Originally posted by bowman1964
dabit you would never notice a leak though the hose,by the permeation rates.but it depends on a lot of varables,
OK, if you say so, I believe.
What about temperature range. I intend to use those hoses for ethane transport. And I hope to reach the -100C evaporation someday. This doesn't mean that the hose must transport -100C vapour, but -80C would be a reasonable guess.

you can buy convoluted stainless steel tubing here in the states for gas opperated appliances.comes in 30" lenghts i have found so far.
I have been looking for them in The Netherlands, without luck. Here they seem to use exclusively a rubber kind of gas hose.

The big advantage of that hose would be that I could braze it directly onto the 3/8" copper pipe, right?

Also, bending radius of convoluted SS hose is not bad. Usually somewhere around 140mm dynamic and 40mm static.

i can find rates for rubber based hoses.which for a 3/8 id hose with r134a has a permeation rate of .07 pounds per year @212f
That sounds acceptable, but barrier lined rubber hoses are not by far as permeable as (P)TFE hoses.