Make a Water Block Out of a Heatsink for Less Than $20!




About: I'm a university student from the good ol' USA! I'm studying Electrical Engineering and loving every second of it! I've always been a maker, I love applying the things I learn in school to my projects, and l...

With CPUs and other computer components becoming hotter and more powerful faster and faster; traditional air cooling methods are no longer efficant enough to cool these components.  Another way to cool components is water cooling, but this can be very expensive, which is why, in this Instructable you will learn how to create your own highly efficant waterblock for $20 or less!  I made my waterblock to cool a 168 watt thermoelectric junction 

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Materials and Tools

For this project you will need:
-a 120V plug-in drill
-some plexiglass or lexan sheets#
-a heatsink with wide spread fins
-JB weld#
-2 brass (or plastic) screw-in barbs#
-a hacksaw
-a thin sharpie*
-a centimeter ruler (this is a MUST I'm living in the U.S.A and even I'm using one; they're more accurate)*
-a large quick-clamp
-a piece of wood with a straight edge
-a utility knife with a sharp blade*
-various drillbits*
-vinal tubing to match the barbs*
-a file*
-SOS pad*
In total all of my materials were easily accessable from Lowes and costed $13.00
* item is not pictured
# item was bought
NOTE: plexiglass and lexan are not the same thing, lexan is stronger and more expensive, but when I say plexiglass I mean lexan.

Step 2: Planning Water Routes and Cutting Out Heatsnk

Before any serious work begins, the waters route inside the water block must be planned out.  Take your time, you will only have one shot at getting it right.  Try to plan a path that does not obstruct the flow to much or create little areas where bubbles could form and become trapped.  My design utilizes many holes drilled perpendicular to the fins.  Once your design is done, cut out the heatsink and drill or cut until the heatsink fits the design. 

Step 3: Cutting Plexiglass and Cutting Barbs

Now measure all of the demensions of the heatsink and trace them onto the plexiglass with the sharpie.  use the wood as a guide to score and cut the plexiglas.  Most of the time,, the threads on the barbs will be too tall, use the hacksaw to cut them down, make sure they are the same hieght. 

Step 4: Polishing the Bottom

use the SOS pad to polish the bottom of the heatsink, go in a back and forth motion until a good shine is achived.  To test the integrity of the polish: put a drop of water on a piece of plexiglass, press the heatsink onto it and flip it over.  If it sticks you're good, if not polish more.

Step 5: Dry Fit and Gluing

Now dry fit the plexiglass peices, if they are too big use the file to shape them up.  if they are too small, re-cut them.  remember measure twice cut once :)  after you know the pieces are the right size, begin JB welding them into place.  Be sure to sand the to parts being joined.  It is best to do this part in two steps.  Also try to keep the plexiglass clean, it makes of a better overall look when it is finished.

Step 6: Leak Test

Connect your water block to your water pump/source and let it run for a long time (24-48 hours).  If it dosen't leak great!  If it does, then add more JB weld.  Mine leaked and the entire right side came off! D:  I re-glued it and it seems to be holding up well.

Step 7: Final Thoughts

It came out much better than expected
did a very good job of cooling the TEC
didn't obstruct water flow
can't beat the price! :D
I love comments, so leave one! :)
total cost: $15 :)

EDIT: 8/19/2010   ok so this thing was a flop, it broke again, except this time on the opposing side, I dont feel like fixing this every time.  So I made a soda can waterblock, and haven't had anything go wrong yet :P   



    • Indoor Lighting Contest

      Indoor Lighting Contest
    • Make It Fly Challenge

      Make It Fly Challenge
    • Growing Beyond Earth Maker Contest

      Growing Beyond Earth Maker Contest

    50 Discussions


    1 year ago

    I think a good revision, would be to negate cutting holes in the fins. Then, seal the inside in a manner that would direct the flow of water to travel the furthest distance over the heat sink. This way you are attempting to remove heat from all parts of the heat sink fins. Remember, water is just like air, is just like electricity, path of least resistance is always preferred.

    Example, move the heat sink fins to one side of the block, leaving about 2mm of space for water to flow out the end of the fins opposite of the inlet. Next, ensure that the inlet tube has a sealed wall equally separating the distance between the inlet and outlet tubes. This seal should run the length of the heat sink.

    Next, position the outlet tube parallel to the inlet on the other side. Then create a seal that encloses the inlet and outlet tubes so the flow of water has to travel into the slits of the fins down to the bottom of the heat sink before traveling laterally.

    I think this may help remove more heat and provide a better heat capacity to the overall design.

    pc stuff 3T

    3 years ago

    Great Idea

    Thanks :)


    3 years ago on Introduction

    This is neat and all, and I suppose 5 years ago this might have been a cheap alternative, but today you can buy a 42x42x12mm aluminum cpu waterblock for $10. A cheap motor and radiator, plus hoses and mounting tools, will set you back another $30, for a $40 full watercool system. If you've got a beefy video card, tack on $10 - $17 to cool that thing (depending on the number of GPUs), and your total sits at under $60 for a full CPU/GPU watercool setup.

    1 reply

    Reply 3 years ago

    I made this because I was young and unable to order things on the internet. To be 100% honest I would never reccomend watercooling to anyone, it's a novelty really.


    4 years ago on Step 7

    I've been experimenting with water cooling high power LEDs, and this is a freaking awesome idea.

    If you're using acrylic sheets, you should consider a solvent-based glue made for plexiglass, like they use for DIY aquariums and the like. It essentially welds the plastic together, and makes for really strong containers.

    Considering the quantity of heatsinks I already have, this saves me a righteous bunch of money. Thank you!

    1 reply

    Reply 4 years ago on Step 7

    Huh Somehow I never thought of that. I made this a while ago and I've since learned about that exact adhesive, But for some reason I never connected it to this project. Thanks for the comment I might just have to make one of these again!


    4 years ago

    you can buy some cheap containers for less than 5$


    6 years ago on Introduction

    the best way to polish a heatsink is to use a lot of qtips and googone, after about 10 minutes of scrubbing it is VERY VERY clean.


    6 years ago on Step 6

    this was a really good 'ible! i plan to use something like this for a high power led. but i think silicone would be better as a glue. that what glass aquariums are built with :D

    1 reply

    Reply 6 years ago on Step 6

    search suda can water block, it's a much better design than this

    mr. clean

    8 years ago on Introduction

    Thanks for the polishing idea, i polished a square aluminum spacer for use with a TEC, after polishing heat transfer was greatly improved!

    1 reply

    7 years ago on Step 7

    Awsome Build, going to use this im my system. :D


    8 years ago on Step 7

    i think it would be better if you see if a friend that has metal shop can make you a cheap waterblock for like 3 bucks out of scrap metal, then all you need is a metal filer to shine it up and give it a curve then itl look sweet. thats my plans to do, make one for my graphics card, northbridge, and processor

    3 replies

    Reply 8 years ago on Introduction

    Ya I don't know anybody that could do that, it would be nice though. I made a soda can water block.....maybe in the next billion years ill get around to posting a picture.


    8 years ago on Step 2

    Leave the burrs-- more surface area to transfer heat to the liquid. That is, unless they seriously impede the flow of liquid.