TromboneChat

Something kinda cool I'm prototyping, resin topped blanks. Doing a few just for some rigorous testing. Here's photos of the first one. Thus far I'm quite enjoying it, nice dark sound.

It looks cool!

Jeff,

What material did you machine for the cup top?

Posaunus wrote: ↑Tue Oct 04, 2022 9:06 pm Jeff,

What material did you machine for the cup top?

Slow cure foodsafe resin, poured and set for a week. I've done it in a different variation with excellent results, but the process just to make the blank took far too long to be profitable. If this bond is adequate, I'll be able to produce them.

I think you can readily purchase off-the-shelf polycarbonate rod stock in appropriate diameter, as Doug Elliott must do for his rims. Possible alternates: Delrin, ABS.

Posaunus wrote: ↑Wed Oct 05, 2022 9:34 am I think you can readily purchase off-the-shelf polycarbonate rod stock in appropriate diameter, as Doug Elliott must do for his rims. Possible alternates: Delrin, ABS.

Sure, but this is made as one piece and more than just the rim. Goes .75" into the mouthpiece. Plus, it looks sexy.

Looks snazzy!

Was able to optimize the full resin top with metal core method as well. This is a tenor or thin rim bass blank ready to cut.

Darn, you need an apprentice to teach that too.

trombonedemon wrote: ↑Tue Oct 11, 2022 4:01 pm Darn, you need an apprentice to teach that too.

Lol. Heres the final product

Is the (beautiful) resin cup threaded onto the shank?

Posaunus wrote: ↑Tue Oct 11, 2022 4:12 pm Is the (beautiful) resin cup threaded onto the shank?

Yup. There's a piece of metal thats set in the resin when its poured. That's whats threaded.

LIBrassCo wrote: ↑Tue Oct 11, 2022 4:56 pm

Posaunus wrote: ↑Tue Oct 11, 2022 4:12 pm Is the (beautiful) resin cup threaded onto the shank?

Yup. There's a piece of metal thats set in the resin when its poured. That's whats threaded.

To make sure I understand, you overmold the resin on the threads? Or do you thread both and join them?

(I always love the process nuances)

Cheers,
Andy

elmsandr wrote: ↑Wed Oct 12, 2022 8:32 am

LIBrassCo wrote: ↑Tue Oct 11, 2022 4:56 pm

Yup. There's a piece of metal thats set in the resin when its poured. That's whats threaded.

To make sure I understand, you overmold the resin on the threads? Or do you thread both and join them?

(I always love the process nuances)

Cheers,
Andy

Well since u asked....

I cut a piece of metal (bronze, brass, nickel silver, etc) to .7" diameter and 1.25" long. On the bottom it is threaded but not drilled past the threaded area. Then I make a wood disc thats 1.85" dia and .25" thick, to press onto the bottom on the metal core. This is used to center the metal in the resin, and provide a hard bottom to my makeshift mold. I then take a buttload (technical term) of blue tape and make a cylindrical mold out of it. At this point i mix up 105 grams of 2:1 resin, adding whatever color and flake tickles my fancy, stirring with a drill for 5ish minutes. After carefully pouring it into the mold, I run it through a bunch of vacuum cycles to pull the air out. Takes about an hour to get it all out. It then sits for 7 days, then is demolded. I screw it into a fixture, and cut the whole thing down to a working dimension.

It brings to mind some very old mouthpieces that were turned out of ivory.

Since you are doing semi-transparent version I think some embedded LEDs that flashed to sounds to be the next step.

No allergy issues with the metal flake?

hornbuilder wrote: ↑Wed Oct 12, 2022 1:43 pm No allergy issues with the metal flake?

If it was a concern I can simply not use any. Just a little color and good to go.

hornbuilder wrote: ↑Wed Oct 12, 2022 1:43 pm No allergy issues with the metal flake?

And here's what that looks like. No coloring or metal flake.

Very cool.