TromboneChat

My bumpers on my Edwards are starting to become compressed. Is there a permanent, no-clickety clack solution to rotor bumpers? I remember Osmun advertized permanent rotor bumpers at one point, but I never had heard if these worked. Cutting, fitting, and setting bumpers should happen exactly one time ever in a perfect world l. I've done it on my horns more times than this, so life is not perfect.

Barring this, is there a way to uncompress the bumpers?

Doesn't the rotax have the clear polyurethane bumpers? IMHO those are about as close to permanent as you'll get.

No, mine came with blackrubber ones. I thought that the Osmun permo ones WERE the clear bumpers though. I wish that Edwards had used those.

The world is not perfect. Never will be. Every material wears in some way.

True. But mayhaps something better exists than vacuum fan belts?

Dude, stop whining. You can get 10 feet of it for about $10. At 1/4" per stop, 2 stops per valve, 1 change per year, that will keep you playing for about 240 years.
https://www.grainger.com/product/E-JAMES-Rubber-Cord-38G844

Quote from: harrison.t.reed on Yesterday at 07:40 AMBarring this, is there a way to uncompress the bumpers?

Soft jazz and maybe, like, a sidecar?

Bummer. I already do the bumpers the regular way using material like that, but I get it hyperbolica.

Anyone used polyurethane bumpers before?

Quote from: bubbachet on Yesterday at 11:46 AMSoft jazz and maybe, like, a sidecar?

 

I posted a diagram of an adjustable valve bumper I designed about a year ago on "Trombone Chat" which has disappeared. That, along with with a lot of great photos from other contributors showing the advantage of using a borescope to adjust valves properly, also disappeared.  This sort of material should be a part of a reference library, but apparently it just disappears into the void.  Anyway ---- it was a simple device that would make it possible to continually adjust your valve bumpers without ever really having to replace them.  Problem solved ! 

I'm not sure why all the pictures disappeared from Trombone Chat.  You might contact Bubbachet since he's the Technical guy on that Forum.  I know my avatar disappeared and I was unable to load any pictures to the site.  Big leak in the "Lifeboat".  You listening, Sliphorn and Bubbachet?

Incidentally, Harrison, you might be able to get the bumpers to soften a bit by soaking them in a concentrated detergent like Simple Green.

I never worry about bumpers. I take mine to Oberloh or
Ben and 10 minutes later, done 

I had softer silicone bumpers installed on a Conn Lindberg CL2000 valve, to replace the hardened and noisy rubber bumpers.  Bad idea!  The valve mechanism "bounced" off the resilient bumpers, causing a rebound effect, sort of like a stutter.  Fortunately, after watching me play, John Sandhagen diagnosed this and replaced the silicone bumpers on the spot with more rigid neoprene.  Problem solved in less than 10 minutes!  Thanks, John.   

Quote from: GetzenBassPlayer on Yesterday at 09:34 PMI never worry about bumpers. I take mine to Oberloh or
Ben and 10 minutes later, done 

Yeah? Getting to Ben is a chore when the ferries ain’t working.....

This is what I use:  http://www.jlsmithco.com/tubing-cord/silicone-cord-3ft.

Just get the right diameter.  I don't find it to be "bouncy" and it seems much more effective (and quieter) on my bass trombone than neoprene.  However, on my rotary valve tubas and euphoniums, I've always used the harder neoprene.

The silicone requires replacing a bit more frequently than harder stuff, but I really like it and it's easy to work with -- though not as "firm" as neoprene and so a bit more delicate to trim.

If you look on the Smith site, you'll see that there are several materials available, and in various diameters.

Hello everyone
Mike from Instrument Innovations.com when I designed my axial flow Infinity valve( also available as Instrument Innovation valves) I designed the rotor stop to have a radius to match the size of the bumper material . This extends the life of the bumper greatly. It also keeps it from indenting and cuasing misalignment of the rotor. It allows you to also use a lower durometer or softer material without the bounce effect keeping things quieter .

I am working on a new stop arm for my round rotors that will do the same. Thanks to imput from my technicians (JS  and BH on this one) there will be some other advantages also.
Thank you for your support
Mike

Finding the right material for a bumper is tricky.

Too hard and it clanks.

Too soft and it doesn't stop accurately.

For years we used cork.  But cork is a miserable material to machine.  Besides, it's getting expensive.

I like the idea of a fairly hard polyurethane; maybe 70 durometer or so.  It's firm enough to be accurate but soft enough to prevent clanking.  I haven't seen it in 1/8" "rope" though.  I've used Neoprene O-rings cut into cylinders for my rotaries.

Quote from: BGuttman on Sep 08, 2017, 07:59PMI'm not sure why all the pictures disappeared from Trombone Chat.  You might contact Bubbachet since he's the Technical guy on that Forum.  I know my avatar disappeared and I was unable to load any pictures to the site.  Big leak in the "Lifeboat".  You listening, Sliphorn and Bubbachet?

First I've heard of it -- I'll look into it.

Out of the few bass trombones I actually used daily for years I never had a bumper issue. Nothing to where I had to replace them. Only that the valve was slightly off and when I realigned them I also had a spare one or I just pulled one out while cleaning and replaced it. Do I have a magical aura that keeps valves working? Even valve action has stayed perfect. Just some lubricant whenever I felt like it. Nothing like regular anal retentive maintenance.

I bought my current daily bass trombone used and I never asked when the bumpers were replaced and I haven't needed to replace them still.

The softer materials may feel better and be a bit quieter,  but by being soft,  they will tend to compress easily and mis-align the ports if you press hard enough.
Also tend to deteriorate more quickly.

So easy to replace & adjust,  except for Hagman valves,  just get it done yearly!  Or more often depending on your playing needs.



Eric

The softer materials may feel better and be a bit quieter,  but by being soft,  they will tend to compress easily and mis-align the ports if you press hard enough.
Also tend to deteriorate more quickly.

So easy to replace & adjust,  except for Hagman valves,  just get it done yearly!  Or more often depending on your playing needs.



Eric