Spray finish wood: 8 important tips and techniques

Off-the-shelf aerosol cans of shellac, lacquer and polyurethane allow you to quickly apply a finish that's free of brush marks. Spraying is also an efficient way to apply finish to complex shapes. Here are eight important tips and techniques to help you get the best results.

• Spraying is fast and gives a smooth finish, but it also creates a fine mist of solvent and finish that drifts and settles on everything in sight.
• This mist is dangerous to breathe.
• To avoid problems, apply these sprays outdoors if possible.
• If you spray indoors, cover everything with plastic sheeting or drop cloths and wear a respirator fitted with organic vapour filters, especially if you're spraying lacquer.
• Also put an exhaust fan in the window.
• Read the label on your spray can for additional safety precautions.

• It's hard to get even coverage if you start and stop while spray the surface you're coating.
• The spatters that happen when you first push the button can blemish your work, and spray builds up in one spot if you don't move fast enough.
• To avoid these problems start spraying before you reach the edge of the project, move across the project at an even pace, and stop spraying after you've gone past the far edge.

• It's natural to swing the spray can in an arc, but this results in uneven coverage.
• When you spray with an arcing motion, your finish will build up in the centre and be light on the edges.

• Focus on keeping the spray tip an equal distance from the surface as you move it along.
• At the same time, keep the can moving at a steady pace to get an even coat.
• The key to great spray finishing is to apply just enough finish to wet the surface without creating runs.
• Luckily, you can prevent runs if you apply several thin coats rather than one or two thick coats.
• The finish may look blotchy after the first coat, but additional coats will produce a uniform finish.

• To get even coverage, overlap the spray about halfway onto the previously sprayed section.
• If you just overlap the edges, you'll get a narrow band of thicker finish where the two strips meet.

• A spray-can trigger handle saves your finger and gives you better control of the spray.
• You can find spray-can trigger handles at home centres and hardware stores.

• Spraying a heavy coat of finish over a dark stain or over some oily exotic woods can ruin your project's appearance.
• The solvent in the finish can dissolve the stain or the colour in the wood and cause it to bleed or get muddy looking.
• To avoid this, prime these types of projects with several thin mist coats before applying a thicker coat of finish.
• To apply a mist coat, keep the can higher than normal from the surface and move the can faster than usual.

• When you have a small project with many sides to spray, placing it on a turntable will speed up your job and make it easier to get good results.
• Instead of trying to move around the project as you spray, just give the turntable a little spin.
• To create a makeshift turntable, mount the hardware from a lazy Susan to a scrap of particleboard or plywood.
• Then mount a plywood or particleboard disc to the hardware for your platform.

Keep these eight important tips and techniques in mind to help you get the best possible results from your spray finish.