Aluminum Bases are recommended for use with airbrush sizes 0.5mm or larger. A 0.3mm size airbrush may be used when thinned with Auto Air Reducer. Aluminum Bases cover quickly and often only 1 coat is needed. Apply Aluminum Base over a coat of Base Coat Sealer Dark to ensure the that they adhere properly to the surface. The 4000 Series Base Coat Sealers have better adhesion than the 4100 Series Aluminum Bases. Aluminum Bases are made with heavy metallic flakes and may require stirring in addition to thorough shaking prior to use. Aluminum Bases do not have as strong of an adhesion as the other Auto Air Colors.  They are best used for bases without a lot of masking and manipulation. Aluminum Bases need to be cured with heat prior to masking and build up must be avoided to prevent lifting. Substituting the Aluminum Bases with the 4332 Metallic Silver may be desired if heat curing cannot be done or if masking causes lifting. Aluminum Bases do make an excellent base for the Candy Colors but can be difficult to work with if all steps are not followed. Applying a coat of the 4004 Transparent Extender or 4003 Reducer over the Aluminum Base after it has cured prior to masking does help prevent possible lifting during masking. Apply a thin coat of the Transparent Extender or Reducer then cure with heat. The Transparent Extender and Reducer will dry clear and act as a protective barrier between the Aluminum Base and tape or masking film. Another way to prevent lifting of the Aluminum Base during masking is to apply a coat of a urethane intercoat clear onto the Aluminum Base after curing. Like all urethanes, intercoat clears work well with Auto Air Colors.