From: "Vero and Lisa Joseph" 
To: 
Reply-To: "Vero and Lisa Joseph" 


G'Day All
After two years off and on (_far_ more off than on!) I have finished fine
grinding my 300mm dia 30mm thick plate glass blank to a FL of 1900mm
(f6.3). The grinding was carried out on a full size 80mm thick concrete and
tile tool. This is my first tile tool after completing previous mirrors on
a glass tool. With these I have used the glass tool as the foundation for
my pitch lap. This time however I would like to preserve the tiled surface
as I do not relish romoving pitch from such a surface in case I have to go
back to grinding. I was going to build a lap base out of plywood when the
thought occurred to me touse the base of my tile tool (ie upside down) to
pour the pitch onto.

My question is - does the surface of the lap base need to have a convex
curve or will the flat bottom of my tile tool suffice? Thank you in advance
for any replies.

Vero Joseph
Goulburn, NSW, Australia (currently under strict water restrictions as
99.6% of the state is affected by the worst drought on record)

--- BBBS/NT v4.00 MP