Lesson 3: Stenciling with Plaster
Basics for Outdoor Plaster Stenciling
Outdoor plaster stenciling gets a lot more abuse than indoor work. It has to be able to stand up to wind, rain, show and drastic changes in temperature. So for outdoors we use different materials. The first is wood putty that comes in a powdered form. Sometimes it is called water putty (which dries to a yellowish finish) and sometimes Fix-all (which dries white). Both are far stronger than joint compound and so more suited to outdoors. Mix these up with 1 part white glue and 2 parts water until it reaches the desired consistency - thin enough to spread easily but thick enough not to run when troweled onto a vertical surface.
"Stucco Repair" also holds up well and will stick to bare wood - perfect for newly built flower boxes and planters.
You will need something to mix the putty, glue and water in, and a stick for stirring, as well as a trowel, and, of course, your stencil. When finished spray with an interior/exterior clear finish for added protection.
As to coloring options, your best bet is either to paint both your stencil and surface a single color with exterior grade paint, or to tint with acrylics formulated for outdoor use. You can also use powdered masonry colorant (NOT the liquids) to tint your plaster. Be aware that these masonry colorants appear deeper when dry than they will when you are working with them, do go a bit lighter than your desired final color.
I haven't tried using these on less porous surfaces such as glass, but hope to experiment with it. Imagine the interesting things you could so with raised plaster on mirror - or framed.
