Painting Aluminum Siding

[Hawkeye]

I have aluminum siding that is chalking heavily, but is in good shape otherwise. Over the last week or two, I have scrubbed away most of the chalk to the point where I can rub my hand over it and nothing comes off, and I can see some small areas of bare metal that is now exposed. I am ready to begin painting but am not sure the best way to proceed from here. I have read some advice that says if the aluminum siding has been prepped well, an acrylic latex can be painted on with no primer needed. However, I read on another site that there are ingredients in the acrilyc latex paint that can react negatively with the aluminum siding and cause the paint to fail. Because of this, I am considering using an alkyd primer with an acrilyc latex top coat. Would this work well or am I making more steps for myself for no good reason?

[Jake]

Personaly I don't think that priming is ever a bad idea.

Lightly scuff, use a decent bonding primer (Zins 123 or if you wanna go hard core some XIM), and hit it with some latex...

You should be just fine!

Good luck! 

[rmichael]

Hawkeye,

Acrylic paint and aluminum were made for each other... in fact, Glidden paints used to advertise that point with this bold label on their acrylic latex paint " Great for Aluminum Siding".....     You can apply the acrylic latex directly to clean aluminum gutters with confidence but if you are wish to prime use a good quality latex primer like Zinsser 123, I would not recommend using a full alkyd primer, it is best to have a coating structure with like binders ( acrylic + acrylic)
I have never had a problem using acrylic latex paint on clean ( and dry) aluminum gutters.. 

Best Luck,
rmichael

EDIT: Missed the "bare metal" reference... If the "bare spots" have oxidized spot prime them with an alkyd primer then prime and/or paint the complete project with the acrylic...

[Hawkeye]

Ideally, I would like to use water based primer underneath the top coat to keep both layers similar, but I only considered using the oil primer when I read about problems with latex primer and aluminum siding...something about the latex causing gas bubbles to be released when painted over the aluminum siding. I agree that oil underneath latex just doesn't seem like an ideal route to go though either, so in the end I'm left with two options that each have their potential downsides. I'm starting to feel a little better about using a latex primer now though after coming across this forum. There's a lot of misinformation out there and it's hard to figure out what to believe when you're just a DIY'er like me. Seems like there's a lot of smart people here that know what they're talking about though 

[rmichael]

Hawkeye,

The confusion is comparing coated aluminum and raw oxidized aluminum...  Aluminum siding and gutters usually have a factory coating (paint), this coating will chalk over time and require painting. Once the aluminum is clean of dirt and chalk acrylic latex is an ideal paint for the surface.

If the aluminum is raw ( no coating ) and especially if it has become oxidized ( weathered) there can be a reaction between the raw oxidized aluminum and the ammonia in the latex paint. If your gutters have raw areas I recommend that you spot prime them with an alkyd primer then apply an acrylic primer to the entire gutter followed by an acrylic latex top coat...

Best Luck
rmichael

[Hawkeye]

That clears up the remaining questions I had. Many thanks!