Petroleum oils
Light-bodied plain petroleum oils provide good release and produce uniform concrete color. May leave more bug-holes than other release agents and if over applied may stain concrete. Relatively inexpensive petroleum oils with an added wetting agent reduce bug-holes. They can be used on all types of formwork.
Emulsions
Emulsions contain a water phase and a water-insoluble phase. All emulsions freeze in cold weather. Usually they cost less than plain oils.
Water-in-petroleum
Emulsions of water in petroleum oil where the external phase is oil. For all types of formwork except steel; especially for absorbent forms such as wood.
Petroleum-in-water
Emulsions of petroleum oil in water where the external phase is water. Excessive application may cause severe retardation, discoloration and dusting. Inexpensive but not widely recommended.
Other emulsions
Emulsions that contain little or no petroleum oil. Polymer-in-water emulsion is an example.
Non-reactive coatings with volatile solvent
Volatile solvent is derived from petroleum. Active ingredients may be waxes silicones, synthetic resins or water-insoluble soaps, petroleum solvent evaporates so it cannot stain concrete. Tend to be more expensive than oils or emulsions.
Waxes
Good for forms made of concrete, excellent release characteristics but difficult to apply. Wax residues on formed concrete surface can prevent paint from adhering. Emulsified waxes are easier to apply.
Chemically active agents containing fatty acids
React with alkalis in concrete. Reduce bug-holes. Those suspended in volatile distillate dry on form face and resist wash-off by rain. Excess application can cause dusting of concrete. More expensive for given volume, but rate of coverage is often greater.
