WORKING WITH GLASKOLBEN

The prefabricated cylinder saves the time consuming and tedious task of “pulling points” from a glass tube. Glaskolben is available in two forms: Sealed End Cylinder and Duel Spike Cylinder. The sealed end cylinder is available in either a 1.0mm or a 1.5mm wall thickness. The duel spike cylinder is available in 1.5mm wall thickness only. The wall thickness governs the maximum blown form size.

Glaskolben Glaskolben ornaments can be blown freehand or into a mold for three-dimensional shapes. Stock molds are available or the glass artist can fabricate custom molds.
   

EQUIPMENT

 

All that’s needed is a torch such as the Hot Head for MAPP gas, or a gas/oxygen torch such as the Nortel Minor, a set of tweezers and a scoring knife. A means of annealing is also required: vermiculite in a crock pot or a fiber blanket will work.

Mold clamps, molds and an annealing kiln are optional.

Equipment
   

SUPPLIES

Supplies
Glaskolben cylinders, frits, powders, stringers, noodles, or whatever or wish to decorate with as long as it is compatible. Glaskolben has a COE of 89, so any 90COE products will work.
   

GLASS BLOWING AN ORNAMENT

Blowing an ornament is easy, however, it takes time to get the feel of the glass as it softens in the flame. Be patient and have fun. No one creates a perfect piece all of the time.
   

TO START

001 Light the torch and adjust the flame back from a sharp point. A slightly broader flame is better. Select a sealed end cylinder and introduce it into the back of the flame. Rotate it as it is brought into the hotter part of the flame. Continue to rotate until the cylinder is glowing red and starts to reduce in size or collapse. However, DO NOT let the neck end of the cylinder get as red or the cylinder will be hard to manipulate.
   
002 Remove it from the flame, hold vertically, and give it a quick snap to align the cylinder. Blow steadily into the blowpipe end to a full ball, whole rotating. This is where you must “get the feel of the glass” Overblowing can cause a blowout. The ball must be annealed at this point. See instructions below.
   

ELONGATED BLOWN SHAPE

004 To make an elongated shape, follow the same procedure as in blowing a ball. Rotate the cylinder in the flame until it starts to glow red in colour. Then use your tweezers to pull the end as far as desired while blowing and rotating. The ornament must be annealed at this point.
   

BLOWING INTO A MOLD

005 Pre-warm the mold in the flame. Prepare the cylinder in the flame as you did when blowing a ball. As the cylinder softens, place it into the pre-warmed mold. With the blowpipe in your mouth, blow hard to allow the soft glass to fill out against the mold walls. Open the mold, remove the shape and anneal.
   

ANNEALING

This is the process of toughening brittle glass by heating and slow cooling. Each manufacturers glass can have a different annealing range. In the case of Glaskolben, the annealing temperature is 950 F (510C). There are different methods of annealing:

1 – VERMICULITE
Place a blown shape deep in a container of vermiculite warmed on a hot plate or in a crock pot. Make sure that the red glow from the glass has faded so the vermiculate doesn’t stick to the glass.

2 – FLAME ANNEALING
Move the glass shape out of the hot area of the flame (blue colour) and into the yellow range for 2 to 5 minutes to allow to cool slowly and anneal.

3 – KILN ANNEALING
This is the most reliable method. The kiln control can be set for the desired annealing temperature, and run for twenty minutes or more. The amount of time over twenty minutes makes no difference. One cannot over anneal. Shut off kiln after twenty minutes and leave product in kiln to cool slowly.

   

REMOVING THE BLOWPIPE END

After the ornament has annealed, the blowpipe end can be removed. The best method is using a carbide scoring tool. With the tool in one hand and the ornament in the other: press the sharp side of the carbide steel against the blowpipe neck and press the thumb of the same hand against the other side. Rotate the shape while scoring the neck. Still holding the ornament, tap the blowpipe end to break it off.

008
An ornament cap can be placed on the ornament to finish it off. DON”T DISCARD the cut-off neck. It can be decorated to make a stylized bell, etc. 008
   

DECORATING THE BALL

Paint Surface As soon as you are comfortable with making a freehand ball, you may want to make a coloured ball.
   
Paint Surface

One method is the paint the surface with Vitrea 160 paints, designed specifically for glass Once painted, they are “fixed” by placing in an oven or kiln and firing to 325F.

 

 

Another method is to use coloured frits or powders. Fill to approximately 1/5 of the cylinder or just beyond the bend. Rotate the cylinder in the same manner as with the glass ball. It will take a little longer to bring the ball to blowing temperature because of the added volume of melting frit. The result is worth the added time.

A variation on the use of frit and powder is the method the production European blowers use. Place some frit or powder in a frit tray or on a graphite marving plate, and roll the hot cylinder over the frit, then reheat the frit on the cylinder in the flame. Blow into shape.

Stringers or Noodles produced by Uroboros or Bullseye (90COE), offer another form of surface decoration. Select one, and while rotating the HOT Glaskolben cylinder away from you, heat the tip of the stringer in the flame. Place it under the cylinder, attach it, and then allow it to trail around the cylinder. The stringer may be burned off at the finished end. The point of the stringer may also be applied to the ball at a 90-degree angle to create dots.