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SECRETS OF A GREAT PAD JOB

18 Jul

SECRETS OF A GREAT PAD JOB

As most of you know, I do a fair amount of design consulting for saxophone manufacturers outside of our own brands. Last week, I had a lengthy discussion with a factory owner who viewed some very small cost savings as being more important than the ultimate performance of the horn he was planning to build. At issue was the type and installation system of the pads. Saxophone pads and the process of their installation is an area that is widely ignored by saxophone manufacturers and is generally done incorrectly by most repair technicians. A very small amount of additional expense for better or more appropriate materials for padding will yield very significant performance improvements, but unfortunately, this is an area of construction and/or repair where it is very easy to cut corners and leave the instrument in such a state that it cannot reach its full playing potential. The process that I will outline in this article is equally applicable to both the manufacturing of new saxophones and the repadding of existing horns. The processes described require absolutely no exotic or specialized equipment. All that is required is a commitment to doing the very best possible job.

FIRST, ALIGN THE KEYS AND CUPS This is an absolutely crucial aspect of a pad installation, and is the area that is often neglected by manufacturers and repair technicians. Obviously, the key cups must line up with the tone holes for the pads to have any chance at all of sealing. The better the initial alignment, the better the ultimate seal will be. If you take a saxophone that has been played a bit apart and examine the pads, you will almost certainly find that some of the impression rings left by the contact of the pad and the tone hole are off center. This not only detracts from the precise “feel” of the keywork as the saxophone is played, but it also can result in other significant problems.  Off Center Pad Most saxophone manufacturers today outsource their keywork to companies which specialize in making keys. As a result, it is very common to find that when the keywork is installed, it does not perfectly line up with the tone holes. Assuming that the key posts are aligned properly (a VERY necessary first step!), then the key cups themselves can usually be adjusted by slightly bending the ribs which attach the cups to the tubes. Since the same keywork is often used for many different brands, the length or alignment of the rib may be slightly off with regard to the true center of the tone hole, and this necessary adjustment is quick and easy. It is almost invariably ignored by manufacturers and technicians alike.  Bent Key Arms to Center Cup It is also essential that the key cup be absolutely parallel with the top of the tone hole. It goes without saying, of course, that the top of the tone hole chimney must be absolutely dead flat and level. Seriously, if you don’t know how to level the tops of the chimneys, you need to learn how to say “do you want fries with that?”……

SELECTING THE PADS There is no shortage of readily available pads. There is considerable variation available in type of leather, type of felt, type of backing, and an almost infinite variety of resonators styles. The vast majority of saxophone pads are made from sheepskin installed over pressed felt supported by a cardboard back. This combination has proven to work very well, but there are some options available which, although a bit more expensive, can significantly increase performance. In addition to the commonly used sheepskin, goatskin and kangaroo leather pads are sometimes used. Goatskin is extremely durable, but the leather tends to be a little grainy, causing small leaks unless carefully ironed. Goatskin is also quite hard, and some players object to the increased noise which is generated when the pad is closed. Kangaroo leather is the softest and strongest leather used for saxophone pads. Since kangaroos are marsupials, the cell structure differs from other skins, and this structure (the cells are arranged in a lattice like pattern rather than being random as in sheep and goat skin) makes the leather incredibly strong and soft, and greatly reduce the tendency of the pads to stick. Kangaroo pads do not require a treatment to waterproof them. Unfortunately, kangaroo leather is rather expensive, although the significantly increased life makes it cheaper in the long run. The felt used under the leather is either pressed (the fibers are arranged in a random fashion) or woven like any other cloth. Woven felt, although more expensive, tends to be much more stable, shrinks less, and takes more precise cuts at the edges. There are quite a few other ways to improve pad performance, all directed at either increasing dimensional stability (pad shrinkage over time is a problem) or increasing air tightness. The felt can be made much more stable and shrink resistant by spraying it with epoxy (although too much epoxy makes it excessively hard) or a firmer back can be used to force the pad to hold it shape. Coating the backside of the leather with vinyl gives a flexible, air tight seal. Adding an additional layer of leather or other material such as brass foil or Mylar will also help pneumatically seal the pad. Of course, all of these techniques must be employed as the pad is being manufactured. The question often arises as to why synthetic pads have not seen any significant usage among manufacturers. To my knowledge, only the Selmer USA made Bundy and the German Codera are the only horns ever to offer synthetic pads to buyers, and both were significant failures. The Bundy, which had neoprene pads mounted on springs suffered from the combination of a really stupid design (I’m sorry, there’s just no other way to put it!) and extraordinarily poor build quality. The Codera was just too radical for most buyers.

