leader also 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. Know that sometimes layer-to-layer adhesion won’t rear it’s ugly head until you are at the last few wraps near the end of the supply reel. This problem most often occurs on reels with smaller center hubs (5” Reels, 7” Reels, etc.) which is why you need to pay attention to how the tape comes off of the supply reel until the very 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 audio 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 and the tape threaded up, rotate the reels back and forth by hand. There should be no resistance except for the reel brakes. 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. Use the purest alcohol you can find. Medical grade alcohol is best, if you can get it. Isopropyl alcohol can be found that is 99% pure (or greater). Rubbing alcohol that you get at the drug store usually contains a certain percentage of water and any water is generally not good for the tape path. 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 back- wind* 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, on my particular tape deck, 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 highly 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 and/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. Return to TOP of page © Corey Bailey Audio Engineering