Controlling Gloss in Wood Coatings

I took my camera with me on my trip to Victoria and Vancouver, B.C. this week. During a quiet moment, I found some great pictures on my memory card that I had forgotten were there. One of those that inspired me anew this week is included here. I took it at IWF 2012 in Atlanta in August.

On one of my strolls through the aisles at IWF, I came across something that previously I had only heard about; a gloss meter.

I know. Seeing a gloss meter may not be something on your bucket list. But as a wood coatings guy, I spend a lot of time explaining and dealing with gloss. Gloss is a big deal in my circle. You also know that I love tools. Remember, I’m “Tool Time Bernie.” I was so excited that I took pictures of this device. I was surprised to find that it was about the size of a 6” sub sandwich.

There was a company exhibiting in Atlanta that was demonstrating their ability to adjust gloss in flat line applied coatings. Their machinery was set up in their booth. They were running samples through the machine. To validate their results, they had a digital gloss meter to quantify what they had accomplished.

click image to zoom Here’s what I knew going in the door that day. I knew that gloss was measured with a gloss meter. I knew that the process involved shining a light on the coating at a specific angle and then measuring the intensity of the reflection from that light. Obviously, the more light that is reflected, the more glossy the coating. In clear coatings, where reflections can come from within the coating itself, the unit of measure for the reflection is given in terms of the percent of light that returns to the gloss meter.

Also referred to as sheen, there are no strict standards across the industry. However, there are some general ranges that can be referred to. A dull sheen is usually around 15% reflection. Satin is around 35%. Semi-gloss is approximately 65% and gloss is usually 80% and higher. Of course, within the opaque coatings it is not unusual to see different sheen names including eggshell, flat, and wet look. The latex paint on the walls of my house is considered a satin eggshell sheen.

Let’s jump ahead to the next issue. That would be how we manipulate gloss or sheen in a coating. There are pastes and powders available to modify sheen levels. The pastes are the easiest to use because they are already pre-liquefied. If you’ve ever tried to evenly disperse a dry powder in a liquid, you can appreciate the tendencies for clumping which can be problematic. The significant ingredient in these flattening pastes is silicon dioxide otherwise known as silica.