I am a custom homebuilder. I am in the process of specifying a new brand of exterior latex paint for my exteriors. My question is: What should I be most concerned with when selecting a 100% acrylic exterior latex paint in regard to pigment & the vehicle? What make one paint better than another? Titanium, silicates, acrylic emulsion, water, etc.. There are so many opinions and biases.
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Replies
I did some research on paint a few years back. One of the books I read was Paint in America, published by the National Trust for Historic Preservation. The authors, who are paint experts, said that 100% acrylic, not a latex/acrylic blend, and not an oil, is the best for new work: "The principal synthetic polymers that have been used in emulsion paints are of the acrylic, poly vinyl acetate, and styrene-butadiene classes (and combinations of these). The molecular structure of good acrylic resins renders them more resistant to oxidative degradation than styrene-butadiene and more resistant to water than poly vinyl acetates. They [acrylic] are generally considered the best class of emulsion paints for general architectural use."
So, I would specify 100% acrylic primer and 100% acrylic topcoats. I believe the best sequence is (after washing) prime, caulk, then topcoat. Caulks stick better to primed surfaces than bare materials. I like a 35 or 50 year siliconized acrylic latex caulk. Urethanes are also reputed to be good, but I haven't tried any, though they are common on masonry jobs.
Thank You. I apreciate your time. I surely will consider your suggestions.
I think an alkyd (solvent-based) primer is best for exterior wood, followed up with a high-quality 100% acrylic topcoat. Sherwin-Williams has everything you need.
Well, Sherwin makes good stuff, but if I were you I'd take a good look at Benjamin Moore's premium 100% acrylic exterior topcoat called "Moorglo" (http://www.benjaminmoore.com/wrapper_pg3.asp?L=prod&K=xprods&N=prodext&groupid=11&productid=26#article).
I did a bit of professional painting a few years back and had great success with it (the "soft gloss" Moorglo holds up a little better than the flatter Moorgard). And it's what I painted my own house with. Over bare wood, sanded 80 grit and cleaned, I'd probably go with an alkyd primer just because I know it works great under Moorglo, but Ben Moore makes an excellent acrylic primer, too, which I've also used.
p.s. as I reread my reply I realize I haven't really answered your question--you didn't want another opinion, you wanted facts! sorry--I'm not a chemist, but the bottom line is (depending on what climate your project is in, whether it's near the coast, etc.) you want a topcoat that's both tough and flexible so it can expand and contract--particularly on any south-facing areas. As I understand it that's a primary reason why 100% acrylic is so long-lasting.
Edited 3/9/2004 7:44:45 PM ET by MONSIEUR_ED
Yeah, I haven't tried a water-based primer recently, but my experience with them 20 years ago put me off of them and onto alkyd.
I've had excellent results with Benjamin-Moore paints.