Painting Pros: latex/oil, spray or roll?
Getting ready to paint part of an old Victorian in the San Francisco area. A lot of replacement and repair on this part of the house. What we will paint in the next week has been sanded clean, patched and sealed. Latex or oil is the question, and roll or spray? Weather’s been good for us so far: highs: 70s, lows 50s.; no rain.
Replies
Latex. Oil is nigh impossible to find today, and latex holds up better anyway. Spray is faster, but brush and roller also works. Your choice.
I've heard that latex is best 'cause it breathes, AND 'cause it's available. However, my contractor & painter both told me that oil-based primer is best outside, especially on bare wood. Any thoughts on that?
Also, my experience on wood is no matter how you apply it, it's good to backbrush.
I'd use an oil-based primer if I could find one. But what really matters is the top coat, latex or acrylic doesn't "breathe", but you're on the right track because it remains more flexible over time than oil.
According to the scientist that wrote Paint in America modern 100% acrylic paints are longer lasting than oil based paints. He explains the reasons in the book. The book is packed away so I can't look up the specific quote. Consider yourself fortunate that you can start over with acrylic.
100% acrylic paints are better than blends of acrylic and latex.
But in how good of condition of the surface of the old wood?
We took this area done to bare redwood, replaced any defective, unsalvageable pieces of siding (1x8 V-rustic), used a 2 part epoxy sealer, and 2 part patch, sanded and feathered out all highly visible areas. A lot of work!
It sounds like you've done one of the most thorough surface prepartion jobs that can be done. I think I understand why you are proceeding carefully in selecting the primer.
I know the VOC regs have hit California hard, but around here (MN) the most durable paint job will come from using an alkyd primer with two coats of ####100% acrylic latex.
I use Ben Moore -- Moorwhite primer, and MoorGlo latex.
I agree that old fashion oil house paint would not be good, but this kind of oil (alkyd) primer is specifically formulated to be top coated with latex.
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"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
saw, I agree that latex is now the best way to protect exterior wood, but there's something else you should know. When you're painting any house that's been around for a century, there's gonna be a buildup of old oil paint. When it gets thick enough (like 8-10 coats) and you put on ####thick couple of coats of latex, you might have problems.
The properly applied latex will bond firmly to the old paint - which is good- but latex moves with heat and oil doesn't, which is bad. The result will be that soon after the job is done, daily heating/cooling cycles can cause the new paint to pull the old paint right off the wood, and you'll see mysterious blisters, or bubbles in the new paint. If latex has been used already, you may have noticed this phenomenon.
What to do? The way I see it, you've got four options: 1. ignore my warning, paint, get paid, and never drive down that street again. You might even get lucky. Or,2. Completely strip the paint down to the wood (but please be careful with the lead dust -no joke), prime and paint with acrylic latex, or, 3. Because you still can, use oil based paint and defer the problem until they paint the whole place in a couple of years, or 4. minimize the risk by using oil primer, tinted, and thus require less latex on top. The thicker the latex, the more likely the blistering will occur.
Whether you use a sprayer or rollers should be decided by the sq. footage involved, but either way you're going to want to use only as much paint as is needed to cover. If you do spray, back brushing will be required and DON'T spray it too thick, or else peeling/blistering is inevitable. And watch out for that crazy SF wind.
Thanks for the advise. We did strip the paint off down to bare wood and took extreme care, as if there was lead. My inclination is to go with prime acrylic latex. Seems that paint formulation change monthly, and latex has had a poor history.
My inclination is to go with prime acrylic latex. Seems that paint formulation change monthly, and latex has had a poor history.
What do you mean by "prime acrylic latex"? Is this different than latex?
Nowadays, all water-based paints are called latex even though there's no actual latex in them at all. I think what you want is 100% acrylic primer. I've used less expensive vinyl-acrylic primers with success also.
-Don
"and latex has had a poor history"
Not sure where that's coming from. Quality water-based exterior paint has been the standard for years now. Of course if your prep is not up to snuff, all bets are off.
I would highly recommend the Zinsser Cover-Stain as the primer. It's oil-based, available in CA, and gives the best base on bare wood - especially something like redwood that might want to bleed through.
I agree that 100% Acrylic Latex has come a long way. But having said that, I just did my bathroom and doors in Benj Moore's gloss oil. I just love the way it lays down nice-n-flat, no brush marks when dry, squeakie clean to the touch and a breeze to clean.
BruceM