Important - read the safety instructions for handling sodium hydroxide (also known as caustic soda, lye or NaOH) before mixing.
When measuring the ingredients into the jugs be sure to remember to tare or zero the scales. Taking accurate weight measurements is a safety issue and its importance cannot be overstated.
1. Weigh the water into the first jug.
2. Weigh the sodium hydroxide into the second jug and set aside.
3. Carefully pour the sodium hydroxide into the water (not the water to the sodium hydroxide) in a well ventilated area and stir gently until completely dissolved. Cover and set aside to cool (this may take several hours).