How To Make LyeMake Lye At Home: Can It Be Done? Lye, also known as caustic soda or sodium hydroxide, is an important chemical in many processes including home based soap making and biodiesel production. Is it possible to produce lye for ourselves and so reduce the overall cost of home based productions? Using Salts To Produce Lye 
Recipes to make lye at home vary but generally involve Sodium Carbonate (also known as washing soda) and Calcium Oxide (CaO) which is converted into Calcium Hydroxide, Ca(OH)2 when water is added. It is important to note that both these chemicals need to be purchased as making these reactants will further increase the chain of costs associated with home lye production.If those two basic ingredients can be purchased at a sufficiently lower cost than the purchase cost of lye, it may be worth your while to give it a try. Using Electricity To Make Lye Industrial production of Lye is performed through the electrolysis of brine in what is called a Membrane Cell. This means a concentrated solution of salt water (NaCl) is provided with an electric current. The energy provided to the salty water is absorbed by the atoms in the solution forming new chemical bonds that contain that energy.
The -OH produced here is called hydroxide and it is the active part in Lye. Note that the hydroxide produced is mixed with the salty water and needs to be separated before use; this alone is a difficult and expensive process. All the chemicals formed from this process are unstable as they have more energy than their surroundings. This makes them prone to taking part in chemical reactions in order to form more stable products and release the stored energy, usually as heat. The concentration of the brine will affect the production of gas at the electrodes. If it is very dilute, the products will be hydrogen and oxygen gases which also has the effect of using up the hydroxide ions. The reactions for this are shown below:
This gives the overall reaction: 2H2O ==> O2 (g) + 2H2 (g) This is fine if you are trying to produce Hydrogen gas for fuel use, but is of no value for lye production. Note here that while hydroxide (the OH-) is still produced, it reacts with the free H+ ions (protons) and reforms water molecules. For this reason the electrolysis of either pure water or slightly salty water is of no value for producing hydroxide and therefore Lye. Safety Considerations
Safety must also be a major consideration if you are considering attempting to make lye. Gases given off from the electrodes are either highly toxic in the case of the Chlorine or likely to explode in the case of the hydrogen. Needless to say the consequences of the buildup of flammable gases in a suburban residence could be extreme. These two gases could also mix together to produce hydrochloric acid vapour which could also cause severe health problems.Cost Effectiveness Another important consideration is the amount and cost of the electricity needed for the electrolysis and the equipment to perform it. It is unlikely that any savings can be gained through home manufacturing of sodium hydroxide, even if all the safety aspects were covered. Given the ready availability of bulk supplies of this product at quite low prices, any attempt to make lye at home would surely have to be in the realm of just-for-the-hell-of-it experimentation.
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