Each glass family has a typical recipe range. Soda-lime runs roughly 70 to 74 percent silica, 12 to 16 percent soda ash and 8 to 12 percent limestone. Borosilicate replaces most of the soda with boric oxide and adds a small amount of alumina. Lead crystal substitutes lead oxide for part of the lime. The calculator multiplies your proportions against the target weight and reports each material in kilograms.
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Enter a batch weight and set the proportions, then calculate.
About this calculator
A batch is the dry mix of raw materials that melts into glass. Get the proportions right and the melt is clear and workable; get them wrong and you spend a week chasing seeds and cords. This calculator converts a target batch weight and a recipe ratio into the actual kilograms of each material.
Choose a glass type, enter the total batch weight in kilograms, then set the proportion of silica sand, soda ash, limestone and any additional material. The output panel updates as you type.
Things to keep in mind
- Recipes in this range are reference proportions for education. Real production batches are adjusted for the exact sand and soda grades on hand.
- Melting temperature rises as silica content rises and falls as soda and lead oxide rise.
- A refining agent such as sodium sulphate or antimony oxide is usually added at well under one percent to help bubbles rise out of the melt.
- Weigh materials accurately. A two percent error in soda ash shifts the expansion enough to matter.
Reference only. Results are based on published ranges for common glass families and are intended for learning. Always verify against your own materials and equipment, and follow the manufacturer's instructions.