I realize this has been asked before. My old Burke has a stuck slide, best way to get it loose? I tried contacting Michael but no response. Thanks, John.
Maybe trickle some WD40 and let it penetrate for a while ?
I haven’t seen a Burke close up, but does the mouthpiece end of the whistle overlap the tone hole section, as on most brass whistles?
If so, finding a whistle with a slightly wider bore than the tone hole section (but not larger than the mouthpiece end) would probably help.
Turn the larger whistle upside down, feed the foot end of your Burke inside it, and give it a sharp shove. The mouthpiece end of your Burke should be brought up short against the end of the tube, which should be enough to break the seal that’s been created by breath condensate. It might take a few attempts to get it all the way off.
It’s the same technique used to remove the plastic heads of old Generation whistles, where for that particular bore/head size, a Bb whistle is ideal.
If you’re worried about scratching the brass on the mouthpiece section of your Burke where it impacts the larger whistle, maybe try protecting it with a bit of plumber’s tape?
You might try chilling the tube. It might shrink enough to allow the whistle to come apart.
Thanks, I’ll try all that, John.