polish copper

[Rey overclocked]

ive need alot of the pots in this forum has mirror finishes on the bottom. ive been able to smooth out and flatten copper almost perfect but i can never get that reflection.

[Jort]

just look around for copper polish paste;) or metal polish

[Kizz]

Yep, even after sanding you'll still have these annoyingly visible scratches, but metal polish works wonders (well, it makes the scratches really small anyway :rolleyes:).

[Wstinkbait]

One should never use a polish or paste to lap a heat-sink. While it makes for a hansom shine it will imbed in the pours of the metal and decrease the thermal properties. Filling the pours and imperfections is a job better left to AS5 or a thermally conductive compound. 2000 grit has always left me with a mirror shine. Lap in the same direction avoiding swirls or cross grain hatches.

[BlueWonder]

Polish copper ay?! WTF's the problem with Australian copper! Lol.. sorry couldn't resist.

Lol, umm, looked up a guide on lapping? just google it. My bet is your not getting it down to a fine enough grain.

[[XC] moddolicous]

If you have the time and go up to ~5000 grit sandpaper, then you'll get that mirror finish. There are some compounds you can get that are equivalent to sanding @ like 5000grit (like what Kizz is talking about I think). Using a wax or something with only fill in the cracks where the thermal compound is supposed to go.

[Eldonko]

Brasso works to clean off residue from the oil in your hands and stuff.

[BlueWonder]

Brasso works to clean off residue from the oil in your hands and stuff.

Yeh worth a mention, I used brasso on my XP-97, removes any tarnish and grit and will give you a mirror-like shine. You might wanna use it ontop of your lapping.

[Kizz]

Yeah I was talking about abrasive finishing compounds rather than just aesthetic 'polish' - unless you clean that stuff off it will form a bit of a barrier as has been mentioned. But if you can get the paper it would probably be better anyways.

I'm sure I read somewhere that going over a certain amount of smoothness actually worsens the temps because the imperfections in the base do not fill sufficiently with thermal compound, and so the surface area contacting is quite small. I suppose in that respect you would then need to lap both surfaces insanely flat then compress them under a vacuum, or else use a really runny paste.

[spresv]

Sandpaper the bi@tch. If the surface is too rough you start off with an 600, then with an 800, and finally with an 1000. Then you polish it with the kind of paste they polish cars with. If you want high mirror shine whithout any pastes n stuff you should continue up to 2000 (1200, 1500 etc.)

I used up to 1000 with a sander, for about 10-15 minutes each, and then i polished it with a paste.

Before: http://img202.imageshack.us/img202/1199/img03262hv.jpg After: http://img202.imageshack.us/img202/113/img03398xz.jpg

[Wstinkbait]

It is also important to note lapping must be done on a perfectly flat surface such as a sheet of glass. Not counter tops, desktops workbenches or books. They are hardly ever flat. The point is to get the most metal to metal contact, not the highest shine. Leave that for your Mag wheels. The thermal properties of any paste, cream, wax or polishing compound (including Braso) will never equal that of a good medal to medal contact. It will imbed in the metal filling the tiny surface imperfections and luster like a diamond. But it will not transfer heat and is imposable to get it out without relapping the block. Less AS5 is needed on a polished block as well. Again metal to metal is better than AS5 to metal.

[Kizz]

It is also important to note lapping must be done on a perfectly flat surface such as a sheet of glass. Not counter tops, desktops workbenches or books. They are hardly ever flat. The point is to get the most metal to metal contact, not the highest shine. Leave that for your Mag wheels. The thermal properties of any paste, cream, wax or polishing compound (including Braso) will never equal that of a good medal to medal contact. It will imbed in the metal filling the tiny surface imperfections and luster like a diamond. But it will not transfer heat and is imposable to get it out without relapping the block. Less AS5 is needed on a polished block as well. Again metal to metal is better than AS5 to metal.

Amen to that. Tape the paper to some glass and lap in circles/figure 8's till it gets niice and smooth...then do it some more :p:

[wdrzal]

Make sure you by "wet paper" and use water when lapping.

[lawrywild]

Make sure you by "wet paper" and use water when lapping.

it's called Wet and Dry and yeh it's much better for lapping, when used with water it last FOREVER (well, sort of lol) and gives an even smoother finish.