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The Environmental Irony: How Improper Equipment Can Sabotage Low VOC Benefit

Introduction

As the bathtub, tile, and countertop refinishing industry evolves, so do the products and tools professionals use. One of the most significant changes in recent years has been the shift towards low VOC (Volatile Organic Compounds) coatings due to stringent environmental regulations. While these products offer environmental benefits, they also present new challenges, particularly in how they interact with spray equipment like turbine HVLP (High Volume Low Pressure) sprayers. Understanding the relationship between low VOC coatings, their viscosity, and the capabilities of spray equipment is crucial for refinishing professionals to achieve optimal results without compromising the integrity of the coatings.

Understanding VOCs and Their Impact

What are VOCs?

VOCs are chemicals that evaporate at room temperature and contribute to air pollution. In the context of coatings, VOCs are primarily found in the solvents used to thin the paint or coating for application. Low solid, high VOC coatings contain more solvents, which evaporate into the atmosphere, contributing to pollution.

Transition to Low VOC Coatings

Historically, coatings used in the refinishing industry had solid contents ranging from 35% to 45%. This meant that up to 65% of the product was liquid solvent, which would evaporate during drying, releasing VOCs into the environment. This means low solid coatings are not environmentally friendly. With the push towards greener practices, many states have mandated the use of low VOC coatings, which contain higher solid content—typically between 72% and 87%—and less solvent. The result is less evaporation and a reduced environmental impact.

The Relationship Between Viscosity and VOC Content

High Solid, Low VOC Coatings

With low VOC coatings, the reduced solvent content results in a higher concentration of solids. This makes the coating thicker or more viscous. Viscosity refers to the thickness or resistance to flow in a liquid. High viscosity in coatings can make them more challenging to spray, especially with equipment not designed to handle such thick materials.

Low Solid, High VOC Coatings

In contrast, coatings with higher VOC content have more solvent, making them thinner and easier to spray. This lower viscosity means that older or less powerful equipment, like 2- or 3-stage turbine HVLP sprayers, can atomize the coating more effectively.

Spray Equipment: The Evolution of Turbine HVLP Sprayers

Turbine HVLP sprayers are popular in the refinishing industry due to their efficiency in applying coatings with minimal overspray and waste. These sprayers use air generated by a turbine to atomize the paint. The number of stages in a turbine refers to the number of fans in the turbine, with each stage increasing the pressure and air volume.

Why 2-3-4 Stage Turbines Fall Short

When using high solid, low VOC coatings, the increased viscosity means that more pressure and airflow are required to atomize the paint properly. A 2- or 3-stage turbine, which might have been sufficient for lower viscosity, low solid, high VOC coatings, lacks the necessary power. The result is a coating that does not atomize correctly, leading to poor finish quality.

The Irony of Unintentionally Compromising Your Green Marketing: The Common Mistake

One of the most ironic and counterproductive practices seen in the bathtub, tile, and countertop industry is the adding of solvents to the low VOC coating mix to make them easier to spray with underpowered equipment.

The Pitfall of Compensating with Reducers

Simply adding a reducer to control the viscosity to compensate for using an underpowered turbine HVLP sprayer is not the solution. This approach may temporarily address spray-ability issues, but it fundamentally compromises the coating's integrity. Over-reducing can diminish the coating's solid content, leading to reduced durability, gloss, and overall performance. Moreover, increasing the solvent content also raises the VOC emissions, undermining the environmental benefits of low VOC coatings. The proper solution is to use the right spray equipment capable of effectively atomizing high solids, low VOC coatings without the need for excessive thinning.

So, How Much Solvent is Too Much?

The coating as it is sold and received by the refinisher is already low VOC, typically containing fewer than 50 grams per liter (g/L) for flat paints and under 100 g/L for non-flat paints. Adding solvent to make it sprayable with underpowered turbine HVLP sprayers increases the VOCs, potentially pushing it out of low VOC compliance. So, how much is too much?

Let’s break down a few examples:

• Base Mix: 12 ounces of Part A and 3 ounces of Part B, totaling 15 ounces.
• Adding 3 Ounces of Reducer:
  • Total Mix: 18 ounces.
  • Percentage of Reducer Added: 3/15 = 20%.
  • Original Solid Content (82%): 12.3 ounces solids.
  • The Reduced Solid Content You are Spraying: 12.3/18 = 68.3%. (No Longer VOC Compliant)
• Adding 4 Ounces of Reducer:
  • Total Mix: 19 ounces.
  • Percentage of Reducer Added: 4/15 = 26.7%.
  • Original Solid Content (82%): 12.3 ounces solids.
  • The Reduced Solid Content You are Spraying: 12.3/19 = 64.7%. (No Longer VOC Compliant)
• Adding 5 Ounces of Reducer:
  • Total Mix: 20 ounces.
  • Percentage of Reducer Added: 5/15 = 33.3%.
  • Original Solid Content (82%): 12.3 ounces solids.
  • The Reduced Solid Content You are Spraying: 12.3/20 = 61.5%. (No Longer VOC Compliant)
• Adding 6 Ounces of Reducer:
  • Total Mix: 21 ounces.
  • Percentage of Reducer Added: 6/15 = 40%.
  • Original Solid Content (82%): 12.3 ounces solids.
  • The Reduced Solid Content You are Spraying: 12.3/21 = 58.6%. (No Longer VOC Compliant)

The Benefits of Using Powerful Turbines

Investing in a more powerful turbine, like a 5- or 6-stage model, will not only help you maintain the integrity of low VOC coatings but also deliver a significantly better final product. By avoiding the need to add excessive reducers, you'll achieve a higher mil thickness and a more even application without the issues that come with uneven or excessive solvent evaporation, such as pinholes, bubbles, blushing, and loss of gloss.

Conclusion

The relationship between low VOC coatings, their viscosity, and turbine HVLP sprayers is complex but critical to understand. As the bathtub, tile, and countertop refinishing industry continues to evolve towards greener practices, it’s essential for professionals to invest in the right equipment—like 5- or 6-stage turbines—to ensure that they can apply these coatings effectively without compromising on quality or environmental benefits.

And remember, while it might seem like adding a little extra solvent is just a way to make life easier, it’s a slippery slope. Before you know it, you’ve turned your eco-friendly coating into a VOC soup that not only breaks the rules but also performs like a soggy pancake. So, resist the temptation to take shortcuts—because just like in cooking, too much sauce can ruin the dish!

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