Liquitex - Techniques

Mural Painting: Surface Preparation

MURAL SURFACES

False and Separate Walls

The best support for mural painting is a false wall erected in front of an existing wall.
This eliminates the dangers inherent in expansion and contraction of plaster and masonry. It also protects against cracking, peeling and water damage and allows for easy removal of the mural.
The mural wall can also be a stretched canvas panel or canvas adhered to a rigid panel. A false wall for interior murals allows the artist to paint the mural in the studio rather than on location.

Murals can also be painted on existing wall surfaces. Proper surface preparations must be observed to insure longevity of the mural.
A surface that has been previously painted will not be as permanent as a surface that has never been painted or has been stripped of all existing paint.
The surface must be free of any previous oils and silicones or paint may peel. Paints and oils can be removed with the proper solvents or by sand blasting before painting.
Surface must be "dust" free and not subject to extreme moisture behind the wall to be painted (unless waterproofed).

SURFACE PREPARATION

The longevity of a mural is directly related to the surface preparation.

Selecting a Surface

It is important that the surface does not contain moisture. New concrete may not be free of moisture for 2 to 3 months after drying.
Make sure the surface will not get wet from water seeping through existing outside walls. Moisture can be absorbed behind a substrate and cause the paint to peel from the surface. (A leading cause of failure)

Cleaning the Surface

There must be no grease, wax or oil on the surface and the surface needs to be structurally sound and free of loose particles and dust.

1. Remove all existing loose particles or damaged painted surfaces. If the wall has been painted with oil paint or is peeling, strip all existing paint.

2. If the surface has been painted with acrylic paint, sand entire surface.

3. Clean surface with a degreaser, such as TSP mixed with warm water.

4. If mold or mildew is present, use a stiff brush and scrub with a mixture of 1 part bleach and 3 parts water. Rinse twice with warm water and allow to fully dry.

Applying the Ground (Priming the Surface)

After the surface has been cleaned, it must be prepared to accept the paint.

Fixing Cracks and Uneven Surfaces

For smooth surfaces: Brush on one coat or spray two coats of Liquitex^® Matte Medium.
For rough surfaces: Trowel on one-two coats of Liquitex Matte Gel Medium.
Allow to fully dry. Mediums are clear/ translucent when dry and cloudy/milky when wet.
Painting can proceed over these sealing coats, however at least two coats of gesso are recommended.
Most artists prefer a white surface to use as a basis for the mural cartoon or sketch and to establish color relationships.(By using gesso)

Priming The Surface

Apply Liquitex Acrylic Gesso for a white ground, Liquitex Colored Gesso for a colored ground, or Liquitex Clear Gesso to maintain some visibilty of the original surface.
If necessary, thin gesso with no more than 50% Matte Medium. Brush or spray apply.
For spray application, thin gesso with a mixture of 50% Matte Medium and 50% water. This mixture reduces tooth and absorption. Over thinning with water alone can cause cracking or result in poor adhesion.
Multiple coats of gesso can be applied and wet sanded to produce a smooth ground. Wet sanding will make a flexible surface (canvas) somewhat brittle.

Various Mural Surface Preparations
New Wood: Sand surface. Seal with 1 coat of Matte Medium. Apply 1-2 coats of Gesso.

Paint with Medium or Heavy Body Artist Colors. Apply isolation coat of Gloss Varnish. Let dry 48 hours. Apply 1-2 coats of Matte or Gloss Soluvar^®.

Painted Wood: Remove loose material. Sand or Strip. Seal with 1 coat of Matte Medium. Apply 1-2 coats of Gesso. Paint with Medium or Heavy Body Artist Colors. Apply coat of Gloss Varnish. Let dry 48 hours. Apply 1-2 coats of Matte or Gloss Soluvar.

New Masonry: Must be dry, cured, and dust free. Apply Matte Medium for smooth surfaces, Matte Gel Medium for rough surfaces. Apply 1-2 coats of Gesso. Paint with Medium or Heavy Body Artist Colors. Apply isolation coat of Gloss Varnish. Let dry 48 hours. Apply 1-2 coats of Matte or Gloss Soluvar.

Painted Masonry: Remove loose material. Clean. Sand or Strip. Must be dry and cured. Apply Matte Medium for smooth surfaces, Matte Gel Medium for rough surfaces. Apply 1-2 coats of Gesso. Paint with Medium or Heavy Body Artist Colors. Apply isolation coat of Gloss Varnish. Let dry 48 hours. Apply 1-2 coats of Matte or Gloss Soluvar.

New Sheetrock: Apply an acrylic emulsion compatible industrial sealer such as Aqualock^TM.

Unprimed Painted Metal: Remove grease, dirt and solvents. Sand surface. Wash with a prep solution for the painted metal being used. Apply an acrylic emulsion compatible primer (auto parts stores are a good source). Apply Matte Medium for smooth surfaces and Matte Gel Medium for rough surfaces. Apply 1-2 coats of Gesso. Paint with Medium or Heavy Body Artist Colors. Varnish with isolation coat of Gloss Varnish. Let dry 48 hours. Clean with mineral spirits and apply 1-2 coats of Matte or Gloss Soluvar.

All contents ©1999-2009 Liquitex Artist Materials. All materials are provided for non-commercial, educational use. To contact Liquitex, e-mail us, or call 1-888-4ACRYLIC (1-888-422-7954)
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