TubaForum.net

has left me with one word in mind:

"ARGH!"

Slide pliers, lots of old parts saved back, and brass stock and a lathe (to manufacture replacement ferrules) are workarounds for ferrules that have to be sacrificed in order to be removed. Of course - if the manufacturer is still in business, you can sacrifice them and replace them with nice new ones.

When they absolutely can't be removed - at least by me, you might see me cutting the exposed end of a feral at a 45° angle with a saw, grabbing that point of sheet metal with excellent gripping pliers, rolling the pliers at an upward angle down towards the part of the ferrule which isn't yet cut, and peeling It off of the tube. The lead solder will supply very little resistance, so there's no need to heat when using this technique.

When you are saying smaller diameter, I'm thinking trumpet and trombone or maybe baritone horn. To give yourself some leverage, you can solder a trashed trumpet, trombone, or tuba mouthpiece shank into the good end of the tube, and put the mouthpiece rim exterior wall in your vise.

Slide pliers would have been a godsend for this endeavor, I should really invest in some.

What ended up working was using a fairly large-diameter cylinder of metal that fit the diameter of the ferrule pretty well and inserting it up to the lip of the tube resting inside the ferrule, and using that as a lever to wrench the thing off without damaging the tube. The ferrule actually survived, just a bit out of round.

Yeah, almost always even stubborn ferrules can be removed and put back nice. That's always what we hope for.