Paint Sand Texture
Preparation to paint a sand texture. Both latex and alkyd paints, including floor paints need to have the surface primed before being applied. Paint is designed to work with a primer. Using a primer will save you money in the long run because improves adhesion of the topcoat. This helps prevent peeling or chipping. Primer gives the paint finish a uniform and even sheen. Hinders water, oils and grease stains from bleeding through your topcoat. For new wood, you can use a general latex primer. If your lumber is old use a stain-blocking primer. Clean the surface of the wood before priming. If you have mold or mildew growing on the surface, use a 25% bleach solution to kill it. Nails should be removed.
Unseasoned lumber. Moisture in the lumber needs to be removed. Dry the wood before painting the sand texture. Place the wood in a warm room with circulating air for a few days. Expansion/contraction causes the holds to loosen and spin, may cause the paint to blister or peel, and contributes to mildew which causes the wood to weaken and have a musty odor.
Humidity. A damp basement is often caused by moisture condensation from humid air onto cooler surfaces or may indicate that repairs or additional insulation are needed. Some basements are continually wet from water leaking through crevices in the wall. If you will be installing your climbing wall in a location with these conditions (such as a basement, cellar, shed, etc) you can take steps before construction to lower the water content of the wood, prevent mildew and prolong the life of your wall. Wipe the surface of the wood with Trisodium Phosphate or with a 25% solution of bleach and soapy water. Improve ventilation at your climbing wall and make sure there is sufficient lighting. Trisodium Phosphate is available in most paint stores. Many latex paints have fungicides added to help combat mildew attack. Check the manufacture's label.
Bleeding. Latex paints are water-based, which can cause rust. Use galvanized screws and bolts for construction. Nails should not be used, except to temporarily tack pieces together, then removed, so non-galvanized nails are ok if used only temporarily.
Protect Non-painted Surfaces. Use a drop cloth, plastic or tape to cover items that should not be painted. For example, if you have an adjustable section, the moveable sections should not be painted. Protect the floor for paint/sand texture drips. Cover the floor, even if it is a cement basement or garage. Your product will look much more professional if paint drips are not all over the floor.
Sand Texture Mixture. Use a ratio of about 10 to 1 paint / sand by volume. Add or subtract a little as necessary to get the texture you want. Sand settles to the bottom of the paint very quickly. Each time you dip the roller in the bucket, twist and plunge the roller to re-mix the sand / paint so the texture will be even.
Application - Painting Sand Texture. Take the added precaution to plug the t-nut holes. Both sand texture in latex and alkyd paint may prevent the bolt from catching the threads. To protect your t-nut threads you can plug the holes with golf Tees. Golf Ts are cheap and can be obtained easily in large numbers and work well to plug the t-nut hole, and can be removed easily when done. Start painting the sand texture at the highest locations and work down. Apply paint/sand texture with a roller in a lengthwise direction to the sheet sheathing. Apply paint / sand texture in one direction, then even out the roller marks by rolling at a 90° angle. With light pressure on the roller, go over the panel again at the original direction (lengthwise to the panel). This application method will work well to apply sand texture. For edges you will need to cut in with a paint brush. Slap the brush lightly to get the sand texture to come off the paint brush.
Sand Texture Design. Make rock-like patterns using a trowel, brush, or sponge. Experiment on scrap plywood left over from construction. Differing degrees of pressure to the applicator will make different patterns. If you are not happy with the way it looks scrape it off and try again. It's best to test and work out the pattern, tools, paint/sand ratio before you begin texturing.
Cleanup of the sand texture. For latex paint cleanup, wash your rollers, roller frames and brushes with mild detergent and warm water and clean up any equipment used according to the recommended instructions. Cleanup of alkyd paints requires more work and the use of mineral spirits as thinner. Disposal of waste thinner and paint presents an environmental risk.