Before spraying any piece of furniture, dismantle large items as much as you can. Remove backs from carcase pieces and remove drawer bottoms, if possible. If you have a complicated project that includes a lot of slats, consider finishing them before final assembly.
How Much Finish to Apply
Novice sprayers often get carried away with the ease of laying down a finish, so they apply too much at once.
You should aim for each coat to be about two thousandths of an inch thick, or in spraying terms, two mils. A mil gauge is a piece of metal with teeth in mil increments. To use the gauge, spray some finish onto an impermeable surface such as laminate or glass. Drag the gauge through the wet finish, keeping it 90 degrees to the surface and pressed down. Withdraw the gauge and note the first tooth that isn’t coated with finish, as well as the one next to it that is coated. Your depth of finish will be an intermediate thickness between these marks. If you have trouble seeing clear finishes on the gauge, sprinkle talc on the wet teeth and blow it off. The talc will stick to the wet teeth.
The Basic Spray Stroke
Lay a flat board or a piece of cardboard on a pair of sawhorses to practice on. Hold the gun perpendicular to the surface, about 6 inches to 8 inches away and about 3 inches off the bottom left-hand corner. Depress the trigger until finish comes out, and move the gun across the board until you get 2 to 3 inches past the far edge. Do not arc your pass; rather, lock your forearm so that the gun moves across the board at a constant height and in a straight line. As you make another pass, overlap the first by 50 percent to 75 percent. Move the gun fast enough to avoid puddles of finish, but not so fast that the surface feels rough when it has dried.
I start with the surface closest to me and work toward the exhaust fan in my spray booth to reduce overspray landing on the wet finish and leaving it rough. Practice this basic “stroke” until it becomes second nature, because it is fundamental to all spraying.
The basic spray technique for flat surfaces is called a crosshatch. Begin with the underside of the piece. At a 90 degree angle to the grain, start your first pass at the edge closest to you and spray a series of overlapping strokes. Then rotate the top 90 degrees (it helps to have it on a turntable) and spray with the grain.
Holding the still-dry edges, turn over the panel and place it back on the nail board. Spray the edges with the gun parallel to the surface, then bring the gun up to 45 degrees to the top and spray the edges again to get extra finish on them. Finally, repeat the cross-hatching on the top side.
If you get a drip, and you won’t be damaging a delicate toner or glaze underneath, wipe the drip immediately with your finger and lightly re-spray the area.