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Glass Blowing

IMG_5790Glass Blown Swan
By David Phukane
The Crucible

011 969 6105 or 072 998 9383

 

 

 

Requirements

  • Affrox hand torch
  • Table or Bench with a heat resistant top
  • Oxygen tank and regulator
  • Propane/LPG tank and regulator (only necessary if you do not have access to natural gas)
  • Hoses – generally red for LPG gas and blue for the oxygen supply
  • Stainless steel tweezers, 250 mm long and 150 mm long
  • Graphite paddle: 75 mm x 100 mm
  • Fire extinguisher
  • First Aid Kit
  • Didymium safety glasses
  • Glass tubes

 

Instructions

  • Step 1:
    • Put on protective eye wear.
    • Open the gas bottles, oxygen and LPG. Then open LPG on the burner/torch, just until you can hear the gas hissing out slightly.
    • Light the torch
    • Adjust the LPG flow, at the torch, to get the size flame that you require.
    • Open and adjust the oxygen at the torch until you achieve the optimum flame.
    • Position the yoke (the rollers on a stand) to carry the long end of the borosilicate tube.
    • Measure off approximately 120 mm’s, the length of tubing required to make a swan.
    • Heat the open end of the tube up by introducing it to the flame gradually at first and then rotating the tube in the flame, with the long side rolling on the yoke, until it is glowing red.
    • Using the tweezers pinch the end of the tube closed, remember to keep rotating the tube or you won’t get it to close in the centre.
    • Heat up more of the glass behind the pinched end and then pull a “point” out to about 200 mm’s long. This “point” will become your “holding” and “blowing” or working tube.
    • When the point has cooled introduce the glass tube to the flame at the measured distance of 120 mm’s. Heat the tube uniformly, always rotating it, until it is glowing red and then pull another point out to 200 mm’s. This is your working tube on the other end of your 120 mm length of 34 mm tube.Put the “Point” aside to cool.
  • Step 2:
    • Using a pre-made and cool “point” introduce the 34 mm section of the tube to the flame at about a third of its length from one “point”. Use the “working” tubes or points to hold the 34 mm section that you are going to make the swan out of.
    • When the section of tube is uniformly heated, to a glowing red, block of the one working tube with your finger and blow gently into the other working tube while pulling the two ends away from each other slowly. Blow and stretch until you have formed the swan’s body.
    • Now you are ready to work on the neck. Heat the of the body of the swan just behind the start of the “stretched point”, leaving enough thick glass attached to the “point” to form the head out of at a later stage.
    • When the glass is glowing red stretch it out as you would with a “point” but this time bend it back over the body and then back away from the body (in an “s” shape) quickly before it cools.
  • Step 3:
    • Now heat up the head until glowing red and blocking the head side working tube with your finger blow into the tail end working tube gently while pulling on the head side tube to blow the head out and “pull” the beak to a point from the head.
    • Now melt through the end of the beak and remove the “point”.
    • Reduce the oxygen flow slightly at the torch to cool the flame a little (more yellow in colour) and heat the entire swan slightly. It must not glow red the heating is to “equalise” the heat all over the swan and thereby remove thermal stresses.
  • Step 4:
    • Put aside to cool.
    • Turn the oxygen up a little again to heat the flame.
    • Using an already cooled swan heat up the remaining tail end point at the end of the swan’s tail.
    • Melt the glass through to close the tail and remove the point.
    • Put the completed swan aside to cool.

 

Glass Test Tube Flower Vase

 

IMG_5823Glass Test Tube Flower Vase

By David Phukane

The Crucible

011 969 6105 or 072 998 9383

 

 

Requirements

  • An Affrox hand torch
  • Carbide blade
  • A table or Bench with a heat resistant top
  • Oxygen tank and regulator
  • Propane/LPG tank and regulator (only necessary if you do not have access to natural gas)
  • Hoses generally red for LPG gas and blue for the oxygen supply
  • Stainless steel tweezers, 250 mm long and 150 mm long
  • A graphite paddle: 75 mm x 100 mm
  • Fire extinguisher
  • First Aid Kit
  • Didymium safety glasses
  • Glass rods

Instructions

  • Step 1:
    • Cut/score the glass tube at the required length of the test tube with a carbide blade.
    • Break the length of tube off at the score mark. Repeat for the number of test tubes that you wish to make.
    • Put on protective eye wear.
  • Step 2:
    • Open the gas bottles, oxygen and LPG.
    • Open just the LPG on the burner/torch, just until you can hear the gas hissing out slightly.
    • Light the torch.
    • Adjust the LPG flow at the torch to get the size flame that you require.
    • Open and adjust the oxygen at the torch until you achieve the optimum flame.
    • Introduce one end of the tube of glass that you cut earlier into the flame gradually. Wave it in and out of the flame a few times before holding it still in the flame.
  • Step 3:
    • Rotate the end of the glass tube in the flame until it begins to glow a uniform red around the rim of the tube.
    • Pinch the hot rim with tweezers and “pull” the excess hot glass of the now closed tube until you are left with a uniform amount of glass (wall thickness) throughout the hot (molten) area. “Pinch” the excess off the end thereby removingit. Do not let the tweezers get too hot or they will stick to the glass, dip them in a tin of cold water if necessary.
  • Step 4:
    • Put the still cold and open end of the tube to your lips and blow gently until the hot end blows out to form a rounded bottom.
    • Put the tube to one side (on a heat resistant surface that isn’t too cold or the tube might crack) to cool down.
  • Step 5:
    • Pick up a cold tube that already has the bottom closed and blown round.
    • Introduce the open end into the flame gradually and heat uniformly until glowing red.
    • Flare the open, hot end of the test tube by “pushing” it open with the tweezers while rotating the tube.
    • Put your finished test tube down and allow it to cool, when it is cool place it the vase holder and add your flowers.