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.
Acrylic paint consists of pigment that uses mineral spirits and acrylic resin for mixture and suspension. In contrast to oil paints, acrylic paints are extremely fast-drying and, in some cases, require only 60 seconds to provide a dry surface. Many acrylics are noted as drying down at a slightly darker color.