Summary for painting aluminum columns Discussion
Painting aluminum house columns can fail if the coating system does not bond well to the metal. John McGlinn said his two aluminum front columns were painted twice over two summers, but each time the finish cracked and peeled down to bare aluminum when cold weather arrived. The answer notes that paint adhesion on aluminum is often difficult and that manufacturers can use chromate films to improve bonding, which cannot be duplicated at home. The practical advice is to remove all the old paint, then visit an automotive paint supply store and ask for a primer specifically suitable for aluminum. The responder says the primer may need to be sprayed, and that the store staff can advise whether the topcoat should be sprayed or brushed. The key point is that the failure likely came from the coating system, not just the weather, and the fix is proper surface prep plus the right aluminum primer.
Q. I have two aluminum columns in the front of my home that I painted over the summer. Now that the cold weather is here they have started to crack and peel right down to the bare aluminum. Could you help me by telling me what I have done wrong? Also can you tell me how to do it right? Do I need to sand down to bare aluminum? Use a special primer/additive? Should I spray or brush it on? I have done this twice over the last two summers. It has peeled and cracked both times when it gets cold.
Thank You
John McGlinn
homeowner – Hatfield, Pennsylvania, USA
2005
 | A. Paint adhesion over aluminum can be a real problem. Manufacturers can apply chromate films to achieve good adhesion, but you can’t do this at home. I’d suggest you have to remove all the old paint, then go to an automotive paint supply store and ask them for a primer suitable for aluminum. You may have to spray this – they will tell you how to use it. Once you have the primer on, you can spray or brush – ask the guys at the auto paint store about that too.
A. The paint is cracking due to your columns expanding and shrinking due to changes in the weather, I am going to guess that you are using either plain spray paint or a petrol based paint. For starters, sand them down to the bare metal, then you DO need to prime them, then paint. I would suggest an epoxy based paint for the finish (very robust and durable when done properly). Conversely you could pickup some Rustoleum lawn furniture paint (the ones for metal), that would possibly hold up better, but I would still go with my first suggestion. Marc Banks |
