सुहागा (Borax (sodium tetraborate decahydrate))

Borax is sodium tetraborate decahydrate, a white crystalline salt of boron. Indian households and jewellers know it as suhaga (सुहागा). Goldsmiths have used it as a flux for generations. Today it's also bought for laundry, slime making and craft work.

• Formula: Na2B4O7·10H2O
• CAS number: 1303-96-4
• Molar mass: about 381.4 g/mol
• Appearance: white powder or colourless crystals, no smell
• Melting point: about 75 °C, where it starts losing its water of crystallisation
• Solubility: moderately soluble in cold water and much more in hot water. The solution is mildly alkaline.

Heated strongly, borax puffs up and then melts into a clear glassy bead. That glassy melt is what makes it useful as a flux.

Azlok's borax listings are general-purpose technical grade powder. None is sold as lab, pharma or food grade. You'll find a 200 g pack and a 400 g pack of borax powder, plus a household listing whose name doesn't give a pack size, so check the product page for its weight.

Check today's price per kg to compare packs.

• Household: a laundry booster that softens hard water and helps detergent work, and a scouring aid for tough stains on tiles and sinks.
• Craft and kids' projects: the classic slime activator. Borax cross-links PVA glue into a stretchy gel.
• Jewellery and metalwork: suhaga is the traditional flux for soldering gold and silver. It's also used in brazing and blacksmith welding.
• Industry: glass, glazes and enamels, fibreglass, and fire-retardant treatments for wood, paper and cotton.
• Lab: a primary standard for acid titrations and a buffer ingredient, though analytical work needs a lab grade.

Slime activator: dissolve 1 level teaspoon (about 5 g) of borax in 1 cup (about 250 mL) of warm water. Separately mix half a cup of PVA white glue with half a cup of water. Add the borax solution to the glue a tablespoon at a time, stirring, until it pulls away from the bowl. An adult should make the activator. Children should wash their hands after playing and must not put slime in their mouths.

Laundry booster: borax laundry booster packs commonly suggest about half a cup (roughly 100 g) for a full machine load. Dissolve it in warm water first so it doesn't leave white specks. Use less for a half load or a bucket wash.

Soldering flux (suhaga): mix borax with a few drops of water into a thin paste. Apply it to the clean joint, then heat. It bubbles, then turns glassy and keeps air off the metal while the solder flows. Clean the glassy residue afterwards in hot water.

Dissolving tip: borax dissolves slowly in cold water. Use warm water and stir for a minute or two.

• Borax is not for eating, and it must not go into food, drinks or homemade remedies. It's classified in the EU as a reproductive toxicant. Pregnant women should avoid handling it, and it should never be used around infants.
• Wear gloves for long handling and avoid breathing the dust. Wash your hands after use.
• Keep it out of eyes. If it gets in, rinse with clean water for several minutes.
• Keep it away from strong acids and strong reducing agents.
• Store it in a sealed, labelled container in a dry place. Borax picks up moisture and cakes.
• Keep it away from children and pets, and never store it in food jars or near the kitchen masala shelf.
• Small household amounts dissolved in plenty of water can go down the drain. Don't dump larger quantities into gardens, ponds or soil, because boron harms plants in excess.

For slime, a few laundry loads or occasional soldering, the 200 g pack lasts a long time. If you use borax every week for laundry or run a small jewellery workshop, the 400 g pack saves you reordering.

Technical grade is right for all the household and workshop uses above. It isn't for food, cosmetics or analytical lab work. Pottery units, glass makers and traders who need 25 kg or more can send details through our bulk inquiry page. Mention the form you need (powder or granules) and your monthly quantity.