The night before you want waffles, put into a large mixing bowl (such as a KitchenAid mixer bowl)

your sourdough starter (I usually have about 2 cups)

3 1/2 cups water

5 cups all purpose flour

2 teaspoons instant yeast

2 tablespoons sugar

Stir to combine (I use a wire whisk for this). Set it out on a counter, at room temperature, with a plate over the top of the bowl. If it is warm, it may bubble over, so sometimes I put it on a rimmed cookie sheet.

In the morning, the dough will have risen a bit and be bubbly. Stir it down and remove from the mixture the same amount of starter that you used the night before, and put it in the refrigerator in a clean container.

Add

1'2 cup sugar

1 can (12 ounces) condensed evaporated milk

4 eggs, lightly beaten

1 cup vegetable oil

2 teaspoons salt

2 teaspoons baking soda

Stir until combined, and let it sit for at least a few minutes before you start baking the waffles. They will be very light.  Eat them as they come off the waffle iron; don't store them up in the oven until there are enough for everyone.  Bake the entire recipe after breakfast and cool the extra waffles on wire racks.  Then put them into Ziplock bags and into the freezer.  They heat up easily in a toaster/toaster oven, and even the microwave if you don't care about their not being crispy. 

I've seen a few directions for creating your own sourdough starter. I think the following link does a very good job of making your own starter:

http://whatscookingamerica.net/Bread/SourdoughStarter.htm

Easier than making your own starter is getting some from a friend. I have shared my starter with many people. I get a clean glass or ceramic container with a lid and put about 1 1/2 cups of my starter into it for my friend. Then I add 3/4 cup flour and 3/4 cup water to my remaining starter, stir until mixed, and put it back into the refrigerator. When you store the starter in your refrigerator, and if you do not use it often, t will turn dark gray. Do not throw it away. It is still good. Just stir it up, and the dark color will disappear.