Borax is a powdered form of boric acid crystals, which come from the element boron. Boric acid has many beneficial properties. It is used as an insecticide, antiseptic, flame retardant and mineral supplement. Rather than purchasing premade borax at a home supply store, you can make your own from boric acid crystals sold wherever chemistry supplies are sold. Use extreme caution when handling boric acid, as the exact effect on humans is unknown, according to the Environmental Protection Agency.
Purchase boric acid crystals at a home supply store or at a store that sells chemistry supplies. Purchase a small grinder that you can use to grind the boric acid. Do not use a grinder that you use for food, as boric acid can be toxic to ingest, according to the Environmental Protection Agency.
Place a small amount of the crystals into the grinder.
Grind the crystals into a fine powder.
Pour the powder into an airtight container. This will prevent the powder from clumping or causing injury to curious pets or children. Label the powder and store it in a safe place out of the reach of children and pets.
Always wear gloves when working with boric acid.
You can also make borax powder from the mineral sassolite, which is the naturally occurring form of borax in hot springs and other mineral-rich locations.