Heatsink lapping with toothpaste?

[Rexter]

I know that this trend has kinda died out over recent time, but thought i might give it a go for shits and giggles.

I have this old thermaltake silent viking, and its copper base has recieved quite a beating over the years and years of abuse. I thought i might give the old girl a boost so she can serve me for a few more years in my spare computer.
BUT the only thing i have around is some fine sandpaper (100grit) and standard colgate toothpaste.
I could use the toothpaste alone, but the matter is more of "how".
Google failed me, so how can i lap my old heatsink using toothpaste only?

 

[theJesus]

I have no idea about the toothpaste, but did you mean 100 or 1000 grit? Cuz 100 is not fine, it's the other way around.

 

[Basard]

add some sand to the toothpaste, you'll be alright

 

[Rexter]

I have no idea about the toothpaste, but did you mean 100 or 1000 grit? Cuz 100 is not fine, it's the other way around.

It feels fine to the touch, but i figured that 100 is not nearly enough as you said. Just wanted to underline my predicament

add some sand to the toothpaste, you'll be alright

I have some gerbil bathing sand lol

But can i start out with toothpaste right off the bat? And how should i do it to make sure it gets an even surface?

I figured i could find a piece of clean glass, a dab of toothpaste and rub the heatsink around in circular motions on the glass with the toothpaste?? Or is there a better method?

 

[erocker]

Toothpaste is not abrasive enough to lap your processor. The sandpaper you need is available at hardware stores or automotive stores.

 

[Rexter]

Toothpaste is not abrasive enough to lap your processor. The sandpaper you need is available at hardware stores or automotive stores.

Its the heatsink i want to lap, not the cpu

Upon further inspection the copper contact surface is not as much in a bad condition as i initally thought. Te only problem is that there is a lot of minor scratches around the cpu area, and a lot of thermal grease residue on almost the entire surface, that cant get off even with ethanol/alchohol. The copper plate still retains a mirror finish from factory, it just needs a bit of elbow grease to perfom well again.
Thats why i thought toothpaste would do the job as i had a lot of that within an arms reach.
So the problem was more like how to do it.

 

[OzzmanFloyd120]

The toothpaste has to have baking soda in it, because it's very mildly abrasive, it will act more as a polish at the end of your lap than the actual lapping agent.

 

[Tau]

start with 240 grit, then 400, 600, 800, 1200, then try toothpaste. and for 600+ you should be wetsanding. use the toothpaste at the very end for a mirror finish (polish)