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.
California Paint makes a Grip Coat Bonding agent or primer that's supposed to bond to any surface including metal, vinyl, glass, aluminum and copper. We will use this as a base coat of course after properly prepping the garage doors which includes scraping all the loose, chipping or peeling paint and sanding scuffing up the doors. This is an acrylic paint and can withstand up to 160 degrees of heat. I highly doubt that the sun will bring the temperature even remotely that high so that shouldn't be a problem. We are also going to do an adhesion test before painting the doors. to make sure it will adhere properly.