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Building a fiberglass upright bell for a 20J

Postby royjohn » Thu Jul 05, 2018 3:14 am

I wonder if anyone here has had any experience building fiberglass bells for tubas. I was thinking of building an upright bell for my Conn 20J. I think I could find measurements somewhere and I think I could build a form with ribs and such from thin plywood, but I'm a little stumped about the ring to fit into the collar on the Conn. I guess I would have to fabricate a ring out of brass (I do know how to solder brass) and then somehow attach the fiberglass bell to that, but I'm not too sure how that would go. Rivets?

Grateful for any discussion from those familiar with working with fiberglass. I know this can be done because there is a gent in the UK who makes these for about L200...however, shipping would be L275, which kills the deal ($630 for the bell + shipping). He says there isn't any bad effect on the horn's tone from the fiberglass bell.
Thx,
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Re: Building a fiberglass upright bell for a 20J

Postby timothy42b » Thu Jul 05, 2018 7:48 am

You don't need to build a form.

You already have one.

Use your existing brass bell as the form. Use lots of mold release! Do a wet lay up fiberglass on your bell. Remove. You now have a mold for the actual bell. Now you can make as many as you want, until your DIY mold wears out.

The ring? Epoxy it onto the new bell, after a layer or two.
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Re: Building a fiberglass upright bell for a 20J

Postby The Big Ben » Thu Jul 05, 2018 9:29 am

timothy42b wrote:You don't need to build a form.

You already have one.

Use your existing brass bell as the form. Use lots of mold release! Do a wet lay up fiberglass on your bell. Remove. You now have a mold for the actual bell. Now you can make as many as you want, until your DIY mold wears out.

The ring? Epoxy it onto the new bell, after a layer or two.


However, he does not say he has an upright bell. That's why he wants to make one.
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Re: Building a fiberglass upright bell for a 20J

Postby timothy42b » Thu Jul 05, 2018 11:23 am

The Big Ben wrote:
However, he does not say he has an upright bell. That's why he wants to make one.


Quite right, I failed to read for comprehension. My bad - if he had an upright bell he wouldn't have to find measurements.

Still, if he could borrow an actual bell it would make this process simple. That's how people make fiberglas boats, too - making a female mold first then the actual boat inside it.
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Re: Building a fiberglass upright bell for a 20J

Postby bloke » Thu Jul 05, 2018 11:33 am

I wonder if somewhat might have a badly-cracked-but-not-bent-up one (not being used) that could be loaned out for use as a mold, were this person to pay r/t shipping/handling and promise to return it "clean" ?
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Re: Building a fiberglass upright bell for a 20J

Postby Donn » Thu Jul 05, 2018 12:48 pm

timothy42b wrote:Still, if he could borrow an actual bell it would make this process simple.


Well, maybe. Fiberglass would have to be significantly thicker than the original brass, right? I guess you'd really want to match the interior, not the exterior, and the closest approximation would probably be to lay the glass on the outside. He wants a brass tenon in there, which is the only sane way to go, and it seems to me that's ideally set in the glass during the layup. Given approximate dimensions I bet he can make an adequate mold, out of cardboard or building insulation foam or whatever material he likes, and the precise geometry is the least of his worries. How to make that tenon is a very good question - I think classically, they're milled from stock, but that would be pretty costly in a one-off situation; much cheaper to sacrifice a bell-front bell and remove its tenon.

Doesn't shed a lot of light on it, but Carbon Fiber instrument manufacture might be an interesting topic from 2007.
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Re: Building a fiberglass upright bell for a 20J

Postby bloke » Thu Jul 05, 2018 12:57 pm

I would probably build the fiberglass on to the exterior on a Conn brass bell (so that the interior of the fiberglass would be less than 1/32" larger than the Conn brass bell's, rather than (if built on the interior of a Conn brass bell) around 1/8" smaller.

