GACs can be blended with GOLDEN Acrylic Paints to extend the paint, regulate transparency, create glazes, increase gloss, reduce viscosity or improve adhesion and film integrity. The GAC polymers can also be used for binding pigment solids for various effects and surfaces. Unlike the other GOLDEN Mediums and Gels, GAC Acrylic Polymers have only a minimum amount of thickeners, levelers, defoamers and surfactants to ensure good film formation.
The consistency of the GAC polymers is very fluid, and thinner than other GOLDEN Mediums. Since they do not have thickeners added, these polymers will reduce the thickness of most GOLDEN Acrylic Paints. GOLDEN Fluid Acrylics are slightly thicker than the GACs, but will be the color line least changed in viscosity with any addition of a GAC polymer.
GAC polymers should be gently stirred or rocked back and forth prior to use, but should never be shaken, as this will incorporate significant amounts of foam which will be very difficult to eliminate. Foam can severely affect the transparency of the film causing an apparent foggy or hazy quality. When applying with a brush, use minimal agitation and force, and do not overwork, as this too will result in foaming.
If spray application is desired, blend with GOLDEN Airbrush Medium. Start at 2 parts GAC Medium to 1 part GOLDEN Airbrush Medium. When faster drying is required, replace the Airbrush Medium with GOLDEN Airbrush Transparent Extender.
The GAC polymers are milky-white and relatively opaque while in the wet state, but when completely dry they will become transparent/translucent.
The amount of time that an acrylic takes to dry completely is dependent on several variables, including film thickness, ambient temperature and humidity, air flow patterns and the absorbency of the support. A relatively thin film (approx.1/16 inch) may take from 10 hours to 4 days to lose the milky quality, while a film 1/4 inch thick may take 2 to 10 days or more. It is important to note that film clarity occurs before the film has completely dried, or cured. The thin film mentioned above will take 2 to 3 weeks to achieve complete dryness, while the 1/4 inch thick film will take 2 to 4 months. This is very important to consider when determining how artwork is to be stored. When film transparency is critical, artwork should never be stacked or subjected to high humidity conditions (For a more complete picture about the acrylic drying process, refer to GOLDEN Information Sheet: Technical Notes on Drying).
The GAC polymers are intended for use as binders, modifiers or additives for acrylic paints. They are not intended for use as a final varnish. Golden Artist Colors manufactures two different varnish systems, Polymer Varnish and Mineral Spirit Acrylic (MSA) Varnish.