Agreed.
Clearly extruded is totally adequate for some projects, but not so good for others.
One specific issue I've run into is crazing around any fittings run through the tube. For ex when making a reactor or skimmer, if good sized (1/2, 3/4" fittings are installed in the side of the tubing, I've seen major crazing develp very easily. (crazing being when the material forms many little cracks looking almost like a spider web). On the other hand, with cast tubing I've drilled, tapped and installed fittings quite tight with solvent, and had no sign of crazing whatsoever. (I'm not sure how well it would work using Uni-seals, these may put a lot less stress on the tubing and be better/safer than threading and or using solvent to attach fittings?)
On the other hand, if you don't drill holes in the tubing, but rather run any fittings through the top and or bottom, IME extruded seems to work fine.
In the end, take into consideration the work your putting into any project and think of what those hours are worth to you. Personally I'm very reluctant to use extruded for anything more substantial than a simple chamber with not fittings going through the tube, skimmers exct, I'd shell out the $ for cast - if nothing else, cast is IME WAY more forgiving.
Any info on the design your thinking about? Got a drawing or an example your basing your ideas on?
