Tannin Stain, Painting Company, House Painters, Atlanta, Alpharetta, Sandy Springs, Dunwoody, Brookhaven, Buckhead, Roswell, Marietta, Milton, Decatur

How to Avoid Wood Tannin Bleed from Knots

We completed a project last week that gave us some trouble.  Because this isn’t the first time I’ve seen this problem, I felt that it warranted an article so others can avoid this problem.  The problem is tannin and resin bleeding through knots and “self-priming” stains and paints.

Many of the new paints and stains boast “self-priming” properties.  The selling point is that “it requires fewer coats and products to finish the job so you save time and money.”  While this sounds awesome, it is misleading.

No current product that says “paint and primer in one” or “self-priming” is going to perform as well as separate primers and paints.  For simple applications such as interior painting on previously painted substrates, these products perform fine; but when getting into applications in a more demanding environment, they fall short.

I specifically speaking about wood stains that say “self-priming to prevent tannin bleed.”  My instinct is to ignore these statements and use a stand alone alkyd wood primer or shellac primer on wood, but this time I went just with the stain.  We used package white.  The painters sprayed and back rolled the product per manufacturers’ specifications.  It looked beautiful at first and everyone went home.  When we went back the next morning, every knot on one side of the fence had bled through the stain.

To be fair, this was the side of the fence that had the sun hitting it from first thing in the morning until about 2pm.  This heat causes the tannin and resin to be more active.  However, the data sheet should have said something about this.

I told the home owner I was unhappy with the product’s performance and I wanted to prime and put another coat.  Our client obliged so it time to research.  I have heard horror stories of people applying 3, 4, and 5 coats to still have the knots bleeding through.  I didn’t want to have a story of my own so I got on the phone with technical support.  They told the “self-priming” properties are weak and that it is still advised to prime.

I went with what worked with even the most “knottiest” wood (get the pun? knotty vs. naughty).

Shellac-based primers are the best primers for sealing in stains.  Shellac comes from the lac beetle.  I don’t remember how they beetle makes it, but I am positive that all shellac comes from this little bug.

We see shellac in our everyday lives.  The easiest example is on pills.  The shiny coating on pills or the plastic parts of capsules are examples of “food-grade” shellac.  Now that I provided a visual of what shellac is, it should be simple to see why it is such an effective sealer.

When shellac primers dry, they effectively seal the stain beneath a layer of plastic.

What makes these primers such great sealers is the same thing that makes them ineffective primers for exterior house painting.  Because shellac based coatings create a solid, rigid coating, they are only specified for “spot exterior” application.  This is because of the movement that exterior substrates exhibits due to expansion and contraction from temperature fluctuations.

For this reason, we spot primed the problem knots with an aerosol primer and repainted.  If the bleeding was throughout the wood, we would have opted for an exterior alkyd primer designed for bare wood.

After everything was completed, the fence looked beautiful, our client was happy, and GreenWave Solutions did another good job.  This is why we are consistently rated the best painters in Atlanta.

 

Daniel Macris is the president of GreenWave Solutions for 8 years.  GreenWave Solutions is Atlanta’s First “Green” painting contractor.  We specialized in commercial and residential painting.  We are launching our Atlanta kitchen and bath remodeling division soon!

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Exterior Painting Application Methods

What is the best way to apply paint?

This is another one of those questions that can only be completely answered with the question, “What are you painting?”  In an effort to keep this article from turning into a book, I will answer this question for the homeowner who is getting residential exterior painting.  We will assume that the house is previously painted and the paint is not peeling, cracking or having any other coating failures that will require getting into primers and more advanced painting techniques.  The paint is just oxidized, faded, and it is time to repaint.

Houses are usually constructed from either wood, brick, siding, stucco or a combination of these compounds.  Despite a few exceptions, a high quality exterior acrylic paint will work on any of these substrates provided the existing coating is in good condition.  Paints designed for stucco are thicker and have more elastomeric qualities in order fill hair line cracks and allow for movement.  Some paints designed for wood are self-priming to prevent tannin bleed.

So what is the best way to apply paint to the exterior of your home?

Some painting contractors boast “all work done by hand.”  While this sounds wonderful because of the allure of “handmade” and “handcrafted”, it is not really the best way to have things painted.  Here are the pros and cons of hand brush application of paint:

Pros:

  • No over spray or mess
  • Get into tight areas without having to tapes or cover with plastic or paper
  • No need for respirator or mask
  • Fast, easy clean up

Cons:

  • Slower (higher labor costs or more time painting)
  • Thinner coating of paint (Will wear out and need repainting sooner)
  • Uneven finish (brush marks shows)
  • Manufacturers recommend spraying most coatings

 

The other option for exterior house painting is by using a professional spray machine.  I don’t mean a Wagner paint sprayer you get from Lowe’s for $100.00, I mean a professional Graco, SpeeFlo, or Titan machine that can cost anywhere from $1000.00-$30,000.00.  Spraying paint using the right machine, gun, and tip will render a smoother more even finish than brushing by hand.  In some instances, like painting stucco or applying wood stains, it is necessary to back roll the coating after spraying it on to push the paint into textured surfaces.  Here are the pros and cons of spraying paint (assuming that a skilled professional is using the equipment):

Pros:

  • Thicker layer of paint (lasts longer)
  • Smoother finish and appearance
  • Faster (saves labor costs)

Cons:

  • Creates over spray so protecting eyes, nose, mouth, and property is required
  • Uses more paint due to thicker coating and over spray loss

As a professional painting contractor, I encourage spraying paints whenever possible.  It just renders a better final product.  There are some situations where spraying paint is not feasible due to population, wind, laws, etc.  If you have any questions about painting send the professionals at GreenWave Solutions an email and we will be happy to help you.

 

By:  Daniel Macris

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GreenWave Solutions is the best painting company in Atlanta.  We specialize in interior painting, exterior painting, residential and commercial painting, wall paper removal, deck staining, cabinets and more!  Call us for an estimate.