I'm from Italy, sorry for my poor english. I express myself with photos, hope will be clear my idea. One photo show an old hot water bottle, roughly 100 years old. I opened it carefully, and now I have 2 halves. My idea is to use the wooden guitar body as a megaphone. The brass bell stays on 4 brass pins at some distance from the wood bottom. Not screwed, but free. It stays in place pressed by the strings. Wath do You mean ?
Post Scriptum. I touched by error the "like" button. It's not my habit.
So, essentially you want to use the lower half of the brass water "bottle" (or "bell" as you called it) as a resonator and you plan to build your own guitar around it. I think that the Can Jo Consortium is perhaps the wrong discussion group. Fortunately, there are a couple of discussion groups on building resonator cigar box guitars as well as a discussion group on building your own boxes (bodies) for your guitar. These folks might be better prepared to answer your questions than folks who primarily deal with canjos. Here are some links for you...
Resonator Cigar Box Guitars
My advice is to first look at photos and discussions on CBN (this website) to see how other builders are attaching their resonators. Many of these builders use purposely designed resonator cones that are attached to the sound board with perhaps a dozen screws and which use a wooden biscuit to link the bridge to the center part of the resonator cone. However, many other builder use a variety of other objects re-purposed for resonators including paint can lids, small cans (like tuna fish cans), dog or cat food (metal) bowls, automobile hub caps, license plates, and many other things. Your "bell" definitely fits in this second group. The important question to be answered is how to attach your particular resonator to your sound box in such a way that it will be both solidly mounted and free to vibrate. The vibrations of the strings have to be transferred to the resonator and this is usually done via a bridge and (sometimes) a biscuit.
I'm sure other folks here will respond to your inquiry, and I expect most of them will have more experience building resonator guitars than I do. My first (& last) attempt had a slight miscalculations as shown in this photo...
I'm as a baby in the toyshop. I have seen (better studied) roughly 6000 of the 90000+ photos, it is a very creative input. Thank You, Rand, I will follow your advice. I was a glassmaster, I make stained glass windows all over for 30 years, must give up becouse infermity. Currently I am employed in a big iron fudery, but all of my creativity has no way out. I have payed 4000€ for one bow of my son(violinist) when I discovered CBG...........
Hey thats an easy fix ! did you ever finish it ?
Hi Piht Bull. No, I'm on the way. Actually I'm working over the 2 bells, tryng to equalize them. Next step will be a couple of simple "test bed" for searching the best distance between the bells and the wood bottom. I will copy a scheme from an "esotheric" Hi-Fi loudspeaker baffle, where that distance is critical for reaching a maximum reinforcement of low frequency.
Here You will find the physics principle ( in italian) and a very clear drawing of that baffle
Ciao Marcus ! Yes, but I refuse to do a "normal" cbg why I have to pass the neck thru the bottle, and also why the two "bells" have an ashtonishing sound, very loud, that the complete bottle has not. And, most of all, this way I'm having a lot of FUN. Today I have soldered a sheet of brass to close one of the two bells, then I measure the sound level with a phonometer. I'm a 62 young boy.