FITTING THE PADS Getting a perfect fit between the pad and the key cup is absolutely essential. If the pad is too small for the cup, the edges will droop and fail to seal. If the pad is too large, the edges will bulge unevenly, causing leaks. If the pad selected is too thick for the key cup, it will hit on the back of the tone hole before the front seals completely. If the pad selected is too thin, the front will hit first and the back will not close tightly. Contrary to what most manufacturers will tell you, the key cups themselves are almost never stamped exactly to specification. A little variation can make a huge difference, and for this reason I always suggest that saxophone manufacturers provide the pad maker they select with an actual set of key cups so that the pads can be made to fit perfectly. Unfortunately, very few of them take this advice, and if you will examine the pad fit in most new saxophones, you will easily see it is generally less than perfect. If you’re having your present saxophone re-padded, you must insist that the technician “dry fit” the pads to be certain of a perfect fit. Should the technician insist that “I have a chart that gives all of the pad sizes for your horn”, merely smile, close your case, and run for the door as fast as you can. Individual horns vary during a production run, and the pads must fit YOUR horn! Any shop in the business of repadding saxophones should also stock any reasonably needed pads in half millimeter size increments. If you don’t keep all of the sizes on hand, you simply can’t do a proper job of dry fitting.

SELECTING AND INSTALLING THE RESONATORS You could spend the rest of your life getting opinions on resonators, and a lot of that discussion is beyond the scope of this article. Here are a few points on which I think there is probably close to universal agreement: (1) steel resonators usually rust out before the pad leather expires (2) aluminum resonators react with the hydrochloric acid in saliva and corrode (3) the screw or rivet used to install the resonator must be made from the same metal or the metals may react (4) if the resonator is installed with screws it can be reused when the horn is repadded. If it is installed with rivets, the resonator cannot be reused. Sizing the resonators is an area where most manufacturers and repair shops completely fail. Both groups tend to take “the easy way out” and use pads that have the resonators pre-attached. This makes it extremely difficult to size the resonators correctly for each tone hole! For maximum acoustic efficiency and dynamic range, the amount of resonating surface must be maximized and the amount of exposed pad leather (which acts as a sponge and absorbs the energy of the sound wave) minimized. Larger resonators do NOT add brightness: they merely allow the horn to operate a maximum efficiency.  “Too Much Is Always Better Than Not Enough” A few manufacturers, although not many, actually pay attention to these easy to verify principles, but most repair shops do not. If the shop you are considering for your repad used pads with pre-attached resonators, simply smile, close your case, and head for the door as quickly as possible. I’m not aware of any manufacturer that currently offers buys a choice of pad and resonator styles. Many years ago, Narita (owner of the Unison brand) did offer some choices, but found that this required stocking a larger variety of inventory in order to satisfy customer orders. This option simply failed to generate the expected additional sales and was discontinued. I was Chief Designer for the company at the time, and we were very disappointed that customers didn’t take advantage of the choices we offered.

INSTALLING THE PADS If the planets are all in proper alignment, then the pads (with properly sized resonators installed) should slip tightly into the key cups and should seal over the tone holes somewhat tightly with minimal adjustment. Most manufacturers have figured out that a very thin layer of adhesive (preferably genuine shellac) is best, provided that it coats the entire key cup, including the edges. A few makers of very low priced horns continue to use hot glue, which is impossible to distribute thinly and evenly. Many repair shops, unfortunately, use FAR too much adhesive, with the intent of “floating” the pad into it’s perfect position. Of course, if they had everything properly aligned, floating just wouldn’t be necessary, now would it? The amount of shellac should be just enough to completely cover the interior of the key cup with the thinnest possible but very even layer, and no more. The purpose of the adhesive is to hold the pad in place, not to compensate for failure to align the mechanism!  FAR too much shellac! Manufacturers have the great advantage of dealing with the instrument while it is (hopefully) at the original specification. The mechanism is most likely properly aligned and should need minimal adjustment. The adjustments that are necessary are almost always done by slight bending of the keys, either with the fingers of a technician or with very light taps of a small plastic headed hammer. Occasionally, wedges or special levers may be used to manipulate the keys  Key Adjusting Tools When repair shops replace saxophone pads, the final small adjustments are often made by allowing the pad to “float” on a layer of melted shellac until it finds equilibrium. This technique is almost never used by manufacturers. The adjustment made by floating should always be extremely small. If a large adjustment is necessary, the keywork is improperly aligned.

FINISHING THE JOB If the mechanism is correctly aligned, the pads should be pretty much leak free. Most of the top of the line factories adjust the compound mechanisms to seal “metal to metal” and add only a very thin layer of material (usually woven felt) to silence the mechanism. The thickness of the material should roughly equal the depth of the seating ring in the pad. The use of thick layers of material to quiet the keywork is asking for trouble over time, as the material will invariably compress with usage over time, resulting in leaks. Under no circumstances should the silencing material be used to regulate the compound keys. The final touch used by the better manufacturers is to seal all of the pads with wooden wedges and apply steam to “set” the seat in the pad. At this point, the horn should completely seal by gravity alone: if you disconnect the springs and allow the keys to naturally fall to the tops of the tone holes, they should seal. If they don’t., further adjustment is necessary. A good pad job is a thing of great beauty to a saxophonist. There’s really no excuse for anything short of perfection, and the cost differential between an average job and a great job is really quite low.

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