Trombone Repair

Most of the problems trombones have fit into a few small categories:

• Stuck mouthpieces
• Sluggish or stuck playing slide
• Stuck tuning slide
• Broken solder joints
• Dents

Mouthpieces are easy to get stuck because the mouthpiece shank is conical--it goes from narrow to wider.  When the mouthpiece is placed in the trombone it should slide in until if fits  snugly so it won't leak air and won't fall out.  But if it gets bumped in further, it can get wedged and won't come out.  And with the mouthpiece stuck in the receiver the trombone won't fit in its case.  Pliers and vice grips won't work at all to remove it because trombones are made of soft brass and bend easily.  The technician (and sometimes the band director) has a special tool for pulling stuck mouthpieces; using the right tool the mouthpiece comes right out—without damage to trombone or trombonist.

A playing slide that sticks can be a real drag (pardon the pun).  First a little understanding how the slide works is in order.  The slide is made of four tubes—two inner slides and two outer slides.  The inner slides fit within the outer slides with very close tolerances—the gap is so small that  almost no air leaks through it, so the trombonist doesn't have to blow any harder than necessary. As you can imagine the slides have to be perfectly fitted; there's no room for the smallest of  dents or even a little dirt.  When the slide sticks, you can be sure there's either something inside it or something has been bent or dented.  You can usually tell which it is by how consistent the problem is—if the slide sticks every time and in the same place, something is bent; if the slide sticks intermittently, there's dirt or some impurity inside.

If the problem is dirt, the trombonist can usually remedy the problem himself.  In a large sink or bathtub of warm water and mild dish soap, disassemble the trombone and gently scrub the insides with a  slide brush.  Rinse the parts thoroughly, dry them off, apply a little slide grease to the tuning slide and a little slide oil to the playing slide, and reassemble. 

If thorough cleaning doesn't fix the sticking playing slide, it's either bent or dented and a technician will need to straighten it.  Getting a slide perfectly straight and aligned without giving up any of the close tolerance is an art for an expert, but a good trombone technician gets plenty of practice. 

The tuning slide is the short slide at the back of the trombone used for tuning before you begin playing.  When it gets stuck, it's usually caused by chemical bonding of impurities left on it.  (To prevent that, wipe your slide off periodically and grease it.)  Sometimes a little pressure will break it free—but not with a hammer or pliers unless you don't want the trombone anymore.  The technician will likely try a soft belt and gentle tugs first.  If that doesn't work, he'll probably apply heat.  And if that doesn't do it, he'll have to disassemble the trombone at its solder joints, attach something sturdy to the slide tubes, and apply enough heat and pressure to separate them; then he'll clean all the parts and solder the trombone back together.  It sounds complicated (and it is) but a good tech can get it back together good as new.

Broken braces and solder joints sometimes happen when a trombone is dropped or twisted.  The technician straightens up whatever is bent, thoroughly cleans  both sides of the joint, and fits the parts back into place.  Then with a gas torch he heats the joint to a temperature high enough to melt the solder but not high enough to burn the finish, carefully flowing the solder across the whole joint.  When the solder cools he cleans around it; if he's really good, you won't know he was there.

Dents are where a great technician shows his true artistry.  Using special mandrels and other burnishing tools the technician rubs and gently taps out the dent until the metal is smooth again.  Sometimes when the trombone's lacquer or plated finish wasn't damaged in the accident, you'll hardly notice where the dent was.

Almost all trombone damage can be repaired, and when it's done well, the trombone should play like it did when it was new.