westend wrote:
Aluminum should be acid etched and then alodined prior to priming.
A 2 part epoxy primer and a polyurethane top coat like Imron is overkill for a travel trailer but would last forever.
Instead of using a process used for airplanes, I think the OP would be better served by advising to paint like residential siding.
Yes, two part epoxies and Imron would get a durable finish but I wonder how many of those advising this have used Imron or it's specified primer? Besides the cost, a user of Imron is facing some big safety concerns. The stuff is just flat-out hazardous in it's liquid form. Special mask cartridges should be used. I've painted with Imron and for everyday painting jobs, I wouldn't suggest to use it.
The same advice would be given for lacquers, epoxies, and urethanes used for auto body work (unless the user has experience, tools, and time).
For the uninitiated to painting, buying one of these 3M masking dispensers and some paper is going to be the best $30 ever spent.
I DID say overkill.:)
As far as hazardous.....only if you don't take precautions.
Why does the best stuff always have to be the most hazardous?
Pisses me off.
In any event...I've worked with many different types of polyurethane in my past career as an aircraft painter. Imron is the most readily available for the average guy AND does a great job. But yes...expensive.