Next episode: Going on a bender!
Having half of my parts for my cooling experiment together it's time to get my hands dirty: I follow Elon Musk's engineering mantra to always start with the hardest problem - and in my case that's bending that heat pipe into shape. A) because the radii are tighter than anything I have found as a recommendation, and B) because I have never done that before and understand that heat pipes like to buckle (and then fail). At this point, I'm not sure whether this will work out - we shall see!
To get this right, I first need to cut my cold plates into shape - if you scroll up a bit to my "design" post, you get an idea of what I'm after:
One and a half cutting disks later I look at this:
As you may have spotted already, the VRM cold plate on the bottom edge of the image is different from my original design - I realised that I'm not constrained by the motherboard's footprint with the S4M having some slack between case and board, and decided to route the pipe around the outer face of the CPU power socket. Saves me one kink - but I'm still stuck with a 10mm radius.
After about half hour of careful massaging I get this- the tube is a bit short but, overall, usable:
I figured that using the grooves in the aluminum blocks as a mould to keep the side faces of the pipe from buckling outwards when bending helps keeping the profile in shape, so I "roll" (actually that's more like hard pressing) the pipe through the groove while slowly bending both ends upwards over a 10mm profile:
Next, I need the chipset block to bend my pipe to measure - time to rip my cheap CPU cooler apart:
Under the clamp, as expected, I find my block soldered to three 6mm heat pipes. Now, rather than trying to heat this assembly with my soldering iron (I'll probably never get it hot enough, heat it asymmetrically, or worst case, get the heat pipe to burst...), I'll improvise a little: From what I have read about heat pipes, they tend to explode when overheated - so they are typically soldered using low temperature bismuth solder, with a melting point of just 138 degrees celsius.
The solution is in my kitchen: I adjust my hot air oven to 138C precisely using my multimeter's temperature probe...
...and hang the cold plate into the grate with the rest of the assembly pulling on the tube with it's weight.
If I have my physics correct (and my bet on the bismuth solder is a winner), it should eventually drop out of the cold plate.
And BOOM - 4 minutest later I get a satisfying "plong" from the oven and find my separated cooler in the baking tray, with no pipes exploded (that would have been a different sound!).
In turn that means, I could also solder-in heat pipes in the oven using bismuth solder paste... not really planned, but an option now should cooling performance be insufficient.
With a pipe bender I can now tackle a slightly more generous 25mm bend to get the VRM heat pipe's end to it's desired destination in the chipset block:
So far, so good!
As you can already see in the image above, I have cut some slots to the VRM block on the right...
...to fit in some 6mm nylon upstands to fix it to the motherboard.
Some more grinding...
...and the block fits neatly onto the upstands...
...which means in turn that I can now fix it with a couple of sprung screws and some washers.
Now, for fixing the VRM block, I'll need to cut the modded CPU block's bracket to fit:
After transferring the drawing to the bracket...
...I go through another cutting disk to bring it into shape, ...
...drill a pair of holes for the screws to hold it in place,...
...with the result looking pretty much like what I had in mind:
Last thing to to is to machine a cross bar form an old aluminum heat sink - I want to use it to press the bracket down evenly. The remaining fins work as flanges and should make it reasonably stiff.
To mount the heatsink onto the x570, I use 9mm M3 nylon standoffs in the original mounting holes, and stick 5mm standoffs onto the original heatsink's 4mm rubber feet using double sided tape to make for a level support plane.
With pipe and chipset block in...
...I can mount the bracket and cross bar for a stable fit.
The block should now hover about 0.5mm over the x570 - I am still waiting for 1mm thermal pads to arrive, as well as for the 5mm heat pipes to connect the offset heatsink and fan.
Quite obviously, the VRM heat pipe wants to be longer - I have ordered a 250mm long one now that should fit precisely, so eventually the one you see here will be considered a dry run and replaced by something that actually fits!