Monday, June 11, 2012

Test Tubes

Set Up:
-         14 mm Pyrex tubing
-         # 3 tip
-         Matches/mats/towel/glass cutter
-         Blow tube
        -         Flaring tool or end of a file

Blowing Tube:  The end of a corn cob pipe to use as a mouth piece.  Small diameter surgical tubing to fit over the mouth piece and a swivel at the other end.  Another piece of surgical tubing, small piece of fire polished 6" glass tubing and an adapter for fit snugly over 14 mm tubing.  Ck out ABR Imagery for a set up.

Lighting the torch:
    Use the "POOP" method (propane on, oxygen on, oxygen off, propane off).
     Have your flame (match or striker) ready and hold it near the torch tip.  Turn on the red knob (propane), and obtain about a 6" orange flame.  Turn on the green knob (oxygen), and obtain about a 3/4" blue flame.
     Turning off the oxygen first (green), then the propane (red).  DO NOT OVER-TIGHTEN THE KNOBS!!!!!  YOU'LL RUIN THE NEEDLE VALVES AND YOUR TORCH WON'T PROPERLY TURN OFF!!!!!!!!!
      Do you work at the tip of the darker blue flame.

Test tubes w/flare (14 mm tubing):
  Remember:  Hot glass looks the same as cold glass!!  Don't burn the top of your bench, put your hot glass on the ceramic mats. 
     DO ALL YOUR WORK OUTSIDE THE FLAME!!!!  Use the flame to soften your glass.  Keep your glass rotating in the flame, for even heating.

-         Heat middle of tubing, remove from heat, and pull two ends apart.
-         Remove as much of the glass to prevent a large lens.
-         Heat the end and collapses the very end of the bulge
-         Remove the tube from the flame and blow out  to form a dome.  Remember:  DO NOT PUT YOUR TONGUE ON THE HOLE OF YOUR MOUTH PIECE!!  This prevents the air from circulating thought your piece and the hot, expanding gases will blow a hole in your piece.  This also goes for spit in your blow tube.  Chewing gum doesn't work either, can get stuck in your mouth piece...OH embarrassing!!
-         The glass should have a uniform thickness.  You may need to collapse and blow out the end a few times to get out any "wrinkles". 
o       Avoid lenses, causes stress points
-         Once cooled, lightly heat the edge of the tube, remove from heat, and form a flare w/the-flaring tool or the end of a file handle.

 Remember:  Turn off the green knob (oxygen) then turn off the red knob (propane).  DO NOT OVER-TIGHTEN THE KNOBS!!!!!

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