Popular Woodworking 2002-12 № 131, страница 93

Popular Woodworking 2002-12 № 131, страница 93

Flexner on Finishing

Reducing Brush Marks and Orange Peel

Two of the most common brushing and spraying problems can be avoided with a few simple strategies and a thinner.

Brush marks and orange peel are the flaws created in a finish by the two most common application tools: brushes and spray guns. Unfortunately, there's no way to totally prevent these flaws and still use these tools, but the flaws can be reduced by controlling the viscosity of the finish and by using the tools properly.

Brush marks and orange peel can always be removed after they've occurred, of course, by sanding the hardened surface level (see "Rubbing for a 'Perfect' Finish," August 2001, page 74). But that's a lot of work, and

it can be reduced by keeping the problem to a minimum to begin with.

Brands of the various finishes (varnish, polyurethane, lacquer, water-based finish and so on) differ in how well they flatten out after application, but with any given finish or brand, brush marks and orange peel are worse when the finish is thick or dries fast. Specific to spraying, orange peel can also be made worse by holding the spray gun too close to the work, holding the gun too far away (or moving it too fast), or by not having the gun set right.

The key to determining if you may be creating a problem is to watch the finish in a reflected light while you're applying it. You'll see if the finish is going on smoothly and evenly or if it's brush marking or orange peeling more than you would expect or want.

(I've heard several people say that the way to eliminate brush marking is to use a more expensive brush, but I haven't been able to confirm this. As long as I'm using a decent quality brush - meaning one that costs six dollars or more, has a chisel edge and is made from China or some other good-

Brush marks can be reduced by thinning your finish or slowing the drying time by using a retarder. Buying an expensive brush isn't going to help much.

98 Popular Woodworking December 2002