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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.
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