Borax powder, sodium tetraborate

Please note: we only supply this product to businesses. Orders can be placed only with valid company details. Contact us with a Chamber of Commerce number and VAT number, and we will verify your details before we process the order.

Borax is a sodium salt that you use as a flux for forge welding. When forging Damascus steel, it binds the impurities on the steel surface so the layers bond properly to each other. The powder is white, is made from boric acid and is also known as sodium borate, sodium tetraborate or disodium tetraborate. We supply the anhydrous variant, sodium tetraborate, with the lowest water content of the three common types.

Use and application

In the forge, you mainly use borax for forge welding and for Damascus steel. It provides a low surface tension and therefore works well as a flux when soldering.

Outside the workshop, you can use borax directly or process it as an ingredient. As a standalone product it is used, among other things, as a drying agent, water softener, laundry booster, rust remover, cleaner for air conditioners and clogged drains, and as a household cleaner. As a pesticide against cockroaches and woodworm, it is intended solely for professional pest controllers; do not use it for that purpose yourself.

As an ingredient, you will come across borax in flux for welding iron and steel. It is also found in earthenware, ceramics and glass, in some toothpastes and tooth whiteners, and in flame retardants.

Types of borax

Borax is a collective name for related compounds that differ from one another in water content. There are three common types.

• Borax decahydrate: the highest water content, formula Na2B4O7 · 10H2O
• Borax pentahydrate: half the water content, formula Na2B4O7 · 5H2O
• Anhydrous borax or sodium tetraborate: water content zero, formula Na2B4O7

The mineral is written chemically as Na2B4O5(OH)4 · 8 H2O, or in the form Na2B4O7 · 10 H2O.

Safety

The most common form, sodium tetraborate decahydrate, is not acutely toxic. Small quantities generally cause no health effects. With large quantities the situation is different: inhaling it can irritate the airways, most quickly in children, and swallowing it can cause nausea, diarrhoea or vomiting.

Unlike many other salts, borax does not cause skin irritation. The European Union does consider the substance a potential health risk, as do Canada and Indonesia. This is because people are regularly exposed to it through food and the environment, which means total exposure can add up. Children and pregnant women are advised to limit or avoid exposure.

If you are unsure about an application, consult a professional before using the powder.

Legal designations

• Hazard statement (H code): H360FD, may damage fertility and may damage the unborn child
• Precautionary codes (P codes): P201, P308 + P313
• Instruction: obtain special instructions before use; if exposed or concerned, get medical advice

Specifications

• Type: anhydrous borax, sodium tetraborate
• Formula: Na2B4O7
• Colour: white
• Packaging: 800 grams and 4 kilograms
• Sales: business customers only, after verification of Chamber of Commerce and VAT number