Fresh Powder: Waterborne Primers that Sand

Written by on March 3, 2012 in Interior Products, Primers with 24 Comments
sand to powder

Hand sanded with no extraction to demonstrate “powdering” capacity of waterborne primers.

Waterborne Primers

No, we aren’t going to start writing about snowboarding here. This is about the new generation of waterborne primers for wood. These primers are different from their oil based counterparts that most of us have used for decades.

Different in process, that is, but waterborne primers can be used to accelerate through the prep/prime stages and get to spreading paint faster, and get you to a finished product that is near indistinguishable from former systems that started with oil primer.

In most cases, when exploring new primer (or paint) technologies, we are looking for answers to the following questions:

-How does it brush?
-How does it spray?
-How does it dry?
-How does it sand?
-How does it hide?
-How does it adhere to the substrate?
-How does a topcoat adhere to it?

In other words, how does it drive the process in its capacity as the foundation of a finish system.

[Related: To Prime or Not to Prime?]

Our waterborne primer testing is chugging along into the cabinet grade finishing portion of it’s program. So, we thought we would share some preliminary findings on best practices for working with them.

Here are some tips on waterborne primers:

  • Apply liberally, but appropriate to application method
  • Do not overapply
  • Allow for reasonable dry times, determined by drying conditions
  • Sand at about 150 in prep for paint
  • Expect to achieve the same smoothness as with oil, and without punching through

The key to success with waterborne primers is to understand that they dry fast, but are not cured upon drying. You can push the envelope when finishing with a compatible paint base, but knowing the boundaries is completely driven by how and when you sand, which again, is driven by the conditions you provide. In most cases, if you set it up right, you can be sanding within 2-4 hours. This would be mostly out of the question with oils.

For instance, if you are spraying on site and the drying conditions are a “wet” heat source, and you overapply and sand too soon, you will have a miserable experience, just as you would with oil or any other previous generation of primer.

Efficiency

You have to set waterborne primers up for success, and if you do, the results are desirable, and you can move signficantly faster through the finish process than you would with oil primer. Yet another example of how a product becomes profitable. These days, that is what it’s all about. The more I talk with professionals from trades outside of painting, the more I realize that all craftsmen are faced with that same challenge: moving away from (or at least modifying) outdated products and practices, and integrating technologies more conducive to today’s processes and tools.

Read more here about what we and many other pros have to say about flattening out the learning curve to gain the benefit of today’s new waterborne paint systems.

Scott Burt

Scott Burt is a contractor and freelance writer whose column "From the Field" has appeared in American Painting Contractor magazine (www.paintmag.com) since 2008. His writing and projects also appear in other print and digital venues. This site is an extension of Scott's publication work, and he encourages readers to leave comments and questions about articles published here. Hope to hear from you!

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  1. Tom Norman says:

    I’m concerned about one thing:
    How do I get the same incredible results I got 30 years ago on my 100 year old house. How can a water based primer do the same job?

    Here is what I did: I sanded to bare wood, then primed and painted. I have not repainted most of it since then: incredible.

    I painted with an oil-based primer that included linseed oil. It was a product of Brodugan in St. Louis Missouri.

    They later were purchased then by Sherwin-Williams. I talked with Bob Brod about 5 years later. I told him my results with the old standby of linseed oil added primer. He told me they had used linseed oil in their best primers but it had been disconnect discontinued by Sherwin-Williams (probably for cost as I recall.)

    I was told at the time 48 hours for drying oil was important. Because it was drawn into the dry wood and prevented it from cracking.

    Now I have another house and have sanded to bare wood the five to twelve inch 105 year old trim. I’m using ELMERS WOOD FILLER MAX to fill in the cracks and crevices.

    But no where has anyone said anything to me about oil based primer with linseed oil added except negative reviews and 5 ounces max added per gallon if used.

    . So my question is, don’t I have to have oil which soaks into and conditions the wood as it dries, as a conditioning undercoat even as one uses oil on leather boots to condition before putting a top coat? Doesn’t the wood need something to not just seal it but condition and protect its first layer of surface cellulose grain to not just cover it with “plastic like latex” but to seal it to last for years?

    (Linseed oil used to be used in window sash putty and it dried as hard as wood).

    I am nervous that all my work is going to set me up for having to repaint every 7 to ten years.

    30 years ago I sealed with the oil with linsoil added and then applied the latex top coat as I did back 30 years ago?

    My philosophy was to use the best paint possible. How has Latex developed to treat wood better than oil?

    I understand the cost and convenience advantages of fast dry latex primer…and then apply the one coat latex. (FYI:The latex I used was called one coat Super hide top coat.)

