How to maintain and refinish an old porch swing
If your porch swing has been hanging around for years it's time you checked it over for signs of fatigue that could spell danger. If you've come across an old porch swing at a yard sale or found one hidden in your grandpa's garage, consider this before hanging it up and trusting it with all your weight: is it safe?
A good start would be to scrutinize the integrity of the wood. Look for signs of rotting wood, cracks, or splintering slats. In most cases trouble spots can be repaired or re-enforced. If a back slat or seat slat is broken, cracked, or otherwise weakened, a woodworker can help you manufacture a matching piece to swap it with. Also, check the back, arms, and seat areas for splinters. Thoroughly sand these surfaces down until they are smooth and splinter free.
The bare wood of the new or sanded parts of the swing will need to be touched up and protected with paint, or stain and varnish. If the entire swing is looking dull and weather worn, you may want to paint or stain the entire piece of furniture. For a painted swing, use two coats of exterior paint. When staining is preferred, rub the stain into the bare wood, let it dry, and then apply several coats of varnish or polyurethane. After each application, allow time for drying, and lightly sand between coats. The more coats of varnish applied the smoother and more weather resistant your finish will be.
After the wooden structure of your porch swing is made sound, inspect all of the hardware on the swing, the chains it will hang from, and the hardware holding it to the ceiling. Replace all questionable and rusty hardware: bolts, nuts, and chains, before hanging your swing.
To replace old, rusty chains, pry open the "S" hooks. Remove old chains and replace both the chain and the "S" hooks with new ones. Then for safety sake, squeeze the "S" hooks closed with pliers. Now it's time to hang the swing.
The safest way to hang a porch swing is with eye bolts, but this is only possible if you have a clearing above the beam you are securing the swing to. If this is the case, drill through the beam, insert a bolt upwards, making sure it is long enough to clear the beam, then slip on a lock washer and fasten it with a nut. When there is no access to a clearance above the beam, use lag screws with an eye. These can be purchased at your hardware store in various sizes. Bolt and screw sizes correlate to pounds of pressure they can hold; plan on 500 pounds for a porch swing that seats two. Your local hardware store personnel will be able to help you choose the correct size eye bolts or lag bolts.
Install your lag screws with eye, or eye bolts, and test them with your own weight. If you are a "light weight" find a heavier friend to grip the eye bolts and pull on them, one at a time, with all of his weight. If there is absolutely no give or wiggle to the bolts you're all set.
Use open "S" hooks or spring snap links to connect the chains of the swing to the eye bolts, or to the eye of the lag bolts, on the ceiling. It's not necessary to squeeze the overhead "S" hooks closed. If they are left open it is easier to remove the swing for storage over the winter, or to hike the swing up and fasten it near the ceiling for protection from weather during the winter months.
As for maintenance, check your porch swing over a couple of times a year. Inspect the hardware to make sure nothing is working its way loose. If your swing develops a rhythmic squeaking from the chain connections, that problem can easily be taken care of with a few drops of lubricant. That's it; now you just sit a spell and enjoy your porch swing.