Have aquired some pen blanks in this material. Does anyone have any
experience in turning this and can offer advice. I realise it will
need very sharp tools, but am a little concerned about sanding and
polishing, so any help would be much appreciated.

John

john young wrote:
Have aquired some pen blanks in this material. Does anyone have any
experience in turning this and can offer advice. I realise it will
need very sharp tools, but am a little concerned about sanding and
polishing, so any help would be much appreciated.

John
You must jest. I don't think you can turn Mica with a normal tool.

You might get away with it by sanding.

You are talking stone and it is hard material and thin layers.

The basic material is AlSi3O10 with other KAL2(OH)2 tacked on.

So you are basically cutting an Aluminum oxide material.

They make sand paper with that material. Then another Aluminum oxide
within the matrix.

Carbide is the cutting tool. High speed steel will be cut or dulled
rapidly. Carbide uses pressure to cut and not a sharp edge - so it isn't
what is needed.

Use a Garnet sandpaper - Garnet will likely cut it. You might have to
get green paper boron...

Likely the method - spin it on the lathe and use a Dremel with a green wheel.

Martin

is this MICA substance a synthetic like corian? is MICA an acronym, or are
you referring to the mineral? As others pointed out, I doubt that the
mineral would be something you could do much with turning tools - kidna like
turning filo dough except that it's harder
"john young" wrote in message
...
Have aquired some pen blanks in this material. Does anyone have any
experience in turning this and can offer advice. I realise it will
need very sharp tools, but am a little concerned about sanding and
polishing, so any help would be much appreciated.

John

"Martin H. Eastburn" wrote in
:




Actually, when discussing hardness, in many cases the arrangement of the
atoms in the mineral's molecules is just as important, or maybe more so,
than the chemical composition of the mineral. A good example is the
difference in hardness between diamond, the hardest mineral, and graphite,
the softest. Both are pure carbon, just difference atomica arangements.

The Mohs hardness of mica is between 2.5 and 3, pretty soft, whereas
aluminum oxide sandpaper has a Mohs hardness of around 9, so sanding seems
to me to be entirely appropriate. However, how are you going to keep the
mica from flaking to bits? I assume you either have pieces of whole
crystals which cleave into extremely thin flakes (like in your old
toaster), or you have some kind of mica composite, with shiny mica flakes
in a binder of some kind, say, epoxy or polyester resin.

Seems like sanding is the way to go, as edged tools would catch on the mica
flake edges no matter what the composition.