On my new to me 1963 Conn 72H bass bone I find I have to occasionally pull the F slide all the way out and turn the axe upside down to drain the "water" out of the small crook and stop the burbling. Tough to do on a tight stage. Have others encountered this problem? Has anyone put a water key on that crook? How did that work out? Any pictures?

Thanks for any and all inputs.

That happens on traditional wraps if you use the trigger a lot, especially if the horn is cold. I've had to do that with my 88h. It shouldn't happen once the horn is warmed up. That small bend doesn't leave a lot of room, I'm not sure you could get even a saturn in there. I'd suggest trying to get the horn warm before you start playing, if possible. This was really the biggest benefit of open wraps - all condensation drains down through the valve into the slide.

The Yamaha "semi-open" wrap has a second tuning slide specifically to empty water out with.

In this case, just find a way to work the water around back the valve. Or get it converted to open wrap. But that would mean more headaches when in tight spaces.