This is my first attempt at custom water cooling and there were lessons learned. Oh yes, there were lessons learned. I read and re-read the PrimoChill water cooling instructions. I watched and re-watched oh so many YouTube tube bending videos. Nothing authoritative is complete. And neither is this...
1st lesson: Do not underestimate your ignorance or overestimate your own talent. Tube bending has a steep learning curve. Single bends can be trimmed to flush and square nicely, but double bends must be 100% accurate because...
2nd lesson: Imperfect bends cannot be re-made into perfect bends (mostly). Clear PETG tubing will show every last flaw. E-ve-ry-thing. PETG will mar on accidental contact with almost anything. It seems to never be cool enough to not be scored. PETG tubing cannot (generally) be reheated and un-bent/re-bent. Reheating can cause small bubbles to appear in best case and huge gross, warty bubbles in worst case scenarios. Any inadvertent torque applied will cause odd twist patterns to appear in the tubing.
3rd lesson: Double check your bends for square. Your bending jigs are almost certainly not 100% correct. My 90 degree bending jig, in truth, turned out to be a 85-ish degree jig. Enough to cause my single bend tubes to not be square and my double bend tubes to be binned. Slight, I say again, SLIGHT heat can be applied to relax the bend and bring into proper square. I used a drafting t-square attached to a board to jig my 90 degree bends. Apply slight heat, just enough to the bend to cause it to relax a bit, place GENTLY against the t-square and fix with a few spritzes of water from a spray bottle.
4th lesson: Prevent leaks always.
a) Your tubes must contact o-rings squarely with no gaps.
b) Everything plastic is covered in release oils and everything metal is covered in machining oil/coolant. O-rings are covered in mold release oil and will slip under pressure. The inside of tubes will be covered in oil from the extrusion process and if clear of that will be covered in soap or oil from the silicon insert used during bending. Clean this out or the o-rings will slip.
c) Disassemble everything and wash it inside and out. Wash everything with dish soap and scrub with a toothbrush. Be mindful of disassembly order, take pictures if necessary.
d) Do not pinch o-rings on re-assembly. Do not lose o-rings. If it started with a seal, it must end with the same. It is a bad thing if you end up with extra o-rings after reassembly where previously there were none.
e) Clean, dry, dry fit, pressure test, fill with prep solution, test again, drain again, disassemble to completely empty of prep solution, reassemble, pressure test again then finally... fill with coolant.
5th lesson: Double bends are the devil. Try only if your confidence is absolute or you neglected to buy 90 degree fittings. I fell into the latter rather than the former.