From:
Bill Brayman <meta@xxxxxxxxxxx>
Date:
Mon, 13 May 2002 22:43:49 -0700
Subject:
working with basalt columns
At 5:29 PM -0400 5/13/02, Calvin Babich wrote:
Quoted text begins.I am a sculptor working with basalt for the first time and would appreciate
any input on tools and techniques. I need to (unfortunately) remove the
patina entirely from one four foot column.
End of quote.
You know, of course, that basalt lovers cringe when they
hear about columnar crust being completely removed! As
george says, make sure you study Noguchi's stuff first.
A remarkable contemporary artist to also study is
Kazutaka Uchida. Of course, you probably have a specific
purpose in mind. But these two artists shed a whole new
light on mixing natural surface and artistic carving.
Sandblasting is probably the least efficient way to
remove the rind, as they call it. Not to mention that it
costs $500 minimum to rig up breathing and hood
apparatus, etc for sandblasting large pieces. And you
end up with a powder gray surface. And probably lung
disease.
But, anyway some ways to remove basalt rind:
1. Bush it off with carbide tiped bushing chisels. This
is an excellent way to do it. Especially when you
experiment with mixing bushing marks and polished
surface. And you can use a frosting chisel to leave a
finer surface. (bushing and frosting chisels have a flat
square face of about 9 or 12 chisel points)
2. Grind it off with a course diamond cup wheel ($80 or
more, but worth it)
3. Saw it off. This is tricky but you can jury rig
mechanisms to control the saw cuts to get it roughed out
with many parallel cuts. But you still have to smooth up
with a diamond cup or maybe good silicon carbide
sandpaper.
4. On edges you can pitch off large chunks that look
like flint knapping. Check out some flint knapping web
pages to see how you can efficiently knock off wide
shards.
You mostly have to use diamond and carbide tools. You
are working with something that is like hard glass
(silicon-based microscopic crystals). Good grade silicon
carbide sand paper works (usually the dark gray or black
sandpaper.) It's just that sandpaper works best at
smoothing, but not so good when hogging out lots of
material. Diamond sanding pads, however, have enough
cutting power so that they can be used instead of a
grinding cup. You have to use water and you don't get as
flat a surface (waterless pads are available, but they
aren't as efficient). In any case 30-60 grit is about
the most common grinding grit to start with.
One last thing about working with basalt. The fine
homogeneous grain results in fracture patterns that are
erratic. Sometimes it will seem like it's very hard to
break, other times just dropping on a grass lawn will
break it. Rough yard handling often shows up later as a
tiny fracture. Same is true with blast quarried basalt -
tiny microfractures. So, beware if you are working with
road cut rocks.
have fun,
Bill
- References
- message 00379: working with basalt columns - Calvin Babich (13 May 2002)
- Previous by Thread: message 00380: working with basalt columns - George Graham (14 May 2002)
- Next by Thread: message 00382: Books about lettering - JPillot (14 May 2002)
- Previous by Date: message 00380: working with basalt columns - George Graham (14 May 2002)
- Next by Date: message 00382: Books about lettering - JPillot (14 May 2002)
