Water-cooling: Make your own copper adapters

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Hello Water-Cooling Enthusiasts ...

 

Meet 'Frankenstein', based on an earlier HEDT build from late 2018 but recently heavily modified. Having been replaced by more modern systems for primary use purposes, it now serves as a secondary work & play setup and backup in my home office... It can still throw quite a punch, especially for rendering and even light ML, what with 19,200 CUDA, 218 ray tracing and 1,416 tensor cores.

 

All that requires a lot of cooling, and since I love doing custom water-cooling, I like to share some tips on how to make your own 45 degree and 90 degree copper adapter turns - and also use copper tubing in conjunction with flexible tubing. I only treat the 'front' part of Frankenstein in this thread; there is also a Linux system on the back with a > rebuild AIO cooler that is by now in its 10th year...

    

  

  

 

At full boil, Frankenstein with its three GPUs and the Threadripper can peak at 1,700 W. That requires a lot of cooling, never mind that I like my systems to be whisper-quiet. Apart from five RX 360 rads, there are also three D5 pumps to keep it all circulating at good speed and pressure. That in turn means somewhat nightmarish tubing arrangements...in addition, I wanted to use as much rigid 1/2 inch copper pipe (ie. the long white horizontal tubes above) as well as elbows as possible, in conjunction with my favourite soft tubing (the only type I use) which is 1/2 ID -  3/4 OD PrimoChill PrimoFlex Advanced LRT. The copper elbows are either 90 degrees or 45 degrees - and only cost pennies. 

 

The question was how to combine the copper parts with the PrimoChill PrimoFlex Advanced LRT tubing. Simply sliding the soft-tubing over the copper will not work as both have the same inner diameter. What is more, the seal has to permanent, work with both the soft-tubing and the copper and survive both pressure and temperature swings and some 'mechanical movement' (below).

 

  

  

  

After some research regarding materials compatibility, heat and pressure resistance - and also trial and error - I settled on Oatey's HD PVC cement as the bonding agent. The real trick is to apply it only to the copper bits with about a 1/8th inch gap to the end of the copper piece. Then - wearing gloves as I found out the hard way ('duh' re. copper's heat transference rating) - you use a heat gun to heat the PrimoChill PrimoFlex Advanced LRT tubing and the copper pipe with the Oatey bonding agent on the copper  with the tiny gap as described. As the soft tubing warms up, it expands slightly and you can slide it over the copper pieces in question. As it cools down, it will contract and seal. Bonus: The Oatey agent is recommended to cure with a bit of heat anyway...

    

 

 

I have used this method for about five years now on something like none feet (total) of copper tubing and twelve 90-degree and four 45 degree elbows, and never had a leak, nor any problems with the cooling liquid itself. For extra safety, I add nylon zip ties on both ends of the joint(s), though hose clamps would also work. This should be done fairly soon after you slide the heated tubing over the copper parts, though. FYI, when I added the RTX 3090 Strix recently and made other substantial changes to the original build, I had to twist, turn and relocate these four-plus year-old home-made joints: No problemo