There are old 22K (fiberglass version of 20K) male collars floating around out there which offer extra receiver space to accommodate the thickness of a fiberglass bell...and yes, the early 22K sousaphones actually featured FIBERGLASS (not plastic) bells.

Am I thinking wrong, here?
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Re: Building a fiberglass upright bell for a 20J

Postby PlayTheTuba » Thu Jul 05, 2018 1:15 pm

Back when I was senior in highschool in the 2009-2010 school year my highschool bought brand new set of King sousaphones. In one of the sousaphones they mistakenly shipped a Conn 20k bell. Before the Conn bell was sent back I took that bell and put a Conn 20j that our school owned and it fit really well. Is possible to order just a tenon from Conn-Selmer? Or if it is possible is ordering a tenon by itself very expensive? Seeing as a lot of recording/bell-front tubas without upright bells, people can make bells for them without sacrificing a recording bell in the process. Just curious. Although getting a tenon from a used bell will probably always be cheaper.
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Re: Building a fiberglass upright bell for a 20J

Postby timothy42b » Thu Jul 05, 2018 2:07 pm

For the section that is cone shaped, layup should be easy. The flare gets tricky.

Years ago I tried making a trombone bell of papier mache as a test before trying fiberglas. I made a male mandrel out of Styrofoam and masking tape, like your plan to layup on the outside of a Conn bell. (I think that's a good idea, it will be easier to start with a smooth inside surface.)

What I found was that a flat material like paper strips will align easily to a cylinder or cone, but a flare is different, it gets real tricky. It can be done but isn't easy the first time.
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Re: Building a fiberglass upright bell for a 20J

Postby bloke » Thu Jul 05, 2018 2:08 pm

Conn-Selmer has tenons (sousaphone) which will fit the (2XJ tuba) body, but only which accommodate sheet brass.

Those which accommodate (thicker) fiberglass (those which they manufactured for their 22K fiberglass short-action sousaphone) are long-long out of production.
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Re: Building a fiberglass upright bell for a 20J

Postby royjohn » Thu Jul 05, 2018 2:21 pm

If you search for Nightingale Trumpets on Facebook, Brian Robson's page will come up and there are some pix of a Conn upright bell on the horn. He also has a website, which I can't find right now and it does show pictures of a nice brass tenon attached, so he is either fabricating them or (I suspect) getting them somewhere. I"m assuming they are available from Allied or somebody.

Making the bell on an existing upright bell sounds like a great idea, but I think the chances of borrowing one for such use are almost nil. I'd expect to have to measure one carefully and then build some kind of form on which to build the bell. I understand that the upright bells are build a little narrower than the recording bell and that this helps the sound of the instrument some, too...this is just what I have read somewhere from someone who got an upright bell. I understand the Kanstul upright bell is a little smaller.

Now that I consider all the work involved, the $$$ for the brass tenon and formwork and fiberglass and resin (there would be a lot of it), $400 for a Kanstul bell doesn't sound so bad...but then there's the shipping, etc....I am not flush with cash right now, so we'll see down the road.
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Re: Building a fiberglass upright bell for a 20J

Postby YORK-aholic » Thu Jul 05, 2018 2:21 pm

Ah, you mean like this:

Fully finished:
http://www.nightingaletrumpets.co.uk/?page=viewproduct&ID=116


Some finish work required (cheaper alternative, with you doing the finish work):
http://www.nightingaletrumpets.co.uk/?page=viewproduct&ID=117

Perhaps a group buy to make the shipping more reasonable?
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Re: Building a fiberglass upright bell for a 20J

Postby royjohn » Thu Jul 05, 2018 2:33 pm

A group buy is tempting, but the price he quoted me a few years ago was L200, which is $265 at today's exchange rate. I don't know whether that was finished or unfinished. when you consider shipping and possibly finishing, the Kanstul starts to look good, but I haven't checked their current prices yet...I guess I will be making a few inquiries and getting back here later, if someone doesn't beat me to it... :D :D :D
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Re: Building a fiberglass upright bell for a 20J

