You need distilled water, glycerin, diethylene glycol, dipropylene glycol, propylene glycol, and triethylene glycol. Distilled water is necessary because regular or mineral water will clog a fog machine.
Glycerin can be purchased at pharmacies or chemical supply stores. The four glycols can be purchased in the home department of a chemical supply store.
Use 15 to 35 percent glycols, mixed with distilled water. Try a small amount in the fog machine to test it. If you would like a thicker fog, add more of the glycols.
Do all mixing in an open space to prevent any inhalation hazards during fog juice creation.