Frosty glass surface

[Gaele Whitehouse]

Hi
I am new to the forum and I am seeking help to solve a problem I am having with kiln casting. On several occasions I have had a very frosty rough surface on the glass where it was in contact with the investment mould. Looks and feels like sandpaper.
Not sure what is happening
Thanks Gaele

[Dick]

Depends on the glass, investment etc. R and R has great release properties and leaves a nice satin edge. Obviously with investments it will never be polished, but the right investment and glass makes a difference. Gaffer casting is excellent to use