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Can someone sell me (or refer me somewhere to buy) a length of rotary stop bumper material? For tuba, of course...

I just use 3/16" rubber o-ring. people say it breaks down over time, but they last me years.

LeMark wrote: ↑Sun Nov 08, 2020 10:32 pm I just use 3/16" rubber o-ring. people say it breaks down over time, but they last me years.

Perfect! I will do that tomorrow.

I almost exclusively use and install silicone bumper cord, the kind referred to as "pencil eraser." JL Smith and Ed Krause (part 372B-250 for 0.250" diameter) sell it in different diameters and usually by the foot. Neoprene is more susceptible to lubricants and will cause it to harden and become brittle. The silicone cord has nice cushion and doesn't bounce too much. Most tubas will use the 0.250" size but some have cork plates with smaller diameter or opening that require 0.210" or even 0.187". It doesn't hurt to have some of each lying around in case you stumble into another tuba that you must have.

The orange-colored stuff (recommended above) is best, but this might be about the cheapest (when postage is factored in...)

https://www.ebay.com/itm/Belt-4-pack-fo ... 1197994253

I prefer to "stuff" ("roll", I guess...) material that is too large into cork plates, and - with a really sharp (first two or three cuts) single-edged razor blade cut a nice flat strike surface out of the bulging out "blob".

I'm raising my hand and admitting to this:
In an emergency, I've driven around the corner to the dollar store, bought ten pencils, and removed their erasers.
I told the (local) person to bring their instrument back (n/c for the eraser-bumpers), but - two years later - they told me those things were still fine.

This is what I was told to get and where I was told to get it. I have used "almost" 6 inches of it. I still have enough to do my tuba, all my friends' tubas, all their friends' friends' tubas... You get the idea.
https://www.amazon.com/gp/product/B00V4 ... UTF8&psc=1

I use Silicone cord available in several sizes from McMaster-Carr. This stuff does not break down from anything!

With the "pencil eraser" stuff, is it better to get the regular or the softer cord? Less bouncy is good.

Doc wrote: ↑Mon Nov 16, 2020 2:01 pm With the "pencil eraser" stuff, is it better to get the regular or the softer cord? Less bouncy is good.

I buy the 50 and 70 durometer red silicone from McMaster-Carr. I use more of the 50 durometer material and prefer it on my own horns.

Dan Schultz wrote: ↑Mon Nov 16, 2020 7:20 pm

Doc wrote: ↑Mon Nov 16, 2020 2:01 pm With the "pencil eraser" stuff, is it better to get the regular or the softer cord? Less bouncy is good.

I buy the 50 and 70 durometer red silicone from McMaster-Carr. I use more of the 50 durometer material and prefer it on my own horns.

Do you recommend a diameter (for the 1969 Miraphone 186)?

Every miraphone I've ever seen uses 3/16th, from the pre-180 F-tuba valveset that I pulled my valve off for my Eb tuba, the miraphone tenor tuba I owned for a while, to the 186's that the schools I teach for use

What ever diameter the “C” shapes are in the cork plates - and this can be easily measured, I roll the largest diameter material that I can manage into them. I nearly always take the cork plates off, wrap “cereal box” cardboard around their flat portions, and put them in the vice to do this.
When the open “C” shapes are more than a semicircle, they bite on the material better, and I can actually manage to get larger material into them. The larger the material I can manage to get in, the nicer the job, because I can cut the part (that bulges out) off into a nice straight line.
The larger the material I can manage to get in, the more manufactured the bumpers’ appearance is, when I’m finished.

Got some 50 in .210 and .275 on the way.

Doc wrote: ↑Mon Nov 16, 2020 8:30 pm

Dan Schultz wrote: ↑Mon Nov 16, 2020 7:20 pm

Doc wrote: ↑Mon Nov 16, 2020 2:01 pm With the "pencil eraser" stuff, is it better to get the regular or the softer cord? Less bouncy is good.

I buy the 50 and 70 durometer red silicone from McMaster-Carr. I use more of the 50 durometer material and prefer it on my own horns.

Do you recommend a diameter (for the 1969 Miraphone 186)?

The actual diameter is .273". I don't remember what size McMaster-Carr calls it. I buy 25 feet at a time and that quantity last me a while. Use a blunt screwdriver to force the cord into the stop plate and it will 'bulge' on the open side. Use an Exacto Knife to trim the 'bulge' so the alignment is correct. The alignment marks on Miraphone tubas are usually spot on as long as the rear bearing plate is properly aligned to the housing. Verifying alignment with a scope is best.

McMaster-Carr is your best source. I have better luck with O-ring cord stock bought in the mm sizes. Modern Miraphone is 6.5mm and no need to trim. To each his own, but I buy and install Buna-N as it seems to have the least bounce, not too hard but with a positive feel. Also Buna-N is a professional looking black instead of the color of a leftover Halloween Pumpkin. Yes, after 2 years the Buna-N starts to turn hard. But after 2 years, all played tubas need a bath and servicing with new bumpers anyway.
I keep a section of the old pumpkin silicone on hand for the rare person who asks for it, but with a selection of Buna-N cord stock in various sizes from 4mm to 8mm, I can find better fits to the various strike plates and alignment requirements. The stuff is so cheap, that we buy a new batch every 3-4 months.
That factory clear stuff is just too bouncy.

Hi strongly approve of Matt’s “So what if it wears out after a while?” attitude.

Otherwise, I’m reminded of people who are looking for some super long lasting valve oil (as if tuba valvesets could be compared to automobile engines) that they rarely have to apply to their valves…
I oil my instruments (actually) more to prevent them from getting coated with lime on the inside than I do to actually lubricate them.

Uh oh, am I too old school?

I still put cork on the back stroke to avoid too much bounce.