Water Level Controls and Devices. A water column is used on a steam boiler to reduce the turbulence and fluctuation of the water level so the gage glass can provide a steady, accurate water level reading. The use of a water column is not mandatory.
Preparation. Verify the paint is completely dry. Never use varnish to seal acrylic paint if it is even slightly wet. Dust the surface of the dry paint gently with a clean cotton rag or paper towel. Rinse a jar or cup with water to remove any dust particles. Read the label on your varnish to find the correct water-to-varnish ratio. Mix the varnish with water in the jar or cup.
Terra cotta is porous, so water will come through the pot unless one of the following methods is used: - Patio Paint (see above) - If you want to paint the pot with acrylic paints, first seal the inside of the pot with Exterior Varnish or Terra Cotta Sealer. You may then paint the outside of the pot with acrylic paint.