home brewed
For what it's worth, instructions below.
I ended up making it myself as nothing appropriate was available.
I'll post photo's once the final product has dried because the last step was bonding the flared tubing to flared 024 sheet to act as the flange.
I didn't realize my flare kit went as high as 5/8 OD (actually goes much higher). So I started by making several 6061 tubes of 1" long and flared the ends.
To create the flare on the 024 I used a wood backing drilled to 3/4", drilled the flange to 1/2" undersized. I placed a 3/4" drill bit in the drill press, centered the drill bit over the hole/wood backing. I lubed the bit and the flange with corrosion-x and by hand counterrotated the but while using the press to create the down force, forcing the flange to form into the 3/4" hole.
The results are actually very nice.
As a final step used a 3/4" ID plastic tube to coax the entire assembly to conform better and then proseal the tube flare to the flange flare.
It could be done better obviously with a flare tool that could do flat surfaces. But with what I had available the results are great.
Cheers.