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I tried mounting a lyre bracket on my son's trombone with epoxy, and I really cleaned the mating surfaces carefully.
It fell off on the field.
I also saw a fiberglass tuba with extensive repairs that had been attempted with epoxy. They seemed to have failed too.

NO NO NO!

You can solder with minimal damage to the lacquer. People who are very careful can do some very clean work.

The key is not to rush. You have to take your time preparing the area, make sure the pieces fit together as close as possible and re-assemble with a low heat flame. You need to gradually bring the metal to temperature to avoid burning lacquer.

There are also products like Kool Jewel (I think that's right) to help act as a heat sink.

Some times it is impossible to protect the lacquer as not all lacquers are the same. Some are more durable than others.

Epoxy should NEVER be used to assemble horns or braces that should be soldered.

I use epoxy for one thing: fiberglass sousa bodies and bells.

The joints between the lower stack, bottom bow, and bell on some saxophones are held together with epoxy. It wouldn't surprise me to see it used on tubas some day... if it hasn't been already. I wouldn't put anything past the industry.

Although it's possible to solder parts together that are lacquered.... it's VERY difficult to get a GOOD solder joint when you're trying to keep the temperature low enough to keep from burning the lacquer. Some of the new lacquers will tolerate maybe 600 degrees but that's still very close to what it takes to get a good solder joint. The integrity of the joint should be given more consideration than the end appearance of the lacquer... I think, anyway. What good is pretty if it runs the risk to coming apart or leaking?

KiltieTuba wrote:Uh, what about on silver plate? Would the high temp effect the finish?

It takes 450 degrees or so to make a good solder joint. The problem comes when soldering on two parts with different masses. For example... attaching a small part to a large part requires that BOTH parts attain the desired soldering heat. This is a BIG problem when attaching those darned nickel-silver bow guards to German tubas. Those bow guards heat up really fast while it takes a bit of time to get the heavier material in the bows up to heat.

You've just gotta learn how to 'play' the heat to get both pieces to soldering temperature at near the same time.

Yes... silver-plated finishes are easy to damage with heat. Also.... silver plating LOVES lead. I still use leaded solders but NEVER use over 30% leaded solders when working with silver finishes.

KiltieTuba wrote:Uh, what about on silver plate? Would the high temp effect the finish?

The major concern is slopping the solder on the finish. You won't actually damage the silver with the heat required for soft soldering.

The key to soldering on silver plating is to, again, have both areas being soldered be perfectly clean, have both pieces fit as close as possible and only use a conservative amount of flux.

Using a low heat will help you control the flux. If the flux boils out or starts to run, clean it up and do not continue until the area has been cleaned of flux.

If you are relatively inexperienced you can use anti-flux (which I don't particularly care for), crayons or contact cement to keep the flux where you want it so you don't have to clean up as much excess solder.

After soldering, you will need to clean up the solder entry point.

Again, very skilled people can do this VERY cleanly.