How to Mod a Senfu Waterblock

Radical mod on a failing waterblock – Aaron McBride

Lets start off by saying about a year ago, I purchased a Senfu Watercooling Kit with the money I had received for writing the top article for (you guys are the best). Sadly to say, this kit did not work too great at all. Sure – if you want to go with watercooling just to have it, you have something that’s worth it for the price.

As for performance, I’d stay away from this kit. A month or so ago, my block began to leak around here (pic blew) where the red line is drawn:


A month or two after I had the block, it started to get LOTS of build up of a calcium deposit/white jelly looking stuff in between the “fins” of the block, which was an absolute PAIN to clean out.

Turns out the block was basically rotting from inside out. The aluminum base on the inside was turning back in between the fins and was becoming VERY weak. The plastic top around where it started to leak was turning from a hard plastic to a rubbery texture. I ended up purchasing a Danger Den Maze-4, which I am A LOT happier with.

Supplies Needed

  • Hacksaw
  • Sandpaper
  • Metal file(s), preferably one rough one and one that’s semi rough
  • Dremel (don’t need but is reccommended)
  • JB Weld quick dry/set (kind that drys completely in about 30 minutes)
  • Drill + bit

First Mod

For the first mod, you will need the drill & drill bit. The drill bit needs to be just SLIGHTLY smaller than the ID of the hose barb. What you want to do is drill into the hose barb:


The red arrows inicate where you need to drill for those of you that dont really understand what I am talking about

If you look closely into the barbs, there isn’t an open hole for water to flow through – it is a hole with lines going through it which reduces water flow, which is bad. After you have the holes in the barbs drilled out, it’s time for the next mod.

Second Mod

The first step to this is to take apart the waterblock, if you haven’t already. This is where you will need the sandpaper, hacksaw, files and maybe the Dremel to make life a bit easier. Below are the steps that you need to follow in order to do this mod:

  1. Take apart the waterblock.
  2. Using the hacksaw, cut along the red line in the following pictures; cut all the way across and cut off the top of the fins.



    In case you do not understand the pictures, here is where you want to cut the fins off the block. If you look at the block, it has “indents” in the fins on the top and the bottom for some goofy, odd reason. You want to cut the fins off at the BOTTOM of the BOTTOM “indent”. This will cause the fins to then only be a few mm high.

  3. Using the metal files, file the top of the fins left on the block to even them out.
  4. Using the sandpaper (I used 100 grit), sand the top of the fins that you just evened out with the files to make them nice and smooth.

  5. What’s left of your waterblock should be the base with fins that are now a few mm high, rather than an inch or so.

THIRD MOD Continued on page 2…

Third Mod (Optional & Recommended)

This mod is up to you but I would highly reccomend it. Once you have the fins cut, you can do the following things:

A. Put the block back together like normal and use it without much of an increase in performance, because you STILL have the top that’s an inch or more high, but your fins are a few mm high.

B. You can cut the top down to be a bit better than the fins and re-attach it to the block using JB Weld.

If your choice is A, don’t bother reading what’s below unless you want to read it for pure knowledge, etc., but other than that, it would/will be absolutely pointless for you to read it. For those of you that choose B, continue on – the steps for the third mod are listed below:

  1. Look at the plastic top and you will notice, around the barbs on the outside of the block, there are little lines which form a square and are pushing out from the block a few mm. The bottom line of this square will be used as a reference mark of where to cut the top.
  2. Get the hacksaw and cut the top of the block in two separate peices. You want to cut between 5-6mm below the bottom line of the square so you have room to sand, etc.
  3. Once the top of the block is cut into two sperate peices, you will be dealing with the top portion (portion with the barbs), although I do not reccomend throwing away the bottom peice….It can still be used for something (you never know).
  4. Sand and or file the edge of the block where you cut and try to make it flat as possible. For example, if you set it down on a table you want all the sides to be touching the table; you don’t want it to wobble around. It is VERY important that you get this as flat as possible.
  5. Once the top is cut, sanded and so on, fit it onto the block to be sure it fits well, is flat and so on. Once you have a fit that you feel is good, mix up some of the quick drying JB Weld (well that’s what I recommend/prefer anyway…the original kind is probably just as good). Apply it around the base of the waterblock where the top will touch it/come in contact with it. View the picture below for a general area of where I’m talking about.


    You want to spread it as close to the fins as possible and at least passed where the blue seal/”O” ring would be.

  6. Once the JB Weld is spread about the base of the block, attach the top to the block and push down, making sure the base and the bottom of the top come in contact with each other and the JB Weld.

  7. Mix up more JB Weld and spread it ALL around the edge of where the block and the top meet – you can never use too much. If this is not done with enough or good enough, the block WILL LEAK. Once done, spread it/smooth it around the edges with your finger and give it a good 30-45 minutes to dry – then it should be ready for testing. So far, I have had mine testing for about two hours and still no leaks. Below is a pic of the final product which you should now have:


If you have any questions, please email me. Thanks to for the pictures.

Aaron McBride

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