TubeNet

I've acquired one of the Chinese Alex clones. It seems to play fine,
but there's a rattle on some low notes that seems to be due to a
loose bell wire. If this were resoldered, I assume it would ruin the
lacquer on the bell edge. I'm wondering if it could be fixed by
running some superglue into the edge of the fold in several spots.

Do any of our resident tuba gurus have a comment or a better idea?

Brian has got it pretty well right here. If you can't get it fixed by the dealer, which assumes you bought it new and/or it is under warranty, having it soldered is the answer.

A good tech should be able to do the job with minimal cosmetic damage. The better it looks in the end though, the more it will cost. The old lacquer must be removed before solder can go in.

Sorry to say, there is not a cheap, quick fix. GLUE is NOT a good idea! It 'might' work for a little while but, sooner or later the job will need to be done right.

What may sound like a loose bell wire may simply be a loose brace somewhere else on the horn. This was the case on my horn.

Tubaryan12 wrote:What may sound like a loose bell wire may simply be a loose brace somewhere else on the horn. This was the case on my horn.

+1.

I've had many, many horns through the shop and have only seen one that had a loose bell wire. Check the horn over completely for loose parts or excessive clearances.... then do it again. Oil is your friend. Use a heavy oil for linkages. Poorly machined or loose-fitting rotors can be a problem. Back bearing caps that aren't fully seated can cause a problem. I've also seen stop arms that are fit too close to the top rotor bearing vibrate. Make sure the stop arms fit tight onto the rotor shaft. Make sure the lyre screw is tight. Check all of the braces. A brace that has a loose flange is easy to spot. However... where the rod enters the socket on the flange can also be loose.

It's easy to suspect a loose bell wire. But I've found that to be relatively rare. ... however... if it turns out to be the case, send the horn back to the seller. Don't try to fix it with super glue. One poster mentioned that the lacquer needs to be removed to resolder the wire. That's easier said than done since lacquer runs INSIDE the area where the wire resides and is almost impossible to clean out.

Superglue is never a good idea as you run a good risk of acquiring a finger print for life on your bell.
Half way through rehearsal one night my clone developed a rattle on certain notes it confused and confounded me until I found the loose stay.
My local repair man used a high temp air gun to resolder the stay loss of lacquer was minimal.