I’ve been making my own laundry soap for several months now. I couldn’t be happier with the results, especially in the stain management category (extremely important when you have a toddler who delights in acquiring new and often inexplicable stains).
So, while mixing up a third batch this weekend, I took the leap and made dishwasher detergent, too. I mixed equal parts baking soda and Borax, and we used two tablespoons per load.
I think there are always trade offs in projects like this. Excess Borax in the ground water is not great, but many believe it’s better than the chemicals found in other detergents. Plus, we’re avoiding those bulky plastic containers altogether.
Because in this case the Borax would be coming in to contact with our dishes, I wanted to be absolutely sure it was safe. I read a number of papers and articles on the matter, then shared my findings with Bryan, a guy who won’t eat leftovers past the 24 hour mark for fear they’ll kill him. He signed off, assuring me Borax was not toxic. However, to ensure a super clean rinse, I added vinegar to the Jet Dry dispenser.
I’d welcome any feedback or links to additional research on the topic. In the meantime, we’re all still upright, and we’re really happy with how well this works. I’d strongly suggest avoiding the leftover chicken in the fridge, though, if you’d like to make it until the weekend.
Smith Family Weblog 
Posted by Chuck on October 20, 2010 at 8:35 am
Interesting. But where’s the soap in your soap? I think that borax and soda are meant to enhance the cleaning power of soap, not replace the soap.
If u decide to add some soap to your soap – this looks interesting: http://www.cavemanchemistry.com/scisoap.html
Posted by Rebecca on October 20, 2010 at 9:55 am
That’s a good point, Chuck. In the laundry soap Fels Naptha is the soap. I looked back through all the “recipes” online for dish soap, and these seem to be the two primary ingredients. (Some add citric acid.) So, you think we’re not actually “cleaning” the dishes, just rinsing?
Posted by Chuck on October 20, 2010 at 10:27 am
Soap has an end that sticks to fats and an end that sticks to water. This is what allows the water to pull the fat off the dishes and down the drain.
I have heard that organic acids like citrus acid (and vinegar) can be soap-like when in a alkaline solution. The borax and soda create an alkaline solution. Maybe the vinegar is doing all the cleaning.
Or maybe you are making soap in the dishwasher. Soap is made by cooking fat in alkaline solution. The dishwasher water gets pretty hot. Much hotter than the clothes water.
Also I read that borax makes peroxide. Peroxide is pretty corrosive. That would aid in cleaning (and etching).
You could try getting all science-y and stuff. Just try different combinations and see what happens. Maybe it will get u on Mythbusters!
Posted by Rebecca on October 20, 2010 at 9:49 pm
Chuck, you are awesome.
Posted by Nicky on October 21, 2010 at 7:00 am
On the soap-making front, you don’t actually “cook” the fat in an alkaline solution. When you add oils to a very strong sodium-hydroxide solution, the reaction makes it heat up by itself.