What to do about tight bends?
 

I'm working on assembling my setup right now, and I have some really tight bends that I need to deal with. What do I do about these?

I used copper elbows can get them from the pluminb section from any hardware store.

Coolsleeves or equivalent.
http://www.swiftnets.com/products/coolsleeves.asp

Coolsleeves work great, but a nice spring will do the trick too ;-)

Where does one find lengths of springs that fit the OD of the tubing we use?

I wish I knew. All I have in this size range are plumber's tube-bending springs, sized at copper pipe O.D.s, and bought at "tool" prices. They're flared at the ends, for easier insertion. I take them off of course after bending the copper tube.

The sharp turn of a store-bought elbow is a bit restrictive, but maybe you could form your own gentler bends in soft copper with a steel spring in hand.

You probably could but at that point it's probably better to just use whatever flexible tubing you happen to be using. I used five 90 degree elbows on my system for space and non-kink reasons, 2 copper 3 vinyl.

There ought to be some way to get a radius smaller than bent tubing and larger than cast elbows. Maybe PVC conduit for electric wires is adaptable?