Weighing out the silica gel.
Weighing out the Sodium Hydroxide (lye)
The silica gel dissolving in the Sodium Hydroxide and water.
The final product. (2 runs worth) Stored in an old pickle jar.
Water glass is the common name for a group of compounds called Sodium Silicates, Na2Si03 It's made from water, Sodium Hydroxide (common lye) and silica dioxide (white sand) and the ratios of sodium to silica determine which compound is made. I'm using silica gel (which is a porous form of silica dioxide) instead of silica sand because it dissolves easier. A cheap source can be found in the form of crystal cat litter. Water glass has many uses, however I required it for refractory cement to line a furnace.
The materials I used:
sodium hydroxide
silica gel
water
weight scale
stainless steel or teflon coated pot
metal spoon
measuring cup
I used a ratio of 3:2 silica to sodium hydroxide for my mixture a 2:1 will also work. A ratio of 4:3 is commonly sold as waterglass for sealing concrete or waterglassing eggs and other uses. I started with double the amount of water in milliliters as the weight in grams of silica used and added more to get the viscosity I needed. The higher silica ratio I used required extra heating and stirring to get everything to fully dissovle.