Regarding the surface finish in aluminium, if aesthetics are important then I'd use a small step over (maybe 0.1mm) which should be adequate to then sand/polish it in a reasonable amount of time.

To get good thermal conductivity you do want it really smooth. I wouldn't polish it though as you could easily inadvertently leave dips which wont make contact over a relatively large area.

Quote Originally Posted by JAZZCNC View Post
Ah ah you shit stirring little Geek I wasn't calling anyone a Muppet or having a go at Rufe0 so bugger off and twiddle some wires. .
Bit of a struggle to twiddle the wires I'm using to be honest:

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