Polish with sandpaper or polishing paste?

[pdxrealtor]

Is there 'better' way to polish or is it simply a matter of preference?

I could do a 1000-1200-1500 polish job using sandpaper or I could use a 3 stage rouge polish procedure.... I prefer the paste and buffing pads for ease of use, but if sandpaper does a better job I'd consider it.

I used to polish metal injection molds and if I remember correctly for the mirror finish stuff we'd use sandpaper on the very large surfaces, and paste/diamond compound on the smaller projects. Been a long while though, so I could be off on that.

[William_Broadus]

Goggle Micro - mesh touch up stick, I'm very impressed by them for Pistol parts polishing.   YouTube has video on them as well

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[1SOW]

I prefer the paste and buffing pads for ease of use, but if sandpaper does a better job I'd consider it.

If you can keep the "flat" areas "flat" with buffing pads,  it should be fine.  I find the papers easiest to keep flat areas flat to just polish the high points of contact with the adjacent surface.

[pdxrealtor]

There's two styles of white buffing wheels I use, loose flap and solid. I think the solid type would accomplish the same thing as what you're saying about the sandpaper if I'm understanding you correctly.


I was more curious of the paste vs. paper effectiveness overall.

[1SOW]

For the initial polishing,  I like the fine papers on a hard flat surface--like glass or steel if possible.  For the final high polished look,  the wheel will work fine.   
With some caution,  either one will work fine if you remember that removing metal isn't the goal and can cause problems in some areas.  Reducing friction with the mating surface is the goal.

Don't mean to make a mountain out of a mole hill,  but several here can tell you about their problems when they removed too much metal or took away needed sharp flat edges---like in a sear et al.

[copemech]

I think a lot of this depends upon the part in question, but one needs to think about this process on a microscopic scale.

In many cases, if you looked closely the surfaces would look like mountains and craters. First thing is to knock the tops off the mountains, this may require 400 grit, at steel is hard! You will be there all day with less and not get the job done.

I want hills and valleys!, then take out any roughness with the finer paper. 1000 grit is real fine, guess one could go further, but I usually find nothing the Dremel and red rouge will not make shine like a mirror.

The flat tops of the hills and valleys just need to pass each other without dragging or catching on each other.

If there was such a thing as two perfectly flat surfaces passing each other, more drag could be induced via stiction.

But that is another story!

[BDG]

I think a lot of this depends upon the part in question, but one needs to think about this process on a microscopic scale.

In many cases, if you looked closely the surfaces would look like mountains and craters. First thing is to knock the tops off the mountains, this may require 400 grit, at steel is hard! You will be there all day with less and not get the job done.

I want hills and valleys!, then take out any roughness with the finer paper. 1000 grit is real fine, guess one could go further, but I usually find nothing the Dremel and red rouge will not make shine like a mirror.

The flat tops of the hills and valleys just need to pass each other without dragging or catching on each other.

If there was such a thing as two perfectly flat surfaces passing each other, more drag could be induced via stiction.

But that is another story!

Way off subject but... I sell a light source designed for adhesiveless bonding.   By cleaning organic and inorganic contaminants via a photochemical process we alter the very surface of an extremely flat, smooth material like Quartz Glass or Si, GaAs., i.e a Silicon wafers. The two clean surfaces can then be bonded simply by pressing them together. The bonding strength is strong enough for the material to be damaged during peel strength testing. Now that is flat and smooth!