Name: Loraine

Message: Hi there
Love your site, it has been so helpful. I am just starting out withe Batik. I purchased some dye from my instructor (in Asia). Apparently, to set this dye I need sodium silicate. It seems as though most suppliers of dye here don't require sodium silicate so it's super hard for me to find. If you know of anyone that supplies it OR if you know of another chemical that could replace it, that would be super helpful for me. Thanks a bunch in advance.

Do you know exactly what type of dye you are using? Knowing this might be useful in selecting the best substitute for your sodium silicate. [See "Sodium silicate as a fixative for dyeing", added to this site in March of 2010.]

Sodium silicate solution is used to produce a high pH in order to set fiber reactive dye on cotton or silk. It is often used as an after-fix, by painting the dye onto the fabric, letting it dry, then painting on the sodium silicate, leaving the silicate to react with the dyed fabric for an hour, then washing it out. It is very important not to let the sodium silicate dry on the fabric.

Sodium silicate solution is sold in the US by PRO Chemical & Dye (under the names 'PRO Fix LHF' and 'PRO QuickFix') and by Dharma Trading Company (under the name AfterFix), in Australia by Batik Oetoro (under the name Drimafix), and in Spain by Tobasign Dyes (under the name Tobafix). I don't know of specific sources in Asia, though I do know that it is available there for industrial use. Other names for sodium silicate include Water Glass, Soluble Glass, Silicate of Soda, and Egg Preserver, according to J.T. Baker's materials safety data sheet.

Since the purpose of the sodium silicate is to raise the pH to approximately 11, there are several good substitutes for it. 

The most commonly-used pH-increasing chemical is soda ash, also known as sodium carbonate; it is found in washing soda, as well. An advantage of sodium carbonate (or soda ash or washing soda) is that using a little too much or too little will not change the pH much. Sodium carbonate is a relatively weak base, so it tends to produce a similar pH even if you use more than you need to. It is usually used by presoaking the fabric. For batik, you can apply the wax to the fabric and let it cool, then soak it in soda ash (mix one-half to one cup per gallon, or 36 grams per liter); squeeze out the excess liquid so that the fabric is damp but not dripping, then apply your dye. Keep the dye moist on the fabric overnight in a warm place. The required temperature for the dye reaction depends on the specific dye you use. It is safe to let soda ash dry on cotton, unlike sodium silicate. for more information see "What is soda ash, and what's it for in dyeing?".

Another good substitute for sodium silicate would be trisodium phosphate (TSP). This is a powder that produces solutions that are more basic than those produced by sodium carbonate, so it results in a somewhat higher pH. This means that it is a little more caustic and irritating to the skin, and less suitable for use with children, but it is easy to use safely if you are careful. I like to use TSP with Remazol dyes (vinyl sulfone dyes); they will set on cotton or silk with soda ash, but I have the impression that the higher pH of TSP works better for me. TSP is mixed with water for use as a cleaner, especially for washing outdoor walls before house painting; I find mine in the paint department of the local hardware store.

A third pH-increasing chemical which is widely used in the textile industry is sodium hydroxide, also known as caustic soda or lye. You can purchase it in the form of granules or crystals intended to use in unblocking drains which are clogged with grease or hair. I do not recommend the use of sodium hydroxide for people who are not trained in laboratory chemistry, because the pH it produces is much higher, so there is more risk of burns to the skin or eyes. If you do use sodium hydroxide, please learn and follow safety precautions: wear sturdy gloves, a plastic apron, and a plastic face shield, or at least safety goggles, and always add the sodium hydroxide to water, never water to the sodium hydroxide, because it may spatter. Use plastic or glass utensils, because lye may react with metals such as aluminum. It is more important to use exactly the right amount of the chemical when you are using sodium hydroxide, because it will produce a pH that is much too high for an optimal dye reaction, if you use too much. Only a small amount of sodium hydroxide is required, as compared to soda ash or TSP, for the same rise in pH. You must weigh your sodium hydroxide crystals and a reliable small scale. Use pH paper to test whether the amount of sodium hydroxide you are using produces the desired pH when added to the same total volume as you are using in your dyebath.

Let me know if you have any clues as to what exact dye you are using.

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