View Single Post
  #58  
Old 03-10-2010, 08:36 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 20,404
Pete VanderLaan is on a distinguished road
Well, they handle them as well as any other good high alumina pot will handle them Slate. It isn't fluorine that is hard on a crucible, it's low viscosity.. When I melt opals at about six percent flurorine, I never let the furnace get hotter than 2200F which yield a viscosity similar to that of SP87 at about 2415F. When you look at issues like silver metal drilling a crucible, it's the fact that the metal is like water. There's nothing special about the silver. Think what would happen if you melted SP87 at 2550F. It attacks the porosity of the pots.

I forget who said it ( Fritz would now give me a huge lecture), but it is "think of glass as the universal solvent."

I know that Croucher gets about 25 melts from a fluorine alumina pot as opposed to about 40 melts for his lead transparents in AZS. The price difference is huge. And it's
always a crap shoot.
__________________
Where are we going and why am I in this basket?
Reply With Quote