Painting Aluminum on Site

Troubles with painting aluminum surfaces for a commercial fit-out job cause a finisher to seek advice. June 8, 2007

I just finished building a store in a mall. The storefront bulkhead consisted of aluminum composite panels spray painted onsite with glossy red alkyd paint (as specified by the architect) with conventional air gun (painter's choice). The results were a disaster. The paint sagged and ran, there was overspray everywhere despite a good masking job, and the paint didn't cover adequately. We ended up rolling it, which produced acceptable results, but not good results.

We have more of these stores to build and I want a better alternative to what the architect specified. What the owners are looking for is an automotive quality finish on this storefront (don't ask me why they want to do this work onsite, but they do). I have some experience spraying waterborne lacquer with HVLP and this is what I would like to use, but I have never sprayed solid colors in waterborne lacquer, so I don't know if it's possible to tint it deep enough to cover like paint. Someone else has suggested powder coat, but I am unfamiliar with details of the process. Because this is being done inside a mall, I would prefer not to use solvent based coatings.

The owners and architect are adamant that we use their specified products and methods. I can live with spraying onsite, but I want a material that is more spray friendly than alkyd paint. The jobsite ended up looking like the wood chipper scene from Fargo.

Forum Responses
(Finishing Forum)
From contributor B:
What you need is a product specified for metal or alumi-composite material in particular. There are water based products for these materials, but I don't spray metal, so I can't recommend a specific product. But I think Jeff Weis at Target Coatings can. I'm sure that there are other water base manufacturers that offer an excellent product also, such as Fuhr, General Finishes, etc. Maybe someone else can chip in on suggestions. But with my experience on wood, there are very good results from these types of products. And if these are sprayed on site, then water base is the only way to go, in my opinion. These architects need to get with the program.

From contributor J:
This is what happens when architects (and designers) try to mandate finishing schedules. Life would be easier and finish quality would improve if they would stick to doing what they know… But I digress.

I would never try to finish aluminum panels on site. Aluminum requires special primers to make the paint stick, acid wash, epoxy, etc. Not exactly on site friendly materials. Show the owners panels finished in shop with the correct finishes (automotive paints or powdercoat) and see if they do not love the difference in quality enough to talk the architect into changing his mind.

If you are successful in getting them to shop finish and field install, you may need to do some on site touchups if the installers are not careful, but even this is preferable to your current situation. If you do end up having to continue painting them on site, a HVLP or an air assisted airless would be preferable to a conventional gun.