Postby bloke » Thu Jul 05, 2018 8:19 pm

Not including shipping, it appears as though they are about $100 more now, but that may (??) include confiscatory taxes to which you are not subjected.
Since the $2XX days, we have suffered value-destroying practices, in regards to fiat money.
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Re: Building a fiberglass upright bell for a 20J

Postby PMeuph » Fri Jul 06, 2018 7:00 am

bloke wrote:Not including shipping, it appears as though they are about $100 more now, but that may (??) include confiscatory taxes to which you are not subjected.
Since the $2XX days, we have suffered value-destroying practices, in regards to fiat money.


Add an extra 100 quid for a finished bell. So current price in USD for a finished bell is +/- $600. (potentially with VAT)

http://www.nightingaletrumpets.co.uk/?p ... uct&ID=116
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Re: Building a fiberglass upright bell for a 20J

Postby bloke » Fri Jul 06, 2018 11:42 am

PMeuph wrote:
bloke wrote:Not including shipping, it appears as though they are about $100 more now, but that may (??) include confiscatory taxes to which you are not subjected.
Since the $2XX days, we have suffered value-destroying practices, in regards to fiat money.


Add an extra 100 quid for a finished bell. So current price in USD for a finished bell is +/- $600. (potentially with VAT)

http://www.nightingaletrumpets.co.uk/?p ... uct&ID=116" target="_blank" target="_blank


Looking at that, it seems to me as though, price-wise, they have found the perfect fence-walking price-point:
- not no-brainer stupid-cheap
- not absolutely unaffordably would-make-no-sense-to-pay-that too-high

bloke "Were I to REALLY want one of these (which I would never want, but whatever...), I would much rather pay $750 - $800 (with shipping) than to attempt to make one myself (requiring - very likely - three to eight "learning curve" attempts...particularly as I don't like displaying "semi-failed attempts at doing things" in public).

bloke "...and the brass collar is not 'free', either."
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Re: Building a fiberglass upright bell for a 20J

Postby PMeuph » Fri Jul 06, 2018 4:15 pm

My experience working with fibreglass is limited, but the three things I picked up are that there's a learning curve to working with it, it's nasty stuff and it's not cheap in small quantities.

In sum, I don't disagree with Bloke.
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Re: Building a fiberglass upright bell for a 20J

Postby YORK-aholic » Sat Jul 07, 2018 1:06 am

royjohn wrote: $400 for a Kanstul bell doesn't sound so bad...


Kanstul quoted you a price of $400 for one of their bells? :shock:

That is a lot lower than I’ve been lead to believe.
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Re: Building a fiberglass upright bell for a 20J

Postby royjohn » Sat Jul 07, 2018 1:17 am

I'm not sure if I heard that was their price or dreamed it or what. I have an email in to them (called them at 9:30Am their time and the recording said they were closed) asking for a current price quote on the bell. And, yes, IDK why I wrote that, because I do think that is way too low. I'm guessing $600 to $900, but it might be more than that...I'll post the quote here when I hear back from them. I visited the factory several years ago when in SoCal. Very nice people and wonderful horns, some of which I got to play. We tried to go back and take the factory tour, but they were at NAMM and weren't giving tours. I would have loved to have met Zigmunt before he passed. Next time I'm out that way I will take the tour.

I wonder if anyone here has a Kanstul upright bell for a Conn 2Xj horn and could report on how it works for them... :?: :?: :?:
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Re: Building a fiberglass upright bell for a 20J

Postby PMeuph » Sat Jul 07, 2018 6:50 am

YORK-aholic wrote:
royjohn wrote: $400 for a Kanstul bell doesn't sound so bad...


Kanstul quoted you a price of $400 for one of their bells? :shock:

That is a lot lower than I’ve been lead to believe.


I've also been lead to believe that it was over $1K. (I have $1200 in mind, but can't remember where I saw that) here's a topic that mentions the over $1k price.

viewtopic.php?f=2&t=70958
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