Thanks for the info guys, appreciate it
So a few questions:
1) So I should be looking at PETG?
2) What size tubing is best?
3) Any particular brand fittings better than the others?
4) What tools do I need? Is there a recommended kit?
1: I can't bring myself to use it, so it's a no from me.
Acrylic is clearer but by an almost imperceptible margin. However the properties that make PETG easier to work with are, for me, the very reason not to use it. PETG softens at a much lower temperature so you need less heat to get the bend in, but that temperature is also the same as hot coolant in a failed loop (60 degrees) and there are tales online of PETG tubes deforming and popping out of the fittings, dumping coolant everywhere. At least with acrylic you only have a dead pump to contend with if somethings gone wrong and spiked your coolant to that temperature.
Also PETG has a slightly flexible nature to it so you can - by a tiny amount - yoke tubing runs into place if your measurements are a teeny bit out, but that puts pressure on the fittings and you run the risk of leaks. Also, there are some coolants that don't work with PETG so you'll need to check that as well.
Acrylic has none of these issues but it does mean you need to be bob on with your measurements and be a lot more careful with your heating.
2: preference; the bore in a fitting is always 10mm regardless of tube size. Aesthetically big tubes look great in big cases, little tubes look great in little cases. The bigger the tube though the bigger the bend radius is going to be i.e. you can't get as tight a bend. But of course you need to make sure your fittings are the same size AND in the same units (e.g. don't go using 1/2 inch tube in a 12mm fitting because it will leak, and it won't fit in a 13mm fitting).
3: it seems that anybody who does metric fittings are the better quality. Circumstantial perhaps but there seem to be more horror stories about Monsoon and Primochill fittings than anybody else, and they're imperial. So you're looking at Bitspower, Barrow and Alphacool. Apparently the new Thermaltake fittings are incredible, but I won't give those thieves my money.
Barrow have 13mm and 14mm OD options too with the tubing to match. Alphacool do 13mm fittings as well.
4: you'll need a hacksaw and small mitre block for acrylic, but PETG can be cut with a pipe cutter. Both will require a pipe deburring tool to clean up your cuts and get the required chamfer in place. Some fine grit wet n dry paper is great for that extra polish on the chamfer (strongly recommend).
As for bending itself, you'll need a cheapo heatgun to apply the heat and unless you have some crazy-ass requirements perhaps play it safe and buy in a mandrel kit to make your bends (but do check that the generated bend radius isn't going to be too big for your tubing run). You'll also need a silicone insert to support the tube as you bend. That pupper needs to be fractionally smaller than the ID of the tube, so 9.5mm OD for the insert for 10mm ID tube. Plenty around but it might be best to get one from the same place you get your tubing (although there is a premium involved). I use a 9.5mm silicone fuel hose for Shakmods 12mm acrylic tube because I have some insanely tight bends, and solid inserts just don't bend tightly enough for me.
I think Alphacool do a bending kit with everything you need.
