When it comes time to paint aluminum siding, the secret to success is choosing the right paints for the job. In this case, you will need an oil-based paint as well as an acrylic-based paint. The oil paint will act as a barrier between the acrylic and the aluminum itself. This precautionary step is necessary due to the fact that acrylic paints contain ammonia. Ammonia and aluminum cannot come in contact with each other because it will create a gas. This gas will then form small bubbles between the surface and the paint itself. which may lead to premature peeling and fading. The remedy for this is to properly prepare and prime the aluminum siding surface with an oil primer and then finishing with the acrylic.
Step 1 - Prepare the Aluminum Siding
Fill your bucket with water and add powdered soap. Laundry detergent will work fine. Wash by scrubbing the aluminum siding until there is no color left on the sponge or in the water. Rinse well, without using too much pressure. There should be no dirt left to wash off with a high power spray. The goal of rinsing is to remove all the residual soap.
Allow the siding to dry completely.
Step 2 - Check Outdoor Conditions
For best results, you will need to schedule your paint day for a time of cool overcast days with no wind or rain in the forecast. This is due to the fact that rain, wind, or sun can affect the "dwell" time (soak time) of the paint as it dries. The paint needs to dry at a slow pace, without heat or cold, to ensure the best bond to the surface.
Step 3 - Prepare Primer and Paint
Add one pint of paint thinner to the gallon of oil-based metal primer paint. Since the oil paint does not cause a reaction with the siding this paint will act as a barrier between the aluminum and the acrylic finish paint. You may want to tint the primer with a lighter hue of the finish color for easier color application.
Allow the primer to dry but the finish paint needs to be painted on the primer within 48 hours for best adhesion.
Step 4 - Finish with Final Coat of Acrylic Paint
When purchasing an acrylic paint shop for the two most important features. Be certain you have an exterior acrylic paint and it must be a 100 percent acrylic latex exterior house paint. Buy the best you can afford. The goal is to buy paint containing the highest level of acrylic paint resin.
Resin is the liquid plastic that is added to acrylic paint to give it its bonding and surface protective qualities. The higher the resin content the better the overall durability. Most paint cans will have the percentage of resin content written on the can.
Use the paint as it is directly from the can. Do not thin with thinner.
If weather permits and you have followed these simple steps to paint aluminum siding the results will be a long-lasting, trouble-free surface.