LumberJocks

Tuba mouthpiece

  • Advertise with us

« back to Woodturning forum

Forum topic by kmetzger posted 01-12-2019 10:12 PM 737 views 0 times favorited 14 replies Add to Favorites Watch
View kmetzger's profile

kmetzger

177 posts in 2299 days


01-12-2019 10:12 PM

I’ve had an unusual request to make some tuba mouthpieces out of cocobolo. To shape the inside of the mouthpiece correctly, I need to make a mold. What material could I use to make the mold? https://www.youtube.com/watch?v=7-1td5f18QU at 1:07

-- Kim, Ajijic, Mexico, http://tinyurl.com/7w5fm25


14 replies so far

View TheDane's profile

TheDane

5670 posts in 4145 days


#1 posted 01-13-2019 12:29 AM

Bondo (auto body filler) might do the trick … just wax or lube the inside of the medal mouthpiece first.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View knotscott's profile

knotscott

8327 posts in 3857 days


#2 posted 01-13-2019 01:08 AM

FYI…Cocobolo is not skin friendly. I would think it’d be a terrible material to use as a mouthpiece.

Allergies/Toxicity: Notoriously allergenic. Reported as a sensitizer; can cause skin, eye, and respiratory irritation, as well as nausea, pink-eye, and asthma-like symptoms. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View Kaleb the Swede's profile

Kaleb the Swede

1904 posts in 2451 days


#3 posted 01-13-2019 02:36 AM

Is this just for display or something? I am a tuba player too and am just wondering what the thinking is.
Couldn’t think of any reason to have one out of wood.

Not trying to dissuade you at all, just wondering

-- Just trying to build something beautiful

View kmetzger's profile

kmetzger

177 posts in 2299 days


#4 posted 01-13-2019 03:45 AM

Here’s how one tuba player explains it. https://www.youtube.com/watch?v=BOKHwIk1KRM
And another one: https://www.youtube.com/watch?v=lbtV_PExlfI

-- Kim, Ajijic, Mexico, http://tinyurl.com/7w5fm25

View John Smith's profile

John Smith

1975 posts in 644 days


#5 posted 01-13-2019 02:45 PM

Kim, I second the auto body repair putty “Bondo” for the pattern.
or – whatever similar product you can find in your area.
liquid epoxy would work also if you can control the exothermic heat
generated by the product you use.

I harvested some Grenadilla wood when I lived in Guantanamo Bay
back in the ‘70s which is used exclusively for wind instruments such as the clarinet.
very easily turned on the lathe. does not hold an oil finish very well.
if you can find some in your area, I would recommend Grenadilla over cocobolo.
(and I think the Grenadilla is much more health friendly than the Cocobolo).
for examples, google: Grenadilla Wood Mouthpiece

.

.

-- I am a painter. That's what I do. I paint things --

View John Smith's profile

John Smith

1975 posts in 644 days


#6 posted 01-13-2019 05:02 PM

Kim – looking at your very nice projects, I would assume that you have
some two-part epoxy on hand. . . .
you could turn a piece of wood to fit 1/8” loosely inside the mouthpiece,
plug the hole in the stem of the mouthpiece with tape, use a “mold release”
with whatever you feel comfortable with, and pour in some epoxy and insert
the wood plug until the epoxy cures. that way, there is less epoxy used
and practically eliminates the exothermic heat that could jam everything up.
also provides more “hand hold” to twist it loose after the cure.
(seal the wood first to prevent it from soaking up the epoxy).

.

-- I am a painter. That's what I do. I paint things --

View kmetzger's profile

kmetzger

177 posts in 2299 days


#7 posted 01-13-2019 06:36 PM

Thank you for this, John. Everything is clear except for “mold release.” How do I pour the epoxy into the cup of the mouthpiece?

-- Kim, Ajijic, Mexico, http://tinyurl.com/7w5fm25

View John Smith's profile

John Smith

1975 posts in 644 days


#8 posted 01-13-2019 06:53 PM

mold release is any product that will form a barrier film between the epoxy
and the item it is poured into so it won’t stick. a layer of wax, spray silicone,
cooking spray, vaseline, etc. will work.
if you can melt some candle wax, that will work best. (just keep it as thin as possible).
a thin film of wheel bearing grease will also work ( just a little harder to clean up).
some people have used automotive and furniture paste wax, but, I have had some
bad issues with that. drill a hole in a 2×4 to keep the piece firmly vertical.
tape some paper around the top just to keep everything neat and tidy.

remove any bubbles then insert the wood plug, keeping it centered as much as possible.
put some weight on top to ensure it doesn’t try to float up.
the excess epoxy will flow out onto the paper. let it cure for at least 6-8 hours.
then twist it apart, clean off the mold release and you have your pattern to copy.

if you are going to be doing several of these, I would annotate the mouthpiece number
on the wood for future reference. (there are different sizes for different tones).

.

-- I am a painter. That's what I do. I paint things --

View Lazyman's profile

Lazyman

3881 posts in 1869 days


#9 posted 01-14-2019 12:58 AM

I don’t think that I would want to risk having to clean bondo off of someones mouthpiece. Since it is designed to permanently stick to metal, that could be a nightmare to clean off. In fact anything that needs a release agent would worry me. I would look at the modeling clays at a craft store like Michaels or maybe Crayola Air-Dry Clay; preferably, something that is water soluble. At a minimum, experiment with some old silverware or something with a nice silver or nickel finish on it to make sure that you don’t ruin it.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View kmetzger's profile

kmetzger

177 posts in 2299 days


#10 posted 05-16-2019 07:46 PM

Five months after the tuba player asked for the mouthpieces, he returned from touring and gave me the metal mouthpiece to work from. I didn’t make a mold after all. The idea of the mold was to make a special cutting tool to shape the inside. I decided I had enough reference points to get the internal shape needed. It was a success. He was happy with the sounds. He said the cocobolo piece had a stronger tone than the parota. I used a 11 mm round carbide cutter for inside the opening.

-- Kim, Ajijic, Mexico, http://tinyurl.com/7w5fm25

View John Smith's profile

John Smith

1975 posts in 644 days


#11 posted 05-16-2019 08:39 PM

wow Kim – very impressive !!
don’t you just love it when a plan comes together ?
so glad you got all the details worked out.

.

.

-- I am a painter. That's what I do. I paint things --

View SMP's profile

SMP

1336 posts in 387 days


#12 posted 05-17-2019 02:40 AM

Geez those would make Herb Alpert jealous. What did you finish them with?

View kmetzger's profile

kmetzger

177 posts in 2299 days


#13 posted 05-17-2019 02:40 AM

Many coats of CA glue.

-- Kim, Ajijic, Mexico, http://tinyurl.com/7w5fm25

View robscastle's profile

robscastle

6308 posts in 2686 days


#14 posted 05-17-2019 07:36 AM

Ask icemanhank he would be across these items, or if not, he will know somebody in the village thad does.

-- Regards Rob

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com