Melt, mix and mix again. That's about all there is to making your own laundry soap. Other than the bar of soap, I always have everything else on hand so it's cheap and easy.
Here's how you do it:
Grate a bar of Fels Namptha soap on the fine side of your grater. Someone will walk by and try to eat some because it looks like cheese.
Pour 4 cups of boiling water over it and put the pan on the stove on medium low. Watch it carefully, and stir often, you don't want it to boil. It makes a huge mess, trust me.
While it's melting, mix together 1 cup of washing soda and 1/2 cup of borax with about a gallon of water. Guessing the amount of water is fine, you just want to get it mixed up really well.
Now the soap should be all melted and you'll just dump it into your borax/washing soda/water mixture and stir. It will start to gel up and kind of look like....well, snot. For lack of better word to describe it. I have little kids, snot is the best comparison I can make. Sorry.
Now you just fill the bucket up and put the lid on. Let it sit and cool off over night. The next day it will be really gelled up and look strange. Don't worry! That's what it should look like :) The hardest part though, is mixing it after the whole bucket is full. I use a paint, or drywall mud, stirrer for a 5 gallon bucket. They look like this:
Just mix the detergent until it all looks the same and there aren't any big lumps left.
And that's it!
You made soap. For top loading machines, add 1/2 cup to the washer, for HE or front load washers, use 1/4-1/2 cup depending on how dirty the clothes are.
I'll show you how to make homemade bleach alternative next. You can add it to your clothes to really boost the cleaning power of this laundry soap!