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Solder Repair Hints
Q.  I bought an old Martin Busine alto sax that has a problem with the neck. It seems that the neck has come apart at the solder joint where it attaches to the section that fits into the sax. I am very good at soldering brass and copper, however, I have never worked on a piece that has an outer polished finish. I use high temp MAPP gas propane torches and I would assume that you folks use other types of specific equipment. Could you advise me as to whether if would be wise to attempt this myself and what kinds of tools I would use. As I said, I am quite comfortable doing the actual solder job, but I want to use the right stuff……. Thanks, Robert …


A. That’s a common neck problem that’s easily fixed. It happens when some idiot unwittingly tries to remove a neck with the neck screw still tight. You can put a lot of torque on that joint twisting from the neck end – and a mouthpiece makes a lovely palm grip to assure the nasty deed is efficiently done. We call such things ‘idiotifications’, which is saxophone modifications performed by idiots in the privacy of their own homes.

The fact that a surface is polished isn’t really relevant to soldering heat. We solder bare brass or nickel, gold & silver plated saxophones all the time. When there is hazing the remedy is a simple matter to applying a little Hagerty All-Metal polish. The rub comes when a surface has been lacquered. You usually see lacquer over newer brass saxophones, but sometimes on other metal finishes, as well. You need to investigate to know what you’re dealing with. If you put soldering heat to a lacquer surface you’re going to burn lacquer no matter how careful you are. In that case you must have a post-solder recovery strategy in mind.

The most common recovery technique is to remove the damaged lacquer back to an even border with the pristine (OK, maybe undamaged is the operative term) remaining finish, polish the bared brass, then spot lacquer with either a clear or gold tinted instrument lacquer. Ferree’s Tolls sells spray cans of both. With some practice you can get pretty good at spot lacquering. In the case of a sax neck you can always strip the whole thing (do it before the heat if you go that route) and refinish the complete neck. Then your concern is matching the neck finish color to the whole sax body. Needless to say that prospect is problematic on aged brass lacquer finishes.

If you’re really good at soldering you may be better than most sax techs. Judging by the work I’ve seen over the years I’d have to say that the average soldering skill level is pretty low. As for gas, I’ve seen everything from propane to acetylene. Here at CS we use butane (pencil torch) for pad glue work, propane (hose rig) for some large pad removal jobs, and MAPP gas (also hose rig) for soldering. Over the years I’ve experimented a lot with gas & heat, and my conclusion about soldering saxophones goes like this: There is a minimum cumulative amount of heating required to do the job. If you know what you’re doing the max heat level is always the minimum required for the task at hand. Propane, MAPP & acetylene all are capable of reaching the required working temps for soldering. The variables are the time it takes to reach the optimum working temp and the potential to exceed the optimum temp. If you have the skills to control the rogue variables then the only difference in the gas you select is the time required to reach working temps. Put another way: There are advantages to working quickly when soldering. The faster you do the job the less chance of exceeding the minimum cumulative heat needed to be effective, and my instincts tell me that the potential for collateral damage (finish burn, setting pads, corks & felts ablaze, adjacent parts floating away, etc.) is less.

The real difference is in how you plan & execute a solder repair. Let’s assume for discussion purposes that you can position & hold the object parts where you want them, so we can focus on how much solder is required & how to assure we us the minimum needed to do the job. As competent solderers we already know that the thinnest solder layers make the strongest bonds, right? I’m going to dip into what may read as sacrilege to some a bit now, but if you have a clean, fresh break in the original factory solder you probably don’t need to do anything except apply a little flux, clamp the parts back in place & induce the working heat. Even if the joint has been lose a while and has become dull or dirty, if you can simply freshen the surface (Dremel wire brush!) you can usually reattach successfully with no additional solder.

Of course if the parts have to be straightened, dents lifted from under posts (ALWAYS — leveling a post atop a bed of molten solder is akin to walking on water!), or globs of non original solder cleaned up from past amateurish attempts, you will need to remove the old solder in order to do the work effectively. In that case there are two techniques for assuring you reapply a minimum amount of solder. The first is silvering, which guys that do electronics soldering know is merely pre coating one or both surfaces to be attached. After silvering your parts the task is the same as with reusing original solder on a clean break: apply flux, clamp & heat.

The second tactic is to pound a small piece of solder on a jeweler’s anvil until it is paper thing, then cut it to where the piece is smaller than your ‘footprint’ where the two parts will meet. The flux paste makes a great temporary adhesive to hold your solder to one of the parts for positioning while you apply the heat. For this method you need to be aware that clamping is less useful than holding the parts together with tongs. That’s cuz when the solder reaches the flash melting point it will leave a minuscule gap that must be immediately pressed closed. IF you don’t push the parts together they won’t rest flush together (you’re walking on water, again). The solder will still solidify & hold (at least for a while), but your parts won’t be in exactly the correct orientation to one another. So pressing with your tongs is a must even if you have the parts clamped. Actually, with the this method you know exactly when to remove your heat cuz you feel that little ‘thump’ when the solder melts & your gap compresses closed. This process feedback assures you don’t overheat your work.

For your neck project I’d try to go the reuse existing solder or silvering route. That joint is much too snug to work in a thin sliver of solder. Of course you can always treat that joint like sweating pipe — but I wouldn’t unless you’re prepared to do a lot of excess solder cleanup or to live with substandard results. :-( 

All that’s left is deciding on your neck finish cleanup strategy – which should always be a part of your overall task planning … :-)

follow-up report from Robert:
Q.  I was able to do the repair by “gleaning” from your instructions and sort of just going for it. It went as follows: 1) cleaning up both surfaces; 2) flux on both pieces; 3) heating up the sleeve piece & quickly assembling the 2 pieces; and finally,  just a bit of solder added and then wiped thoroughly. There was no damage to the neck finish and it works great! Thanks, Robert …

A. You are quite resourceful, Robert. I follow what you did. The result was heating the sleeve to a much greater degree than required, but not applying heat to the neck itself. It worked because those two pieces self align; i.e., one fits entirely within the other to the exact point of alignment. If your solder stayed liquid from the heat applied to just the sleeve throughout the entire cycle you described that sleeve must have been red hot – something I would not recommend. I’m glad your process worked for you on that joint — even though it probably wouldn’t be successful on other saxophone solder repairs. For instance, if you had chosen to heat the neck pipe itself all your octave mounting gear would likely have floated loose & slipped out of place. I assume you realized that in your planning. You chose the right part to heat. I wish you much enjoyment from that instrument. There’s no feeling like playing a saxophone you’ve nursed back to health with your own hands … :-)

Additional Comments
There is often more than one way to perform a saxophone repair. When I make specific recommendations of a technique it is because I have taken into consideration the pitfalls I am familiar with and tried to explain them for you. While Robert’s method worked in an isolated case, it may have had horrendous consequences on other parts of a saxophone. If you attempt solder work on a saxophone please give the ‘no more heat than required to do the job’ dictum the same weight as the law does the ‘no more force than necessary’ restrictions placed on our fine policemen & women as they carry out their duties. Your saxophone bears only the most basic resemblance to your home’s plumbing … :-) 

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