Aluminum Gutters Can Be Painted
DEAR TIM: Many years ago, I had white aluminum gutters and down spouts installed on my home. They are in great shape except for the faded paint finish. I want to change the color scheme of my home. Can I paint the aluminum surfaces and if so, what is the best way? I am thinking of pressure washing the entire exterior surface of my home before painting. Is this a good idea? Leslie M., Linden, NJ
DEAR LESLIE: I have got good news and bad news. Let's start with the good news first. The aluminum gutters can be painted and quite easily at that. It is not hard to do, but if you make a mistake, the next time it rains they will look like a blistered hot dog sweltering on a grill at a Fourth of July picnic.
Much to the surprise of many people, metal surfaces actually are very compatible with paint. Just look around you at all of the painted automobiles, appliances, and commercial steel buildings and metal roofs. Aluminum is especially paint-friendly as you have witnessed on your own home. Since it doesn't rust, blistering or peeling of factory applied paint finishes on aluminum is very rare.
The key to repainting aluminum gutters and down spouts is making sure they are clean and that you use the right primer. Now it is time for the bad news. Pressure washing the gutters and down spouts and the rest of your exterior surfaces is simply not the best way.
Proof of this statement is available in two forms. When you shower each day, I would venture to say that you do not just rotate in circles in the shower allowing a vigorous stream of water to do all the work. You most likely rub your skin with soap and water and then rinse with the water stream.
Do you want more proof? Take your car to a self-clean car wash equipped with pressure washers. Clean your car allowing the tip of the pressure washer to get as close to your car as you feel comfortable. After leaving the car wash, pull out into the parking lot and let the car air dry. Take your fingers and wipe them across the paint. I guarantee you that you will remove a layer of dirt that was left behind by the pressure washer.
Wash your house and the gutters and down spouts as you would your own body. Use large grout sponges or scrub brushes. Purchase grout sponges at ceramic tile stores. I prefer to use liquid dishwashing soaps as they make lots of suds. Be sure to scrape any loose paint before you wash. If you have wood on your home, you will probably need to scrape a second time after washing. Paint adjacent to bare spots of wood always seem to pull away once the rinse water dries.
After the gutters and down spouts are dry, they still may be chalky. This is normal. The chalk is simply pigment particles at the surface of the original paint. You have now reached the most important part of the job - the primer. Avoid using any latex paint primer that contains ammonia. This ingredient is often listed on the paint can label or a technical sheet that the paint store has on file. Ammonia can react with oxidized aluminum that is hiding inside small pin holes or bare spots on your gutters and down spouts. When this happens, the chemical reaction creates a gas bubble just beneath the skinned over latex paint. The next time the air pressure drops in advance of rain storm or shower, the bubbles actually inflate! When the pressure rises as the weather clears, the bubbles mysteriously disappear.
There are two primers that work great for faded aluminum. Try to locate a clear acrylic bonding primer that actually penetrates the chalky aluminum. This product forms an excellent foundation for a final coat of 100 percent acrylic paint.
If you can't locate this nifty clear primer, then use regular oil base metal primer. The trick is to thin the primer with 16 ounces of thinner per gallon of paint. Feel free to add some pigment to this primer if you feel it will get you close to the final color of your trim. Try to apply the final coat of paint within 48 hours of applying the primer. The top coat paint will bond much better if you can do this.