Slide bumpers, cork barrels

[Macbone1]

How do you know when it's time to replace the bumpers in the cork barrels? I have two instruments that sound rather loud on the slide return. Not the really loud clank of metal on metal but still kind of loud. And what about the practice of only putting one bumper on? Would both be better?

[BGuttman]

My rule of thumb is if you have screwed the slide lock pawl (arm) all the way in and it still doesn't lock the cam you need new bumpers. Of course if you have no slide lock, this test doesn't work.

If you are talking about putting bumpers in only one of the two cork barrels, my thoughts as an engineer is "don't". You will introduce a bending moment on the slide brace each time you ram the slide home. This can't do any good.

[Macbone1]

Thanks much Bruce. Slide locks still work, so far so good . I had read about the one cork barrel approach on this forum somewhere, and was rather surprised.

[ithinknot]

I don't play against the bumpers, so the loudness is irrelevant to me. I replace if they're crumbling, if they might be harboring smells (buying a used horn with a stanky case), or if there's too much play above the slide lock.

Bruce is right from a theoretical perspective - though I imagine the risks are minimal compared to the forces introduced every time you go anywhere near 7th - but why "ram the slide home" anyway?

The advantage of only doing the lower side is that there is a noticeable difference between directly and indirectly smacking yourself in the teeth, though neither is recommended.

[Macbone1]

Thanks ithinknot. I normally don't close the slide 100% either but there's always a risk of a "thunk", which can come through on recordings. I hardly record anymore so the point is moot.