You mentioned that you desired to make the 45degree multi level thumper out of glass and stainless steel. Chemist, if you remember,warned about the uneven coeficient of expansion not being the same. This is a reasonable concern, but I remember my days in the hot glass studio, and I recall that thin copper can be embeded in glass with LESS (notice that there can be some) breakage than any other metal. Sometimes the piece of art would crack ,and sometimes not.
I also recall that as a student jewler, that I used copper for my base in producing enamel jewelery.
The lowdown on the skinny is that if you have your heart set on a metal and glass multi stage thumper, it might be good to try to manufacture it out of copper and glass.
The cutting partway through glass tube procedure(even with the relatively easy 90deg cut) requires both good nerves, and some expensive cutting equiptment. The drilling of return lines wont be easy either, as the tube will be weakened from the 90 degree cuts near the hole.
The cooling tube at the last stage wont transfer heat very well through the glass tubing either...copper has better transfer for heat/cold.
I'm not trying to warn you away, but it wont be easy.
Sugest that you make an all copper one first.
I still think that the design you have has good potential.
good luck
