Blue Door Painters describes three important terms in coatings technology.
Effectively painting a wall requires designing a chemical which changes from a liquid to a solid in a very precisely choreographed manner. If it changes too soon, the coating on the wall will be chunky, rather than smooth. In addition to looking unattractive, a chunky coating will not be likely to be continuous, and the gaps and breaks in the layer will cause the paint to fail. On the other hand, a substance that is too runny, and stays in liquid form too long, will run and sag before it hardens, once again creating an unattractive and discontinuous coating that is prone to failure. Chemists and paint artisans have struggled for years to come up with the perfect chemical mixtures that magically transform from smooth, continuous liquid to solid, sturdy solid at the right time and in the right way. To do so, scientists had to continuously tweak the viscosity, flow, and leveling of their concoctions.
When you are shopping for paint today, you will find products on the market that still possess a range of properties as far as their state of matter is concerned. Understanding viscosity, flow, and leveling will help you select the right paint for your job, and will allow you to notice when your paint is not performing as it should.
Viscosity is the paint’s resistance to flow – simply put, how ‘heavy’, ‘thick’, or ‘sticky’ it is. If paint is runny, it has low viscosity, while if it is tacky and thick, it has high viscosity. Ideally, right out of the can paint should have the viscosity of a warm maple syrup – runny, but not as runny as water, and with enough thickness to create a slight relief when applied to a surface thickly. The desired paint viscosity (and the paint performance in general) will vary greatly based on the temperature. At high temperatures, the viscosity is always lowered, and therefore a higher-viscosity paint is desired to compensate. The opposite is true for cold temperatures. In the Washington DC / Northern Virginia area, where the seasons are so variable, attention needs to be payed to the timing of when the project is undertaken to determine what viscosity should be aimed for.
Flow involves both the viscosity of the paint, but it also involves the surface tension. The surface tension tends to vary according to the viscosity (lower viscosity has more flow and lower surface tension); but this is not a direct correlation. Various additives can change the chemistry of the paint to create the desired flow even with variation in the viscosity.
When the flow if the paint is not ideal, the coating will demonstrate failure patterns such as running, sagging, chunking, or cratering. While improper application (and insufficient prep) can also cause these problems, if they happen in your coating, the first thing you should do is check your paint can and contact the manufacturer to make sure that the paint is performing as it ought to.
Finally, the leveling of there paint describes how flat of a surface it can make. Good leveling requires ideal viscosity and flow, but it also relies on chemical complexities in the paint to neutralize common issues like fisheyes, craters, blistering, alligatoring, streaking, and other problems that come from a coating that is not perfectly smooth. Since there will never be a perfectly flat substrate, nor a perfectly ideal administration, the paint will always have to correct for these imperfections with its chemistry. Paints like Sherwin Williams’ Duration excel at creating smooth, level coatings out of less than ideal conditions.
If you are thinking of painting your home and you want further advice on paint or painting technology, or you are looking for either a free estimate or further product recommendations feel free to contact us!