The Making of the Glencairn Methuselah Window: Page 10

Modelling Clay Backing

26 grammes pontied <sp?> Burnt i.e. heated to redness Modelling Clay
40 pulverized white sand
48 Cullet 1 sand 4 red ground very finely
160 Red Lead
10 Carbonate of potash
4 Potassium Nitrate

Mixed and smashed material together on glass slap 1½ hours mostly with a piece of glass. It would not hurt to mix the material with an iron knife as that would make the tone warmer

The above amount fills Coors Porcelain crucible No5
I put a wire over the crucible and put the lid on

<fig 5 in three vertical sections
- drawing of crucible, at bottom of page, side view of kiln with door ajar, “hole open in door” and text below kiln “wires on to let air in”
- vertical view of kiln interior crucible with wire extending to door, bottom
of image labeled “EMPTY”
- text by crucible in kiln interior “cast iron plate on bottom of furnace”
text by bottom image, lower right corner “FRONT EMPTY CRUCIBLE”>