09 - Glass sphere
All glass may be formed in a kiln to some extent, where as glass that is fused to each other, as in the coloured strips shown in this sphere, is best achieved with some guarantee of manufacturer compatibility.
Where a precise form is desirable a mould must be made of material capable of remaining stable at the temperature necessary for the glass process; in this case a 50:50 mix of plaster and flint.
Several hemispheres were formed, see slides, then cut, ground and joined using UV reactive cement. Holes may be cut using diamond tipped drill bits, at a very slow speed while lubricated with water. see video.