Quality control can be a challenge for many spray operations, given the vast number of variables in industrial finishes, your paint or coatings system, and the different end uses for your customers. It also can be overwhelming, with multiple tests or approaches to color, film thickness, adhesion, and resistance to scratching, gouging, and impact. Some applications warrant testing for weather resistance (moisture or sunlight) or corrosion. It’s a lot to manage, but there is a lot at stake for your business if you are vulnerable to corrosion and quality issues.
Kyle Pavlik and Kevin Terry of Midwest Industrial Coatings, Inc., gave a presentation about the importance of testing and verification at Spray Equipment & Service Center’s Tech Days. Among their takeaways:
A disciplined testing and verification program can save you from a lot of headaches.
It can drive impactful changes in your operation by predicting performance (or lack of performance) prior to full scale application.
It can provide peace of mind to customers and arm prospects with confidence.
Spray Equipment & Service Center can work with you and help connect you with resources to develop a custom testing and verification program. They can help you address key concerns, such as: Is your finish high enough quality for a product that may be exposed to thousands of hours in harsh elements? It’s better to know than risk a loss of business if it is not.
Let’s look at some considerations for testing.
Daily Testing: Focus on Viscosity and Thickness
Viscosity and thickness are the foundation of any paint. Simply put, you are testing them daily to account for the many variables in your application process and different needs for the finish. You are measuring the viscosity of liquid coatings for proper atomization. You are measuring thickness with the end use in mind – the coatings for a bridge might be 10 mils, agricultural equipment may call for 2-5 mils, and some fine finishes are less than 2 mils thick.
Viscosity
Solvent and water-based paint operations need to be tested daily as viscosity can change. Even barrels of paint with an agitator are not perfectly sealed, which means you may need to add liquid to account for evaporation loss. Changes in water-based paints could be indicators of stability issues or potential microbial growth, especially if the viscosity is getting thinner. In addition to bringing the paint back to its original viscosity, you will want to do a root cause analysis. If the issue is microbial or a fungal contamination, you will be battling it every day until it is resolved.
Film Thickness, Cure, Hardness
You can measure film thickness before the material is dry or after curing. This can be done manually or with gauges. Most gauges measure the total thickness of the coating, though there are high-end gauges that read separate layers of material. Manual testing to determine if a coating is fully cured includes MEK Double Rubs. Pencil Hardness is another technique to measure resistance to scratching or gouging.
Crosshatch Adhesion
We suggest testing daily for adhesion, as how a coating sticks to a substrate is a core attribute. But many people have tested on a daily basis, and with little or no evidence of variance, they have gone to weekly or less frequent testing. Testing varies with different approaches for coatings less than 2.0 mils thick, from 2-5 mils, and for over 5 mils thick.
Color
Color has quantifiable characteristics that can be measured with handheld devices, such as a portable spectrophotometer. But testing can be done by human eyesight if you have a consistent light source to compare color from run-to-run or day-to-day. Color is an attribute that carries a different level of importance for retail products vs. industrial. For example, a boat or ATV manufacturer is probably going to do daily testing for color, gloss and waviness (known as orange peel). An agriculture equipment maker may be more concerned with corrosion than appearance and test less frequently.
Surface Profile
If you have a blasting operation, you should do daily surface profile testing to measure the peak-to-valley depth on the steel surface area. This depth is the anchor for the applied coating. Daily testing provides assurance that you have the necessary depth for your desired performance. There are a variety of tools for testing a surface profile.
Weekly Testing: Check Your Paint Booth’s Air Flow and Pressure
For many operations, you’ll want to test air flow in your spray booth operation on a weekly basis, as improper air flow will lead to defects in coating appearance. If the filters are clogged, typically the first thing you would notice is an increase in overspray.
Many spray booths have a manometer that measures air pressure on each side of the filter wall. The manometer displays the difference in air pressure, which indicates when the filter is clogging and needs to be replaced.
You can also use a velometer for booth testing. It takes a direct measure of the speed of the air flow, which is important for safety reasons and to ensure you reduce the possibilities for overspray.
Monthly Testing: Monitor Changes in Operations and Seasonal Differences
Seasonal changes also can impact your paint system settings as building temperatures vary. It’s not unusual for the temperature in a facility to be in the low 60s in the winter but close to 80 degrees in the summer. That impacts intake air for ovens as well as other equipment.
Implementing new coating technology requires more frequent testing, but once a new process is in place, maintenance programs often call for a monthly check. Likewise, making a significant adjustment in your operation also warrants regular reviews.
Lab Testing: Conduct Verification and Evaluate Business Options
While some OEMs have lab-quality testing equipment, most industrial entities rely on their paint and coating suppliers to perform sophisticated testing. Lab testing is a great approach for annual verification. Many companies do tests on a quarterly basis, which provides more historical data, and it also can identify quality issues as they evolve.
Lab testing is also a good choice when building a case for moving up a step or two for higher performance. If you are considering a higher quality 2K urethane, you can test it out for impact. Likewise, if you are trying to save money by going a notch down in corrosion protection, you’ll want to be sure the finish is still high enough quality to meet customer’s expectations.
Work With Spray Equipment & Service Center for Your Testing Needs
There are many simple quality control tests that provide assurance that your spray operation is performing as desired. Digital testing tools are improving in quality, and many are coming down in price. But tools for sophisticated testing can still be cost-prohibitive, so many operators rely on their paint suppliers for some areas. Experts at Spray Equipment & Service Center can work with you across the spectrum of testing and verification. We also provide qualified technical support and added value through:
ADVICE: Our experience, expertise, and approach work for you at every stage of your business.
SUPPLY: We have the right equipment and parts in stock when you need them.
SERVICE: We are just a phone call away (866-953-0526).
