Lapping my CPU Cooler

[kdog154]

My current CPU cooler = Thermaltake CL-P0114 120mm Big Typhoon CPU Cooler

 

I bought a bunch of different sand paper grits (200, 400, 600, 800, 1000, and 1500). I started with the 200 and went up and down on the sand paper for a good while (ever now and then turning it 90 degrees and repeating).

 

Anyway, my problem is that the middle of the cooler doesn't seem to be flat like the rest of the cooler. It is obvious by just looking at it that there is about a penny size spot in the middle that looks completely different then the rest.

 

Should I just keep using the 200 grit until this goes away or is there something I am doing wrong?

[SpikeSoprano]

My current CPU cooler = Thermaltake CL-P0114 120mm Big Typhoon CPU Cooler

 

I bought a bunch of different sand paper grits (200, 400, 600, 800, 1000, and 1500). I started with the 200 and went up and down on the sand paper for a good while (ever now and then turning it 90 degrees and repeating).

 

Anyway, my problem is that the middle of the cooler doesn't seem to be flat like the rest of the cooler. It is obvious by just looking at it that there is about a penny size spot in the middle that looks completely different then the rest.

 

Should I just keep using the 200 grit until this goes away or is there something I am doing wrong?

 

That would depend on how deep the indentation is, if it is a flaw in the base and you keep using the 200 grit it could take the rest of the base down too much and it would ruin the base, sometimes it is better to just use a bit more termal compound to fill the bad spot and see if it cools any better.

[kdog154]

I'm not sure if the imperfection is too deep or not. The cooler is about 4-5 years old. The imperfection seems to be in the area where I applied the thermal compound on the CPU when I installed it.

 

Here is a picture for reference.

 

At first the area was like a "C" on the bottom of the cooler but I kept sanding it and now I am left with what the picture shows. I'm not sure if i should keep sanding it or not.

 

[SpikeSoprano]

You could hold a straight egde across the base(carpenters square or even a credit card ) and you should be able to see if it is indented much , if it is even right across the edge use the fine sand paper a little more and it should be good.

I looked at pics of that cooler and it is fairly thick so you could do quite a bit of sanding before you would take off to much, but if it is level with the straight edge it will be fine.

Edited August 6, 2011 by SpikeSoprano

[sticknstone]

The heatsink base will mate with the processor die. What is the processor die surface flatness? To achieve a flat heatsink surface then yes continue with the 200 grit paper till the concave is removed. The low grit papers are best suited for rough quick removal of the surface material. Do not use a carpenters square or a credit card as they do not have the fine straight edge needed to see the flat heatsink surface desired. Instead look for the tools machinists use. I am looking at removing the concave of my big water cpu block and have a vernier caliper that I will try out. The only paper I purchased is 200, 300, and 400 with a tube of polishing paste. I still have not located a grit higher than 400, but only checked one store. The sanding is coming along just fine.

[Boinker]

I would use 500 for bulk removal of meterial. After the hit is with 1000 and the. Use 2000 to finish it. As far as lubrication use soap and water. Ten strokes and rotate 180. Ten more rotate 90. The 180 and ten again and repeat that until you are satisfied with the surface you are looking at.

[SpikeSoprano]

The heatsink base will mate with the processor die. What is the processor die surface flatness? To achieve a flat heatsink surface then yes continue with the 200 grit paper till the concave is removed. The low grit papers are best suited for rough quick removal of the surface material. Do not use a carpenters square or a credit card as they do not have the fine straight edge needed to see the flat heatsink surface desired. Instead look for the tools machinists use. I am looking at removing the concave of my big water cpu block and have a vernier caliper that I will try out. The only paper I purchased is 200, 300, and 400 with a tube of polishing paste. I still have not located a grit higher than 400, but only checked one store. The sanding is coming along just fine.

 

I beg to differ, a 12 inch carpenters square is very straight and smooth, not everyone has machinist tools laying around at home and if your stuck a credid card had worked for me a few times, the op's cpu base is not large. IMHO of course.

[Drdeath]

Lapping a heatsink yields maybe 1-2 degrees and is not worth the effort imo. The CPU is a different story.2 to 6 degrees is the norm depending on how concave the processor is...... also remember. The majority of heatsinks are flat........ in these cases it is futile....

 

When lapping, you do not need 2000 grit.1000 grit will be fine and temps will not differ from 1000 to 2000 grit. By the time you hit 1000 grit, either the CPU or heatsinks will be flat if you lapped it properly. Those tiny tiny scratches from 1000 do not add to the temps.

Edited August 8, 2011 by Drdeath

[Drdeath]

I would use 500 for bulk removal of meterial. After the hit is with 1000 and the. Use 2000 to finish it. As far as lubrication use soap and water. Ten strokes and rotate 180. Ten more rotate 90. The 180 and ten again and repeat that until you are satisfied with the surface you are looking at.

 

Your method is too time consuming. The first cut should be done with 400 grit. You do not have to rotate every 10. Every 50 is fine and 90 degrees. You can visually see the first cut easily as far as the progress. After you do 400 grit, use 600. Then 800. Last cut of 1000 grit is all you need. No water or soap is needed. Lubricants slow the process down. If you want a baby smooth mirror then you keep going to 2000 and use water like wet standing on the final pass.... but soap and water is ridiculous and slows it down like mentioned.

[beeiilll]

Here is a guide for lapping to give you some added info:

 

http://www.overclock...guides/lapping/

 

 

A utility knife blade makes a good straight edge as it is 2-1/2" long and works well with a light to see any imperfections on the surface as you do the lapping.

I always use some form of lubricant for lapping or polishing as it helps to carry away the removed material as well as make it easier to control the pressure/ speed/ alignment of whatever you are working on.

The more time and effort you put into it, the better the end result. Take your time and take breaks if needed and you will see an excellent end product.

Edited August 9, 2011 by beeiilll