3 lbs Baking Soda
2 lbs Citric Acid
1/2 lb Sodium Lauryl Sulfoacetate
11 oz Caprylic Capric Triglycerides
Desired Fragrance (optional) Too much will make the bombs hard to hold together while they cure*.
Colorant (optional) Food Color will fade with exposure, Mica / Pigments work well.
Phase A :: Sift together, or use your hands, to get out all of the lumps. Be sure and wear gloves, as the Citric Acid will dry out your skin. Work in a well-ventilated area, without air draft, to avoid breathing in the dust from the Sodium Lauryl Sulfoacetate.
Phase B :: Combine to your preference, then add to Phase A, mixing well.
Then press the mixture into molds. We use a two part ornament mold** and only use one half of it. Put some of the mixture in the mold and press it in as hard as you can. Add more mixture and press into the mold. Keep repeating until you have as much mixture pressed into the mold as you possibly can. The more product you can get pressed into the mold, the better the bomb. Turn the mold out onto waxed paper. Tap lightly to release the bomb. You may have to squeeze the mold slightly to get it to release the bomb. Be very careful, as they are very fragile at this time. Do not try and move the bomb but let it sit and cure for 24 hours. At that time the bombs should be wrapped. We place two of the half spheres together to make a ball. Then we shrink-wrap them.
Here is what this recipe will yield:
Small Bombs 60MM are 3.5oz each and use 0.5 lb of base = 11 bombs.
Med Bombs 70MM are 7.6oz each and use 0.5 lb of base = 5 bomb
Large Bombs 80MM are 12oz each and use 1.5 lbs of base = 4 bombs.
You can figure out how much base you need to make to get the number of bombs you need. We like to just roll the remainder into small balls, which won't be perfect but, make the perfect treat to use up left overs. Any left over base will not be any good so make only as much as you need to use in one day. This is not a good rainy day project. You need to be in pretty low humidity to make these come out well.
You can also eliminate the oil and make standard bath bombs, using a spritz of water, or hydrosol, to hold the mixture together. Just mist the powder and then press it together, in your hands. The right amount of liquid will make the powder just hold together when squeezed.
*One way to deal with this is to add Castor Oil, which really helps 'glue' the bombs together and they will cure very hard and last a very long time.
** You can also use any kind of plastic mold that you might find at the hobby store. Another interesting approach is to spray the mixture with a little water, or hydrosol to make it stick together and press it out into a square, then cut into cubes, and spray again, which will make the cubes bubble, slightly, and will look like sugar cubes.