The ingredients that go into the paint we get from store shelves has changed significantly over the last decade. The additives, precursors, and substances used to make paint have been heavily restricted due to regulations from the Environmental Protection Agency. The Toxic Substance Control Act, and the Clean Air Act restrict several additives that have been traditionally used to enhance the properties of paint. Ethylene Glycol, for example, is a substance used to lower the freezing point of the paint and act as plasticizers, added to increase the paint's flexibility. When regulations prevent or limit the use of these substances, the quality of the paint suffers.
Seasoned painters have taken notice of the absence of these additives. Most notable are the clumps, chips, or skins present even in newly purchased paint. These unwelcome side effects of regulations create a headache for painters. Instead of popping the lid off a can or bucket of new paint and going straight to work, painters are stuck wasting time and money straining clumps from their paint before starting the job. So unless you are willing to get your paint from the underground black paint market, you're stuck with the frustration, and inferior quality these restrictions cause.
Unfortunately it's not just the new ingredients in paint causing them to clump and chip. The life-cycle of a can of paint is filled with temperature changes, long periods of sitting on shelves, and jarring motions from transport and mixing. Paint is manufactured in large factories, transported in hot, or cold trucks depending on the season, stored in warehouses for long periods of time, transported to retail locations, and put on shelves until the customer picks it up from the store. As can be expected, the temperature fluctuations the paint experiences throughout this process can be extreme, especially in the colder or hotter months. Just like the syrup for your pancakes that gets too thick to pour when it sits in the refrigerator, paint gets thick when cold and watery when it's hot. When these fluctuations happen, you end up with clumps in your paint that need to be strained out before it can be used effectively.
When paint sits on shelves in warehouses or distribution centers for extended periods of time, a small amount dries out on the lid or higher up on the walls of cans or buckets. When color is added at the store, the can is shaken vigorously, and the dry portions flake off and end up creating chips throughout the paint. These chips can end up on your walls if they aren't property removed before the paint is applied.
Several solutions exist to remedy the issues caused by all of these factors, but many of these methods create entirely new problems. Veteran painters likely remember using a pair of nylons to strain the clumps and chunks from their paint. Consequently this has led to many angry wives who aren't thrilled with the prospect of wearing a pair of paint encrusted pantyhose to church the following weekend. Other solutions include mesh bag strainers, cardboard straining cones, and even using kitchen equipment like deep fryer oil strainers. Unfortunately bag strainers make a huge mess and absorb paint, cardboard cones overflow and disintegrate, and oil strainers are bulky and tend to deform when dropped or stepped on.
With all of these issues just to get a clean coat of paint on the wall, it's no wonder painters have been left searching for an easy solution.