Alignment of Cork in Spit Valve

[bobroden]

I’m wondering if anyone else has addressed this issue.

The cork in my horn’s spit valve is not centered over the hole from which spit comes out of the slide. Please see the photo. The cork seems to JUST cover the hole, so I’m not losing air, and the horn plays fine, but I think I get more dripping than I otherwise would because of the way these pieces are aligned.

Note that in the picture, it looks as if the cork is not centered in the metal holder (the cap in which it sits), but it actually IS centered. It’s kind of an optical illusion because of the shapes of the pieces.

Now imagine for a moment that there was no cork at all in the cap. I think that in that case the cap would be pretty much centered over the hole when it came down to meet the hole. This would be because, in the absence of a cork, the cap could travel farther.

So it appears to me that the alignment of the two pieces didn’t really take into account the thickness of the cork that would go between them, resulting in the kind of alignment you see in the picture. I’m wondering if perhaps I should take a cork and try to reduce its thickness in some way so that the cap part would travel farther down before the pieces actually meet.

I can’t be the first one to notice something like this. Is there a standard approach to addressing it, or does anyone have any suggestions?

[BGuttman]

I think part of the problem is that you have the wrong size cork. There are 10 mm corks and 12 mm corks and it looks like you have a 10 mm glued in when you should have a 12 (which my fit in by friction without need for glue).

[ghmerrill]

I agree with Bruce. I don't know about the fit by friction part. I've never seen a water cork that didn't have adhesive. I prefer the Valentino synthetic cork version: https://www.jlsmithco.com/product/valen ... key-corks/.

[bobroden]

I think part of the problem is that you have the wrong size cork. There are 10 mm corks and 12 mm corks and it looks like you have a 10 mm glued in when you should have a 12 (which my fit in by friction without need for glue).

I can see why you would think that, but I don't think that's correct. In the picture, it looks as if the cork is a little small relative to the metal holder, but that's because the cork is offset by the thickness of the metal holder. When you turn it over and look at it, there isn't a gap between the cork and the metal, so I don't think a cork any larger would actually fit.

[ghmerrill]

The nipple looks bent or squashed a bit on one side. But the cork sure does look under size as well. It should fit really tightly into the cap.

[bobroden]

The nipple looks bent or squashed a bit on one side. But the cork sure does look under size as well. It should fit really tightly into the cap.

The horn is a Holton 65, made in 1951. I can't find a specification for the cork size, but it seems like the right size -- it sits flush up against the metal all the way around.

[elmsandr]

Duck bill pliers.

Of course, cork size has to be correct, and you have to account for some wear…. But most every slide I see in the wild could use this adjusted, tbh.

Heck, all but two of mine could use improvement.
1) a slide with a different style water key,
2) an M&W slide.

As weird as it is to say, that M&W water key is fit so perfectly, it amazes me when I touch it. It feels weird to even notice it, but it is actually noticeable.

Cheers,
Andy

[ghmerrill]

I can't find a specification for the cork size, but it seems like the right size -- it sits flush up against the metal all the way around.

If it's flush, then it is likely the right size. As I say, that nipple seems bent to me. Getting it replaced (probably can't be straightened) would then solve your problem. Or you can try to carve your own water cork that's a bit bigger and will seat well against the existing nipple. Mushroom-shaped water key corks used to be made (mostly European, I think). I can't seem to find any sources for them now. Or maybe you could carefully file the top of the nipple to better mate with the cork -- but that might end up making things worse.

[greenbean]

Well, my diagnosis of your water key is that the cork is too thin. A thicker one will align better. But... it really doesn't matter; if it seals, it seals. Have a tech tell you their opinion next time you are at the repair shop in... Oakland.

[brassmedic]

It's a common problem. I see many trombones that for whatever reason were built that way. Drives me nuts. You could try cutting the cork with a razor blade to reduce its thickness. Then the key will close further and thus move further out. The cork will be at an angle relative to the nipple, but if it's natural cork you can push it down over the nipple so that it forms an indentation that will make it seal. Otherwise, take it to a tech.

And, as mentioned, something looks odd about the nipple. Looks like it sits too high on the inside. But maybe that's just an optical illusion.

SpitValve.jpg

[CharlieB]

Don't overthink this.
Simple fix.
The cork is too thick.
Insert a strip of stiff sandpaper between the cork and the nipple and sand the cork until it centers up over the nipple. The more you sand, the more the cork will travel sideways (to the right in the picture).
By sanding the cork in place against the nipple, you assure that the mating surfaces are parallel and will seal
properly. You will end up with a slightly wedge shaped cork, and the cap may not center exactly over the nipple, but that's just cosmetic.

[bobroden]

Don't overthink this.
Simple fix.
The cork is too thick.
Insert a strip of stiff sandpaper between the cork and the nipple and sand the cork until it centers up over the nipple. The more you sand, the more the cork will travel sideways (to the right in the picture).
By sanding the cork in place against the nipple, you assure that the mating surfaces are parallel and will seal
properly. You will end up with a slightly wedge shaped cork, and the cap may not center exactly over the nipple, but that's just cosmetic.

Sincere thanks to everyone who offered thoughts on this. It's really helpful to hear players' ideas and not have to rely solely on one's own thinking!

I decided to do as CharlieB suggested, with the sandpaper. Used 60 grit, which is pretty coarse and stiff, but seemed about right. Took just a few minutes, but reduced the amount of cork sticking out, which let the key come down a little farther, which in turn created a little margin at the edge of the cork, as you can see in this new picture. Still airtight, but now with this additional margin I'm hoping it will be less leaky.

I'll try and remember to report back on how it goes after playing this way for a few days.

Thanks again!

SpitValve2.jpg

[CharlieB]

Lookin' good.