How to Keep Rust and Splinters From Ruining Your Outdoor Furniture

Water, temperature fluctuations, and sunlight can all damage your outdoor furniture — but luckily, a few simple maintenance practices can restore dried-out wood, bring back colour, prevent water damage, and strengthen the joints of your furniture. You’ll get more life out of your patio, deck, and yard pieces, saving you money even as you make your outdoor spaces more comfortable and inviting. (No one likes sitting down on a chair covered in splinters.)

Use sandpaper to smooth out your surfaces

Sun, heat, and rain can cause fading, greying, and splintering in bare, unfinished wood, but don’t fret — a little sandpaper goes a long way. Start by sanding off any splinters, moving from using coarse- to fine-grade sandpaper and working with the grain of the wood as much as possible to clean up any potential snag spots. You can find “project packs” for sanding at most hardware or home improvement stores that come with a coarse, medium, and fine grit sandpaper included. Each kind of sandpaper will be marked with a number that refer to the distribution and size of the abrasive surface on the paper. Lower numbers (say, 60 or 80) are more coarse, while higher numbers (180 or 220) are more fine.

To choose the appropriate grain of sand paper, examine your piece for large splinters (bigger than, say, the tip of your index finger), medium splinters (about the thickness of your thumbnail), or smaller splinters (that might appear to be fuzzy on your surface). Match your paper to your splinters: If you have large splinters, a coarse sandpaper will work best at first. For medium-sized protrusions, a medium grit sandpaper will work; or anything smaller, a fine grit paper will work best.

Start with a coarse grain to remove larger splinters, and work your way down to smaller grit until you achieve your desired level of surface smoothness. A sanding block is very useful here, and will save you some frustration. Simply wrap your sandpaper around the block to give you added rigidity and save your sore fingers. Sanding blocks are available in hardware stores and are usually made from dense, slightly flexible foam, but in a pinch, you can also use a block of wood or even a dense sponge.

If your surface is relatively new and undamaged, it’s still a good idea to hit it with some sandpaper before applying a protective coating — all the better to shield it before it becomes dried, faded, greyed, or splintery.

Use ferrous sulfate to age your surface for a rustic look

Sanding your piece can also remove a grey, discolored surface, exposing the natural colour of the wood underneath. If your furniture looks a little too new, you can give it a more rustic, greyed look by applying a compound called ferrous sulfate. This non-toxic substance, often sold as a vitamin supplement, will oxidize the surface of your furniture, turning it a natural-looking, weathered grey. Ferrous sulfate often hard to find in stores, but can be easily purchased online.

To apply, dissolve 1.4 ounces (or 2 tablespoons) of ferrous sulfate in one gallon of water, then brush, spray, or wipe it on your furniture with a rag and allow it to dry. To be sure the treatment will achieve the desired result, do a test patch on the underside of your furniture first. A word of warning: Ferrous sulfate works by causing oxidation — also known as rust — so keep it away from exposed metals, including hardware and tools.

Condition and treat your wooden furniture

Once you are done preparing your surface, move on to treating the wood. Most likely if your furniture is bare wood, you’re aiming to keep that look. For natural-looking results that will last, apply an outdoor furniture wax. There are a variety of waxes made for outdoor use, so choose one with a UV protectant as well as waterproofing properties.

To apply your wax, make sure your piece is clean and dry (and that you’ve remembered to read the label on your product for safety information). Also, check the weather report if you’re working outside — rain and high humidity could interfere with your wax’s ability to properly seal the wood surface as it dries.

Once you’ve got a clean, dry, and safe working environment, you can apply your wax to the furniture. Some waxes are meant to be slathered on with a rag while others are intended for use with a plastic putty knife or spatula, so read the label and follow directions. Apply the wax in a smooth, even coat and allow it to dry for about 24 hours.

After a day or so, your wax should begin to feel like it’s hardened, but it will still likely also feel a bit tacky or sticky. To remedy this, buff it with a dry rag or a buffing pad, the same way you might buff a car after waxing it. The buffing should take care of any stickiness and also help smooth out the wax. It can take another few days for the wax to fully cure, depending on the weather, but it shouldn’t need any more help from you. Your furniture will now be splinter-free and protected from sun and rain damage.

A few more tips to maintain outdoor furniture

Check your furniture for loose or rusted hardware and tighten any loose screws with a screwdriver. If it’s a loose bolt, you’ll need an adjustable wrench to do so, and perhaps another to keep the bolt from spinning while you’re tightening it.

For rusted parts, if the damage is minimal, apply a rust remover and use a wire brush and rag to take off most of the discoloured surface. If it’s heavily damaged, better to replace the hardware.

Finally, if you plan to embark on a furniture maintenance adventure, make sure you’re wearing gloves, working outside or in a well-ventilated area, and following all safety information listed on your product’s label. Sprucing up your outdoor space can and should be fun, but inhaling potentially harmful chemicals in a poorly ventilated space is no fun at all.