    • Scott Burt says:

      Hi Tom, these are great questions. The industry has pretty much shifted in the past 5-10 years. Or, we should say the manufacturers have, which (long story short) has been driven by epa regs. Linseed oil based products went out a while ago and were replaced by synthetic oils – the alkyd era. And even that is quickly being ushered out. All that said, the performance of the old generation oils were a two edged sword. Penetrating the wood was great for protection from the outside in, but caused a lot of failures from the inside out. Because they didn’t breathe, moisture escaping the wall cavities of homes were able to push primer and paint right out of wood from the backside (and of course, no one was backpriming in those days). This resulted in older homes peeling right down to bare wood on pretty large scales. Oils also had a history of becoming brittle and inflexible over time. On the bright side, latex primers are flexible and while they don’t penetrate like oils, the good ones do have extremely good adhesion qualities, and they breathe. I made the switch years ago and have not looked back (and I had used oils all my life). The primary reason that latex has developed to work better than oil is because manufacturers stopped investing R&D funds into oil based products years ago and put those resources into creating latexes that can perform at that level…just in a different way. And you are correct, it is chemistry.

  2. Jayne says:

    Scott, we are first time home owners attempting to take all the proper steps to realize a professional interior paint job of a 100-yr old house. We are perfectionists, and are taking the time to properly sand and prep all walls and woodwork. Sanded woodwork is predominantly painted latex, though there are instances of exposed oil-based and raw wood. At our local SW’s suggestion, we applied the SW Premium Wall and Wood Primer to all walls and woodwork as we were looking for a primer that we could sand to give us the smoothest topcoat finish. Looking closely at our woodwork, we are finding that there are instances where tannins or some other faint yellow stain is bleeding through this primer. It appears that we will need to reprime. This said, what Primer would you recommend that will adhere to the SW Premium Wood and Wall Primer, would you sand the first layer of primer, and can we still use the SW Pro Classic Latex Enamel over the primer that you recommend?

    A second question relates to SW’s 14 day recommendation to paint following application of primer. If we do not paint walls/woodwork within this timeframe, will we need to reprime to get adequate adhesion?

    Thanks for your help, and I have enjoyed reading through your blog.

    • Scott Burt says:

      Hi Jayne, try feathering KILZ Max on the bleeding areas, then scuff it smooth. You can still use the SW paint over it. And no, you would not need to reprime per the 14 day recommendation.

  3. Tim Raleigh says:

    Great article and comments. I gotta get me some ml Campbell Aqualente primer to try.

    • Scott Burt says:

      Hey Tim, hope your year has been good! Let me know if you try the ML. I haven’t used much of any of their stuff but have heard good things from experienced users.

  4. There are a lot of articles about painters and painting. I have to see one cover waterborne painters. A great way to cover the over all process. I can imagine you sand before the paint dries you can have a mess on your hands. Great article Scott.

  5. Great article about waterborne primers. I don’t think I have seen a blog out there really cover this much detail.

  6. Great article about waterborne primers. I don’t think I have seen a blog out there really cover this much detail.

  7. aaron says:

    Thanks Scott.As always,great information.We love working with the waterbornes as much as possible.

  8. Dean Veltman says:

    We have been trying ml Campbell Aqualente primer on some shop work this week. That is some nice sanding stuff.

    • Scott Burt says:

      I have heard that locally as well, Dean. One of the cabinet shops we work with primes with it, and it always comes to us really nice for finishing. They shoot it hvlp and it lays nice. Good to hear. I really am hoping that its a new day for wb primer technology and that mfr’s will continue to embrace it in R&D. At the pro level, we need these technologies, especially in a time when big box forces are working against the concept.

    • Dean there are several MLC products that are must have for doing fine finishes imo. I can’t believe I didn’t know better than to use crystal sealer after sanding with high grit paper for bare mdf profiles.

      @ Scott are you planning on doing some solvent based comparisons? I know acrylics have come a long way, but solvent based primers have continued to change as well. Some for the better others not so much because of voc regs.

      • Scott Burt says:

        Tommy, modifieds only. Advance and any comparables that we dig up. The more we do this, the more I see that oil primers do nothing for efficiency. If we can get consistently within even just 90% of oil performance, its worth the switch. It seems possible to get closer than that though. I know Advance is slow, so we’ll so how the modifieds stack up against straight wb. I know you are concerned about tannin and knot bleed, but for 20 years I have found that the knot always wins in the end. So we probably still bin…thats fast, and it is the standard, but still not a permanent solution, and never has been. Would be nice to think a primer will come along that can solve that. Meanwhile, we push for better grades of lumber on int and ext trim packs.

        • Yea that is the problem I have been seeing Scott. It seems our lumber is progressively getting worse. More fast growth very soft woods, and many high end homes are getting finger jointed trim with dramatic differences in wood grain in a single 20″ stick.

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