How to Shellac Bricks

Mix a bucket of warm, soapy water for lightly soiled bricks. Wipe over the bricks, applying the cleaning solution with a clean cloth. Scrub lightly, using a nylon-bristled brush, to remove dirt and debris. Alternatively, swipe over clean bricks with a damp cloth to remove surface dust.

Add 1/4 cup trisodium phosphate to 1 gallon of warm water to tackle efflorescence. Efflorescence, a white powdery substance, results from salts and minerals left in concrete or bricks from evaporated moisture. Scrub the brick surface vigorously with a nylon-bristled brush to wear the powder off the bricks and mortar.

Make a second pass across the bricks with fresh, warm water and a clean or rinsed cloth to remove any lingering trisodium phosphate residue or detergent. Air dry the bricks until completely dry; the bricks will lighten, returning to their previous color, as the moisture content drops -- typically about 30 days.

Dip a paintbrush in a bowl of denatured alcohol for a couple of seconds. Pull it out and hold it over the bowl while it drips, wringing it out as much as possible. While most of the alcohol rapidly evaporates, what is left coats the inner bristles and keeps shellac from sticking as much, aiding in cleanup.

Load the brush with shellac, dipping about one-third of the bristle length into a can of shellac. Tap the excess off of the brush, similar to dumping ashes into an ashtray. Avoid running the brush over the edge of the can to slide excess shellac off; dried and hardened bits of shellac are likely to cling to the brush, contaminating your application.

Begin in the upper corner of a vertical application or in a far corner on a horizontal surface. Glide the paintbrush over the bricks, laying a smooth, generous coat. Working the shellac with a brush to thin the coat only ruins the application. Shellac dries very quickly and excessive brushing will result in a sticky, ugly mess.

Brush back in the opposite direction each stroke completed. Work in small patches to avoid competing with the rapidly drying finish. Blend the edges between each patch, rubbing over the division between shellac and naked bricks with a clean cloth moistened in alcohol. This will melt the edges just enough to feather in the edges.

Apply a second coat if desired. The thicker the shellac, the more the bricks will shine. A thick, even coat of shellac also levels out the surface sufficiently for painting. A light sealer requires a thinner coat. Allow your project and preferences to guide you.

Clean brushes and accessories with either ammonia or denatured alcohol. Throw away left over shellac unless you plan to use it within six months. Shellac decomposes quickly and soon becomes impossible to dry, gradually hardening in the can.