Things You'll Need
2- to 4-inch natural-bristled paintbrush
2- to 4-inch nylon paintbrush
Acrylic latex paint
Acrylic caulk is appropriate for painted surfaces, because it is well suited for adhesion. Unfortunately, inexperienced do-it-yourselfers often choose non-paintable caulk instead. Non-paintable caulk is made of clear silicone. If you apply paint directly over untreated silicone caulk, peeling will inevitably occur. Fortunately, you can paint non-paintable silicone caulk as long as you treat it with a special base primer. Employ the right preparation procedure, or you will have little chance at paint adhesion.
Rinse exterior non-paintable caulk with a pressure washer. Use damp rags if the silicone caulk is located indoors. Allow at least two to four hours of dry time.
Purchase an oil-based primer that is compatible with latex topcoats. Coat the non-paintable caulk with the oil-based primer. Apply the primer, using a paintbrush that has natural bristles and is engineered for use with oil finishes. Wait two hours for the primed caulk to dry.
Wash the brush with mineral spirits. Do not use tap water, as this will damage the brush.
Coat the primed non-paintable caulk with latex paint, using a nylon paintbrush engineered for water-based finishes. Finish exterior non-paintable caulk with acrylic latex paint. Wait two hours for the finished caulk to dry.
Wash the brush with water. Do not use mineral spirits, as this will damage the brush.
Kilz manufactures an oil-based primer that is compatible with latex topcoats.
Most oil primers will reject water-based latex paint. Examine the label to ensure that the oil primer you select will work with water-based topcoats.
Do not paint over unprimed non-paintable caulk, or adhesion problems will result.