We mix glass batch for the studio glass artist. All batch is agglomerated for easier, safer storage and use. All materials are selected and tested for use by studio glass artists, not large factories. Our batch is prepared by weighing and mixing the materials which compose the formula of the glass, then processing to form larger granules from finer materials. The process is commonly called pelletizing although pellets are not necessarily formed. The primary purpose of agglomeration is the prevention of segregation of materials (unmixing) during shipping and storage. However it has the additional effect of increasing safety by reducing the dustiness of the materials and when compared with loose batch, research has shown that agglomeration results in fuel savings and reduces furnace wear.

Our "house" formula was designed by Dominic Labino specifically for use by studio glass artists. The Labino Formula is available in a variety of expansions and with or without decolorizer. The most popular version of the Labino Formula has a theoretical expansion of 87.3 x 10^-7, with a measured expansion of 96-97 when melted. The annealing point is 477 degrees C. (890 degree F) and the softening point is 662 C (1224 degrees F).

Batch in 50-pound bags. FOB Spruce Pine

Labino Formulas 83 plain, 87 plain, and 92 plain : $.35 per pound

83 W/er, 87 W/er, 92 W/er (with decolorizer): $ .40 per pound

83W/er/TS, 87W/er/TS, 92W/er/TS $.42 per pound (this is our best batch)

BEF:Bullseye® compatible formula $.42 per pound

 

Gaffer : $.44 per 50 lb  pound or for 12.5 lb $.55 per pound

 

Batch in 12.5-pound bags. FOB Spruce Pine

For this packaging option please add $.10/lb to the 50lb price.

Custom mixing of formulas is subject to availability of materials. Price is dependent on materials and quantity.

This schedule is based on experience gained from melting in 150-lb. pot furnace, which melts at a rate of about 25 Ibs every two hours. A larger furnace would melt at a faster rate.
Preparation
You must have an accurate means of determining the temperature. Preheat your furnace to 2250 degrees F (1232 degrees C). Maintain 2250-2400 degrees F (1232-1315 degrees C) through the melting stage. Melting and fining at too high a temperature will cause cords.
Charging the furnace
Charge 15 lb. into the empty furnace (any kind). When the batch surface is flat and glassy, charge 25 lb. This will take up to two hours. If you have any problems with the melt decrease the size of the charge and wait until the batch is completely gone before adding more. Check furnace temperature to be sure furnace has recovered temperature. Continue melting 25 lb. charges the same way until the furnace is full. Each cycle will take up to two hours.
With day tank and invested pot furnaces care should be taken to see that the furnace is very well preheated as all heat comes from the top, and the raw batch acts as an insulator and prevents heat from reaching the bottom of the furnace.
Stirring the batch is not necessary, but may accelerate the melt and improve glass quality. The stirring would be done about midway in each melting cycle.

After the last charge raise the furnace temperature to about 2400 degrees F (1315 degrees C). We believe that you should not get over 2450 degrees F. Hold at 2400-2450 for about 8 hours. To check your melt progress take small gathers and look at the bubbles. When the bubbles are all larger than pinheads, you can turn the temperature down to your working temperature to squeeze the bubbles out. This will also take about 8 hours. Each furnace will function slightly differently. One furnace will squeeze OK if you turn down to your working temperature, another may need to be turned down 50-100 degrees below working temperature.

Working and Holding
A 2100-degree F (1184 degrees C) working temperature is a good place to start. You may prefer to work the glass either hotter or colder. Hold at working temperature as cords seem to develop when the glass is held at lower temperatures.

Recharging
Use all of the glass in the furnace and repeat the process.
Cords will build up in the bottom of the furnace, so it is recommended that you clean the furnace out at about weekly intervals, or at the longest every two weeks.

VERY IMPORTANT
If the temperature of your furnace is 100 degrees F too low it will take twice as long to melt and/or fine out. Most temperature readings are really measurements of the furnace atmosphere and not the glass temperature itself. Your furnace is in a constant state of change. Usually it is gradually becoming less efficient and otherwise gradually deteriorating. Furnace function and melt progression is also affected by various weather factors as is the batch itself when it is made. Insufficient time and/or temperature is the most common cause cause of poor melts