Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[maestro]

   Five years of great cab work and no problems... then... boom! I got a definite "golf ball" surface on a snowflake obsidian cab.  I can't remember what causes this or how to fix the cab.

HELP!!!

[Orrum]

The white snowflake is ash. It undercuts sometimes badly or not depending on the silcification. Same reason knappers don't like snowflake, the flake hits the soft spot and either stops or changes direction and shoots straight up causing a hinge or step.

[Steve Ramsdell]

Sometimes it may be something as simple as letting the polish wheel dry out.  Did you feel a little tugging?  Or like me, maybe you get a little heavy handed in a rush.
Steve

[lithicbeads]

Snowflake obsidian  has feldspar phenocrysts  , not ash , in it. The feldspar is a different hardness than the body mass of the obsidian. Over sanding with fine grits can cause the type of undercutting you are referring to , the orange peel effect. It can be tricky to find the correct sanding sequence  but  this rock is quite soft so it is easy to oversand with the finer grits and cause orange peel. In the sic days a well worn 600 grit belt run quite dry would make short work of it in  the hands of a very experienced cutter who would not overheat the stone, there was a real art to it.

[vitzitziltecpatl]

Good info there Lithicbeads. Your comment on overheating obsidian took me right back to my early days. Still remember looking at a cab I didn't keep moving quickly enough and wondering where that spot came from. Some stones like heat, some don't.