Sealing Glass Ampules or Samples under Vacuum
By Joe Walas, East Carolina University
Department of Chemistry Glassblowing Facility

The Ampule or Sample Tube

Go to the opposite side of the glass that was heated in step two and repeat the process. Do not try to complete the seal off yet.

Heat the rear portion of the constriction and allow the wall to collapse.

Heat the front portion of the constriction allowing the glass to collapse and complete the seal. Keep the torch flame on the glass and go to the next step.

Keeping the glass hot, pull down on the sample bulb. This step will further reduce the diameter of the constriction (which should be solid glass at this point). You can now tip off (melt away) the sample bulb from the main tube.

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