tool marks begone

[<moonsong@xxxxxxxxxxxxxx>]

Hi Tomas,

I'm glad you had success with this technique. I recently
helped a mate prepare a granite boulder plinth for a
granite statue- the plinth was 3.6m tall, 1m wide and
0.8m deep (about 9 tonnes mass, Australian Grandee
granite). My sculptor mate was not happy with the
weathered surface that was stained by sulphides,
scratched by lifting chains and excavating equipment, so
we decided to flame the surface.

I used a 150mm wide sparging tip (with a long handle)
burning oxy-acetylene and it removed the scratches and
brown flakes from the surface. It also found some hidden
weaknesses in major surface flakes, forcing them to
spall off- better than falling off after the
installation on an unsuspecting member of the public. I
removed a wheelbarrow load of spalls in a day's work.

I wore full overalls, boots and a hard hat with a full-
face visor, and found that this was sufficient
protection. I also found that the best angle for the tip
was about 15 degrees to the surface so the spalls don't
fly back in your face.

However, after the exfoliation of the plinth, we decided
to bush-hammer the surface to refine it a bit more-
didn't take as long as we thought, and made it look
great.

We used Superior brand air bottles with either Koenig-
Schmeider or Bavaria Stone Tools bush hammer bits. These
bush hammers are the type that fit into the end of the
air bottle and are about 75mm long. They are better for
granite than the type that are about 230mm long. They
really power into the hardest granite.

I was interested to read about your sandblast treatment-
I'll give this a go and report back soon.

Regards,
Simon