As per my previous notes, the external heat sinks on the system, as per the instructions, were not big enough on the exterior of the module to provide adequate cooling. My solution was to water cool the peltiers, however I need a water block that is big enough to span two peltiers.
Below you can see what we are building today.
Index
Step 1 – Drill main cooling channels
Step 2 – Drill first cross channel
Step 3 – Drill the rest of the cross channels
Step 4 – Drill and tap and fit the grub screws
Step 5 – Drill and tap and fit the barbs
Tools Required
Drill Press
11mm drill
5-6mm drill
Drill and tap to suit barbs
Drill and tap to suit m6 grub screws
Loctite thread adhesive
Parts List
100x50x20 Aluminium block
2 x Water cooling block barbs
4 x grub screws
Loctite thread adhesive
Step 1 – Drill main cooling channels
A couple of things to take into account before you start. When you are creating something of this type, by machining a chunk of metal, it always pays to plan it out properly. I am as guilty as the next guy of just picking up some bar stock and going for it, but inevitably that leads to making something that either doesn’t quite fit, or just doesn’t work.
So, draw out what you are building and try to account for all eventualities. In this case there are a few traps.
1. Make sure that the first thing that you do is work out where the bolts are going to go that hold the water block down to the peltiets and heat sink. As per the previous instructions you will have 8 holes in the main heat sink block that at your disposal. I figured that I probably only needed the outside 4 in order to hold the water in place, so marked out the locations of where I needed to drill the holes.
2. You are going to need two large holes that run the length of the block, but dont come out the other end. They need to take into account the mounting holes that you just marked out. You want them to be in each corner as you can see in the model below.
In drilling a hole this large, it is best to use a pilot hole first. What I did was to drill 5mm or so into the aluminium block with the large drill so that I was sure that positioning was correct, then swapped to a much smaller drill. It was easy to position this smaller drill as the first large drill left the centre point.
TIP: make sure to use the depth stop on your drill press so that you dont break out the bottom of work piece.
Once you have drilled the pilot hole, you will probably want to go for a larger pilot hole as well. Once that is done, go for the final size. In drilling aluminium, you will probably want to use a lubricant to avoid the drill sticking. Aluminium lubricant is generally Kerosene.
One hole done, move the work piece over and repeat for the second hole.
Step 2 – Drill first cross channel
Now that you have both those holes drilled, clean up the work piece to remove all the swarf (waste metal shavings) from the holes and plan out where the cross holes are going to go.
I chose to have 4 cross channels, figuring that it was probably adequate to have two per peltier. You will want to draw the peltiers location on the block so that you can see how it is all going to go together in order to get the holes in the right place. If all else fails, make them evenly distributed and it should be fine as well.
Again, you are going to want to only drill most of the way through. You will go right through the first big channel and into the second, but no further.
Here you can see the first cross channel drilled.
Step 3 – Drill the rest of the cross channels
Once you have drilled the first cross channel it is simply a matter of drilling the other 3.
Once you have them all drilled give the bock a good clean to remove all the excess.
Step 4 – Drill and tap and fit the grub screws
Now that we have the cooling channels all drilled, we need to seal off the outsides of the cross channels. This will allow the water to flow through the block, in one large channel and out the other. In order to accomplish the sealing off, we are going to drill and tap the small holes and insert a grub screw.
I chose M6 sized grub screws but you can use whatever you can get or feel adequate.
You want to drill into the block for the depth of the thread with the recommended size drill for the tap that you are using. THis will mean drilling into the first large channel.
Tap the 4 holes next and test fit your grub screws. You should have a nearly completed water block at this stage, however the grub screws will not be water tight. In order to fix this get some thread adhesive. Loctite is a popular brand. You basically just coat the hole and the grub screw with the red fluid and screw them into place. It will take about 24 hours to dry, but when dry your block will be water proof.
Step 5 – Drill and tap and fit the barbs
To connect the new water block to the water cooling loop, you are going to need barb hose fittings. Again, these will need a particular sized drill and tap. Drill the holes and tap them to suit.
Screw in the barbs. If you have barbs with an ‘o’ ring, then you wont need to loctite them.
Drill hour mounting holes as you market previously, taking care to ensure that you wont drill into any channels and you are now finished.
An important step is to check the new water block for any leaks. Plug it into your water cooling loop and run it for an hour to see if any water leaks out. If it doesnt then you are ready to go and move onto the next step.
Next tutorial is to fit the water cooling system to the cabinet and mount the water cooling block to the heat sink.
