I have copper formers and plenty of experience with bending steel and copper so for the sake of $5 worth of stainless I'll at least give it a go. I really don't want to use any fittings underground especially mechanical compression fittings.Stainless, especially thin stainless is difficult to bend.
It tends to buckle and kink unless you have some very sophisticated metal forming equipment available.
Best bet might be straight sections of stainless pipe and brass compression fittings where you need to change direction.
i think if you get the coil itself preformed that you will not have many issues with the lines going to and from, but you would need to either weld the connections, solder them, or use compression fittings.I have copper formers and plenty of experience with bending steel and copper so for the sake of $5 worth of stainless I'll at least give it a go. I really don't want to use any fittings underground especially mechanical compression fittings.
This is why I'm thinking of forming them myself that way I can keep any connections above ground, I don't have a Tig welder on hand here and I'm unsure of adverse effects of oil on solder and even how well you could get it to adhere to stainless, so likely I'd go down the high pressure flange root as I have a flange tool and plenty of fittings aswell as generally being better than compression.i think if you get the coil itself preformed that you will not have many issues with the lines going to and from, but you would need to either weld the connections, solder them, or use compression fittings.
At this point I haven't tested but I'm not all that worried about temperature delta, the temp displacement is what I'm focused on.Have you determined the temp delta between where your coils are going to be? Is it going to be 80f and ambient is 120f or is the ground warmer and you have to dig deeper?