Building a fiberglass upright bell for a 20J

[royjohn]

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,
royjohn

[timothy42b]

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.

[The Big Ben]

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.

[timothy42b]

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.

[Donn]

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.

[PlayTheTuba]

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.

[timothy42b]

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.

[royjohn]

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.

[royjohn]

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...

[PMeuph]

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

[PMeuph]

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.

[royjohn]

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...

[PMeuph]

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

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

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" target="_blank

[royjohn]

If the upright bell is $1200 (plus shipping?) then I'd have over $2K in the horn and I would wonder whether it might be better to just find a BAT with an upright bell...it might depend on whether I will be able to get rid of my flat F when the valves are aligned...

[Donn]

It seems to me though that there are persons of creditable reputation, who have seen 20J series tubas that do not have the flat F.

[royjohn]

Double N Donn wrote:

It seems to me though that there are persons of creditable reputation, who have seen 20J series tubas that do not have the flat F.

Oh, c'mon, Donn, bloke is just being his cheery self...although it is true that some well regarded repair folks have claimed that a properly de-dented, non-leaky, valve-aligned Conn 2XJ does not have the flat F. My leadpipe has been de-dented by a local tech and I did tape most of the big joints to see if that might help (a 20J is pretty with all that blue painter's tape decorating it), but so far the F is still equally flat whether played open or 1-3. It seems odd to me that 1-3 doesn't seem to help at all...I'm going to get one of those little USB cable cameras and see if the valves are out of line...they do have new felts, but that doesn' mean they are aligned...I'm not sure if there's anything else I might do...I'll bet using a blokepiece would fix it right up...

[royjohn]

Wow, great minds think alike, I was just wondering if there was an alternative bell I could use...

[Art Hovey]

I asked Dick Barth about purchasing one of his bells, and he said no.
Same answer for a valve section.

[The Big Ben]

I asked Dick Barth about purchasing one of his bells, and he said no.
Same answer for a valve section.

I'm sure he would rather sell the complete instrument.