Wow, thank you for the information! It'll take me a bit to digest what you said as I'm not familiar with the terms.
The CPVC was a proof of concept "Prototype" as I called it, but I fully expect (at least I hope) you are right and the CPVC will melt. I'll have to watch the prototype closely. The final, if the idea works would be copper.
Interesting. I have yet to see this u-shaped copper in glass idea you have pictures of. What is this system called? Obviously my idea is not a new one huh?
"very different coefficients of expansion of copper vs. soda-glass"
'll have to look up the data, but the copper should not come in contact with the glass. I hope to have a resin plug sealing the pieces together. The thermal expansion is a very good point however and needs to be looked at.
"without a copper-> glass penetration"
OH! so the open end of the glass seals to the black manifold in your picture as does the copper. What a good idea! I'll have to consider this.