Cast Glass Paperweight Made
From Fusing Glass Cullet

It is first fused, cold worked fire polished and then annealed.

Glass cullet, which are pieces of broken glass, is used to minimize air bubbles that are usually present in frit casting.

To make cullet or frit - insert scrap glass between sheets of newspaper place on concrete, tap with a hammer until glass is reduced to the required size.

Always wear safety glasses as some glass may escape from the paper.

The glass produced is larger than coarse pieces of commercially bought frit.

Coarse frit can be used if it is easier.

The same technique is used to produce small pieces of frit or clear dichroic frit for adding to the mold. Suitable dichroic frit can be purchased if desired.

If using dichroic then transparent glass will be needed for the cast glass paperweight so that the dichroic can be seen. Opaque fusing glass can be used if dichroic is not needed.

This cast glass paperweight has been made with Bullseye glass.

The following items will be needed to make the cast glass paperweight.

Fusing glass cullet, transparent or opaque.

Dichroic frit.

Hemispheric fusing mold.

Kiln wash.

Prepared kiln shelf.

High temperature wire.

Diamond hand pad.

Glass grinder.

Glass fusing kiln.

Mold Preparation

Apply about five coats of kiln wash evenly to the mold.

Wait for each coat to dry before adding next coat.

Ensure air holes in mold are not blocked with wash, clean from inside with small pin. Do not remove wash from walls as glass may stick to mold.

All uneven surfaces inside mold must be smoothed or they will be transferred to the glass.

When mold is dry rub finger over uneven surfaces or use very fine sandpaper to produce a smooth surface. Remove all dust from mold.

Wrap a few turns of high temperature wire around mold. This is a safety precaution in the unlikely event of the mold cracking.

Fill mold with cullet, if using dichroic place it between layers of cullet to give a color depth to the piece.

Keep dichroic away from the edges of the mold as it can move through the mold during the fusing cycle.

Be careful when adding glass that the kiln wash is not scratched. Damage to the kiln wash may result in the glass sticking to the mold.

Once mold is filled, pile glass up in the center of the mold as per photo. The glass will settle down into the mold as it fuses, this will be the bottom of the paperweight.

Sit mold on prepared kiln shelf and place in glass kiln.

As this is cullet, the fusing temperature can be taken up rapidly to full fuse. However, take it up at around 500° F (260° C) to about 1500° F (816° C).

Hold for fifteen minutes, or until the top of the glass is smooth and flat. This is the bottom surface of the paper weight.

Turn off glass kiln, do not vent kiln or open door until the kiln has cooled to room temperature. Opening the kiln may result in the glass cracking.

Cold Working

Remove mold from kiln and set aside for twenty four hours to allow glass to cool completely before taking from mold.

The glass may have developed small sharp needles around the top edge, which will need to be ground away with a tabletop glass grinder.

If kiln wash has stuck to the glass, use a fine wet diamond hand pad to remove it.

Clean glass thoroughly. Once clean handle with soft cloth or gloves to prevent finger marks being left on glass.

Fire Polishing

In this segment the glass will be fire polished and then annealed to remove stresses from the paper weight.

Place glass on a prepared kiln shelf and put in glass fusing kiln.

Due to the size of the glass which is 2 7/8 inches across x 1 1/8 inch thick the glass must be heated slowly to prevent thermal shock occurring.

Raise temperature by 200° F (96° C) per hour to 1100° F (593° C), hold ten minutes, continue at 200° F to around 1350° F (732° C), hold for a further ten minutes.

The glass should be nicely polished with rounded corners.

Do not over fire as the glass will begin to flatten out.

Drop temperature AFAP to 900° F (482° C).

Hold at this temperature for four hours to allow annealing to be completed.

Do not open kiln door until cooling is completed.

Allow kiln to cool to room temperature before removing glass.