Surface Roughness of #8 mirror finish

[Auspex]

Hello,
I purchased a sheet of aluminum from McMaster Carr with a #8 mirror finish. I can not seem to find an information that relates this surface roughness. Anyone know?
thanks.

 

[vanstoja]

Possibly the #8 mirror finish means a surface rougness of 8 microinches, root mean square (rms). Surface roughnesses in microinches usually run in the sequence 4,8,16,32,64,128,256...,etc. The 8 microinch finish is quite smooth and could be qualitatively called a "mirror" finish.

 

[IRstuff]

Don't think that's the rule. The #4 finish is "satin" brushed, so the sequence goes the wrong direction.

Also, M&C have a finish called "reflective"

You should probably call or email them

TTFN

 

[Auspex]

Believe it or not, they didn't have that info.

 

[IRstuff]

Yeah, got the same lame answer. pretty pathetic.

Have you gotten the material yet?

TTFN

 

[Auspex]

Yea, got it late last week. It has a really nice mirrored finish. You could shave in it. I suspect it is in the low single digit microinch range or better....but I haven't held a lot of very flat/smooth materials in my hands either so I am just speculating.

 

[IRstuff]

That seems to be the rough ;-) consensus:

http://www.plasticstechnology.com/articles/200403fa3.html

http://www.outokumpu.com/pages/Page____5882.aspx

http://www.assda.asn.au/asp/index.asp?pgid=17975

http://www.delstar.com/services/quality/mill.html

Since it does appear to be some sort of industry standard terminology, it's even more pathetic that M&C can't or won't give out the information.

TTFN

 

[Auspex]

Great, thank you for the help! One other note of interest if anyone is considering ordering on of these plates. While the surface is really nice, the flatness at the outer edges is horrible due to the cleaving of the plate into a square. Also, McMaster sent the plate in a box with no padding or packing outside of a sticker to protect the finish. It is riddled with dents & dings...