You may or may not be able to salvage your furniture. It depends upon how badly it’s rusted. In your favor is that rusting problems usually look much worse than they actually are. Rusty water runs down and stains the lower portions, making it appear that they’re rusted, too.
First, use the furniture as you normally would to see if it’s still rigid and strong. Rusted metal has very little strength. Drag your husband away from the sports on TV and have him help you. If a chair is badly rusted, it may collapse when you sit in it. Have him prepared for the worst.
If everything seems sound, take a pair of pliers and gently squeeze on any of the spots that seem rusty. Apply enough pressure to see if any spots are nearly rusted through, but not so much as to crush and damage a good area.
Another, less potentially damaging, method is to hold a magnet against the rusty areas. Rust (iron oxide) isn’t magnetic. If you feel no attraction of the magnet in certain areas, they’re probably too rusted to repair.
Assuming you found some pieces still in repairable condition, the first step is to clean off as much of the rust as possible. Although with the new rust-inhibiting paints, it isn’t necessary to remove every speck of rust, try to remove as much as possible.
Use a large wire brush by hand first. This will remove any of the large loose flakes of rust. Brush hard. You won’t hurt the good steel underneath. Use a smaller (1-inch-long head) stainless steel wire brush in the tight spots. All hardware stores sell these. Use a small file in very tight spots.
If you have access to compressed air, use a sand blaster. A sand-blaster attachment is inexpensive at a store such as Sears and will definitely clean off all of the rust, even in tight spots. Since you’re blasting hard steel, you don’t have to be particularly concerned about damaging the good metal.
People are often intimidated by sand blasting, but don’t be. Do it out in your backyard. Wear safety glasses, gloves, and a breathing mask. The white sand is extremely fine. Every home center store sells bags of sand. Scrub the entire piece with detergent and water when done.
Now with all, or at least most, of the rust removed, it’s time to start the painting process. This is a two-step process: 1) a rust-inhibiting primer, and 2) a protective finish coat of the color of your choice. Oil-based primers seem to work the best. Make sure the paint can has the words “rust inhibitors” on it.
The following companies have very good rust-inhibiting paints: Coronado Paints, BenjaminMoore.com; Fuller O'Brien, MyPerfectColor.com; Rust-Oleum, RustOleum.com; and Sherwin Williams, Sherwin-Williams.com.
As with any paint job, carefully follow the instructions on the paint can. People often forget to pay attention to the recommended temperature range for application. Also, be precise about the length of time between coats of paint, or its effectiveness can be greatly diminished.