Glazier's benches are used to make glass products. Potash, lime and sand are needed to make melted glass, and white sand is needed to make jeweled glass. Different glass products can be made by shaping glass while the temperature is maintained at 1600 - 2400 degrees by adding charcoal. Each glazier's bench works differently than other benches so one method that works well on one bench may not work well on another bench.
See the treatise on glass making for specific information on producing different glass products.