A.) Open main valve and evacuate unit to 0 mm (Torr). Close main valve.
B.) Backfill with 3mm (Torr) of air.
C.) Switch on bombarder and increase to 250mA. Hold at this setting while maintaining pressure between 3 and 4mm (Torr) with main valve.
D.) When the unit is at 120C/248F, increase current to 350mA. maintain pressure between 2 and 3mm (Torr) with main valve.
E.) Continue bombarding at 350mA until glass temperature reaches 150C/302F. Increase current to 450mA. Maintain pressure at 2 Torr.
F.) When glass reaches 200C/392F, reduce pressure to 1.5 Torr and maintain current at 450mA.
G.) When the electrodes are completely red and the glass has reached 230C/450F, open the main valve for a few seconds and then switch off the bombarder.
H.) With the main valve open, allow the tube to cool to around 50C/125F with a vacuum gauge reading less than 5 microns.
I.) Fill the unit with gas.