QI recently bought an airless paint spryer that cost about $300. I need to paint just about every room in a large house and also do the exterior. Some friends have told me it is a bad idea to use a sprayer. I haven't used the tool yet and can still get my money back. What do you think? Any advice on using a sprayer? -- F. Faerber

APaint sprayers appeal to many do-it-yourselfers, who feel sprayers can make painting large surfaces easy and fast. This might be true for experienced painters, but a sprayer in the hands of an inexperienced user can be tricky and messy. Most do-it-yourselfers buy airless sprayers, which use a built-in motor to propel the paint instead of compressed air. These can be especially difficult to use.

Here are some points that might help you make up your mind about sprayers:

* Paint consistency. Sprayers work best with paint that is a certain consistency. The popular latex paints that most do-it-yourselfers prefer are generally too thick and must be thinned carefully. If the paint is too thick, it will spatter or clog the sprayer. If it is too thin, the paint will drip and run on vertical surfaces.

* Overspray. Airless sprayers tend to expel clouds of tiny droplets of paint that don't land on the target surface. Nearby surfaces that are not supposed to be painted must be carefully masked or covered, often a time-consuming process.

* Painting technique. Spraying an even film of paint takes skill, practice and patience. Before painting anything valuable, it pays to practice on cardboard, plywood or some scraps. The owner's manual should have tips on technique -- study them carefully.

* Respiratory protection. Because of the dispersal of the paint into fine droplets that can be breathed into the lungs, it is important to wear protective filters over the nose and mouth. This is especially important when using paints or finishes containing strong (and sometimes toxic) solvents.

* Skin protection. Paint is often propelled from airless sprayers with such force that it can actually penetrate the skin and cause injury. Wear goggles, gloves and other protective clothing, and be careful where you aim the sprayer.

* Cleaning. After every use, all spray equipment must be thoroughly cleaned. This can be a lot more difficult and time-consuming than cleaning a paint brush or tossing out a used paint roller.

I think sprayers are fine for some jobs. For example, if you want to paint lawn furniture or cabinets that can be taken outside, spraying works well. Spread a big piece of plastic, place the object to be painted on the plastic, and blast away. A sprayer is also fine for painting a fence or outside surface where overspray isn't a problem. There is also a type of sprayer, called HVLP (high volume, low pressure), that is much easier to control than an airless sprayer and minimizes overspray problems.

For typical do-it-yourself painting, including interior rooms and woodwork or the outside of a house, I recommend traditional tools, such as brushes, paint rollers and paint pads.

I have a screened-in porch with aluminum screens. A hard white substance collects in the tiny holes in the screens. Can this be repaired or must I replace the screens? -- F. Allen

Unpainted aluminum screens are subject to corrosion of this type. Try cleaning the screens in place with a brush attachment on a vacuum cleaner. If this doesn't work, take the screens down, lay them flat on the lawn, and go over them with a scrub brush and a solution of one-half cup laundry detergent to a gallon of warm water. Scrub both sides. After scrubbing, rinse the screens with a strong stream of water from a hose.

If you replace the screens, you might choose vinyl screening, which won't corrode.

We recently bought a house and would like to convert the basement into living space. Where do we start? -- K. Burt

A good start would be to obtain and study one or more books on basement remodeling. This is a complex project that often includes refinishing walls, the floor and the ceiling. It can also include upgrading insulation or installing new wiring and plumbing. The basement should also be dry -- not subject to flooding. One good book on the subject is "Basements: Quick Guide" (Mark Feirer, Creative Homeowner Press, 1995).

Questions and comments should be sent to Gene Austin, 1730 Blue Bell Pike, Blue Bell, Pa. 19422. Send e-mail to doit861@aol.com. Questions cannot be answered personally.