Latex paint should be well mixed before spraying.
Preparation is critical for a good paint job--and you need to prepare your paint as well as the surfaces to be painted. Don't assume that you can use latex paint straight out of the can. Latex paint needs to be mixed before spraying so impurities don't clog the spray tip, it's the right consistency for smooth spraying and the color stays uniform. Paint sprayers can be finicky machines, so properly mixing, thinning and straining paint before starting work helps ensure a hassle-free job.
Instructions
1. Read the paint label. Some latex paint can and should be thinned by mixing with water or paint conditioner before spraying; other latex paint shouldn't be thinned. Often, the manufacturer will include thinning instructions on the label-use these as your guide.
2. Box all the paint. "Boxing" means mixing every can of paint together. There can be subtle differences in the paint color, even if it was all mixed at the same time. If you have single-gallon cans, pour them into a clean five-gallon bucket and mix them. If you have more than five gallons, use several buckets and pour the paint from one to another until they're well-mixed.
3. Thin the paint according to label directions. If the label gives you no guidance, about one cup of water per gallon is usually sufficient. Mix it well, using a five-gallon paint stir stick (available free at most paint stores.)
4. Thin the paint with latex paint conditioner if you need to slow the drying time (such as in very hot, dry conditions) or to produce a very smooth finish for cabinets or woodwork. Follow label directions--you can add more paint conditioner than water to latex paint without negatively affecting performance.
5. Strain the paint, even if you just poured it from new cans. Latex paint can have specks of grit or dried paint in it, almost invisible but large enough to clog a spray tip. Paint stores carry several types of paint strainers. The most common is a fine-mesh nylon bag that fits over the top of a bucket so you can pour the paint through.