/diy/ - Do It Yourself

>>794467
There is usually a small percentage of "filler" in the lye container. Usually, it's other chemicals that are part of the manufacturing process or for aid in storage. On places like Essential Depot or Brambleberry, the lye you get is usually 97-99% pure. Mostly, the extra chemicals are sodium bicarbonate, which is harmless.

But the way it works, you pre-measure your water (use distilled and nothing else), add your lye to it and stir. When your lye water becomes mostly see through and has cooled to within 10 degrees F of your oil temps, you can mix them. Your oils are basically chains of fatty acids. Things like olive oil, coconut oil, lard, tallow, etc.

As your mixture undergoes saponification and hardens, the sodium bicarbonate tends to float to the surface, leaving a film or "scum" as you put it. This is known as Soda Ash. You can remove it pretty easily, but best to prevent it by spraying your molds and the top of your hardening soap with rubbing alcohol.