How to Make Lye

For many people, Fight Club was their first introduction to lye.  Beyond those people many more people still are unaware of the variety of uses that lye has, and how useful it is in the PAW.  It is used to produce soap and bio-diesel, it is used to cure food and can be used as a heavy-duty cleaner.  It is one of those things that is vital to your post-apocalyptic needs.  Lye is an alkali that can be retrieved from the ashes of hardwood (such as ash, beech, birch, oak, etc.), so making lye is as simple as drawing it out of some ashes.

At this point it should be noted that lye is extremely caustic and can cause painful and lasting damage should you get any on your skin.  If you are exposed to a chemical burn from lye, immediately rinse the exposed area under water for 15 minutes (don’t listen to Tyler Durden, that guy isn’t real and he wants to blow things up) and then tend to the wound normally to prevent infection.

  1. First, you need to have a vessel in which to store your ashes.  A barrel is a good choice, but you can use anything.
  2. Drill a hole near the bottom of the barrel and fit it with some kind of cork.
  3. Next, you need to build a basic filtration system at the bottom of the barrel, start out with  small rocks and then cover those with a thick layer of grass.  This will filter the ash and let your final product run clear.
  4. Fill your barrel with ash from hardwood.  You can simply keep all the ash from any camp fires or cooking fires you have and periodically add it into the barrel (provided they are wood fires).
  5. Once you have enough ash in the barrel (your preference), you need to add water (the softeer the better) to your barrel to let the ash soak.  Uncork the drain hole, pour water into the barrel until it starts to come out of the drain hole, then plug the drain hole again.
  6. Let the ash soak for around three days (or until a potato floats enough that a 1-inch diameter circle is above the water) and then drain the barrel into the containers you wish to store your lye in.

If you want to run a continual system, just continue to add ash and drain off the lye and add water about once a week.

This process will give you lye that is properly strong enough to make soap.  If you need a stronger solution of lye, you can boil it down.  If you need a weaker solution, add a bit of water.

Author’s Note – For as long as I’ve known how to do this, I’ve known about the potato trick (this is actually how American colonists determined the strength of lye) but I’ve never known why that determined the lye strength.  Can anyone explain why?  +100 Internet points to the person that does!

7 Replies to “How to Make Lye”

  1. Hey man I think I put an edge on rock by smacking the sides of the rock taking flakes off of the side. Though it wasn’t sharp. Does that sound like the right way to do the method?

      1. It might have been sharper if I had tried to use flaking tool on the edges that I made. when flaking are you supposed pinch the edges on an anvil with a pointed stick, or have the edge of the rock up and pressing down with the flaking tool?

  2. the potato floats because your solution has reached the proper specific gravity. its pH, however, is still questionable.

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