Just woke up ....
After an all-night-through -RIU-blah-blah-session...
Got to go for some work ....
( !!! )
Anyway ...
Supra ,those Prolimatech thermal pastes, kick ass !
WoW!
( Although ,I think Ther. Cond. of pure/soft Alum is close to 230-234 W/m.K ..Anyway ..Trivial...)
What I wanted to say ...
I've discovered ,that if you sand the heatsink ,with the finest grit of sandpaper ..
(the finishing / final 'round' or 'session' ...)
Better to do it softly by hand ,(a sandpaper 'sponge ' -3M/ Bosch /etc- might help to keep sanding flat )
and under the water tap (in the sink ...) with some water running / being poured to the sanded heatsink surface ,
while sanding ....
The 'hydro-slide-water -film ' that is being created during the sanding motion ,really gives the final surface ,a roughness ,(most probably ) -much ?- lower than the finest sandpaper alone, (if used dry) would've given ...
Just something ,I 've discovered ...
(And none of aluminium dust,which is rather great ! )
Using this method ,I've sanded my heatsinks ....
To a level that almost feel the same like the back side of the CXA's
(^^^^Ok ...Now ,I might be exxagerating ....But really 'feels' (and 'looks ') way-way 'smooth' ,
like the ceramic surface of the CXAs ....'Like' .....)
...
Cheers,brother .
C'mon Digikey.... 
