View Single Post
  #13  
Old 07-07-2015, 03:09 PM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 7,112
Alumina is good.. 5.4.
However it is very expensive.

Fused sillica is excellent (0.55). It is used for high end telescope mirrors..
Reply With Quote