Cleaning the heatsink

Next i took a water spray bottle and mixed it with 5 parts water to 1 part washing up detergent.  I used this to apply to my wet and dry paper for plenty of lubrication during the lapping.

I applied the detergent to the 400 grit paper...

This is the heatsink i used.  It's a Thermalright HR01+

You can see the bottom of it before i started, quite bad really; you can see the machining marks in it.

So i started to go to work, i started with a forward and back motion as it was easier...

You can see the nickel base starting to dissapear and the copper showing through...

This was taking longer than i thought, i'd been at it for nearly an hour already, so time for a quick tea break :)