Do It Yourself: A primer on primers: You must know 3
Q. I want to do a lot of painting of outside woodwork, including wood garage doors, entrance doors to my house, trim and so forth. I have a top-quality latex paint in mind. However, I am confused by the many primers available. How do I know which ones to use?
A. Most painters will never need to use more than two or three types of primers. In fact, you can even buy self-priming paint these days, though it is still somewhat controversial and I am personally sticking with primers and regular paint.
Also, sometimes no primer is needed when re-painting with regular paint, such as when the existing paint is clean, sticking well to the surface, and is not glossy. In these cases, the sound existing paint will serve as the primer.
However, a primer is needed when there is bare wood, when the existing paint is chalking (powdering) and can’t be thoroughly cleaned, or when there are stains that can’t be removed by cleaning, knots or other contaminants that will “bleed through” the new paint.
So the three types of primers you should know about are oil based, water based and stain killers.
Even though most pro painters now use water-based or latex paint, many prefer to use oil-based primers because they are considered better at priming weathered bare wood, chalky existing paint, and for blocking potential stain problems such as knotty wood and nail heads.
Latex primers are the favorite with those who want fast drying; they can be re-coated sooner than most oil primers. With latex primers, tools can also be cleaned up with soap and water, while oil-based primer cleanup is with mineral spirits.
Even the choice between oil-based and water-based primers has been simplified with Zinsser’s Smart Prime, a water-based primer that is said to have the advantages of oil.
Stain-blocking primers are a special category that might be needed only occasionally, such as in sealing knots or water stains that can’t be sealed with oil-based primer. B-I-N, a shellac-based stain blocker and another Zinsser product, is a good choice for difficult stains.
Q. My lawn has good-looking grass, but there are ugly patches of dandelions that I would like to get rid of. I’d rather not spread chemical weed killers over the entire lawn. How can I destroy just the dandelions?
A. Probably the simplest approach is to use a spray-on weed-killer like Weed-B-Gon and spot control the dandelions. That means spraying each dandelion individually with the herbicide. Herbicides like these usually come in gallon containers with a pump sprayer attached.
If you have a lot of dandelions, though, using the small pump sprayer can be tiresome, and a better approach is to buy a good garden-type sprayer that uses compressed air to dispense the liquid. Pour the herbicide into the sprayer, pump it up, and hit each weed with little effort.
Spring isn’t the best time to kill dandelions, however, so some will probably reappear by fall, when another spraying should clear out many of them.
Be careful choosing your herbicide, since some, like Roundup, will kill grass as well as weeds and you might end with a lawn full of bare spots. This is the case even with white vinegar, which if used full strength is an excellent weed-grass killer.
If you don’t want to use any kind of chemical spray, you can try hand picking. It won’t help to just pull off the top- of the plant; you must get the entire root. For this you need a weed-digging tool, which you can find at most garden centers. The tool resembles a long screwdriver with a forked end; force it deep into the ground alongside the dandelion root, wiggle it until the root is loose, then pull out the entire plant, root and all.
You can help prevent the spread of dandelions by nipping off the yellow blooms before they go to seed.