Lapping Copper Based Heatsinks
by DaZZaBoY


'Lapping' or fine sanding your heatsink is an effective way of making 
your CPU cooling unit more efficient by removing microscopic 
imperfections and corrosion from the copper and ultimatly reducing 
load temperatures. This is definately a bonus if you run a lot of 
3D games and applications on a regular basis and a MUST if you 
overclock your CPU. 

This project is aimed at the Thermaltake Volcano range of copper 
based heatsinks, but will work with any other copper based unit. 
It is a simple and cheap job to do as you only need the following 
stuff: 


* 3 different grades of wet/dry sandpaper (between 400-1500 grade)
* Metal polish and a clean cloth
* Some H20 - free from any tap!
* About an hour (or two) of your time.
* A lot of patience! 


Important: Before you start sanding you will (obviously) have to 
remove the fan from the heatsink assembly so you are just left 
with the main block. You don't want to knacker your fan now do ya!


1. Most heatsinks after a good bit of use will look like this. 
The copper base isn't 'perfect' when the unit is in brand new 
condition, so you can imagine how inefficient a cooler is when 
it is covered in thermal grease/thermalpad leftover, finger 
prints and general corrosion!

Give the base a rub with a clean cloth to remove any leftover 
thermal compound or gunk before you begin sanding. 


2. Lay your heaviest grade (lowest numbered) sandpaper down on 
a flat, sturdy surface and wet the paper with a small amount of 
water. Place the heatsink block copper side down and whilst 
applying some downward pressure, twist the block left and right 
continuously. Keep the action consistent and apply even pressure.

Every so often, give the base a wipe with a cloth and then 
continue sanding... 


3. When you have sanded the initial 'gunk' from the base and 
have an even smooth finish, wipe off and continue the wet 
sanding process with the next (higher grade) paper. When you reach 
the second sheet you don't have to apply as much pressure on the 
block, as the aim now is to start removing scratches and polish 
instead of removing material as we did with the rougher grade paper. 

At the end of the middle grade paper, you should have something 
similar to Pic 3 


4. The last grade (smoothest - highest grade) paper will be the
most time consuming.After the wet sanding process with the final 
paper, wipe off and dry sand with a fresh sheet of the same grade. 
The dry sanding won't scratch the copper as much and will set you 
up nicely for the polishing stage.

Carry on dry sanding until the copper is scratch free and you can 
roughly see your reflection in it. (Hopefully :o) 


5. After a buff off with some metal polish the image in Pic 5 is 
ideally what you should see.

If you have no metal polish then just use your breath on it and
polish it that way. 


The more time you put into this project, the better the results 
will be! Apparantly, if done properly, a drop of 5-7oC can be 
achieved in CPU idle temps after 'lapping'- but these temperature 
changes will become more apparant when the CPU is under heavy load. 

When I did this project myself, I actually swapped my Gigabyte 
mainboard for a slightly newer revision model, so I was running 
a better temp sensor before I tested the results of the improved 
cooling. When the PC reached normal running temp my unclocked 
XP2600 CPU was showing an improvement of a massive 13oC cooler 
running. Sorted, one chilled out machine!!! 

[Pics were scanned from PC Extreme] 

End.