A sponge brush is a foam craft brush that often has a wooden handle and a black, flat rectangular piece of sponge on one end. Sponge brushes are handy for many different types of crafts and do-it-yourself projects as they're very versatile. A sponge brush can be used for spreading glue and applying stain, paint or finish. The great thing about them is that they are quite inexpensive and can be disposable. If you can wash them out, they can be used a few more times.
Many crafters use a sponge brush when they don't want to ruin an expensive bristle brush. Sponge brushes make a good alternative to bristle brushes, but they may leave noticeable lines. It’s best to try out a sponge brush for your project first to see what the result will be. You will usually get uniform applications when using sponge brushes.
Although sponge brushes stand up well to most materials, lacquer finish may eat through the foam. Most other types of finishes are usually fine. Again though, a sponge brush also makes a good disposable applicator as it's not very expensive. Sizes of the brush heads vary and even the largest ones aren't usually more than a few dollars. Good quality large bristle brushes, on the other hand, can be quite expensive and if the cheaper ones are used, the bristles tend to stick in the finish — not a desirable quality.
As they are made of foam, sponge brushes usually don't crumble or shred. Sponge brushes are used in decoupage to apply finishes and sealers. For more heavy duty jobs, sponge brushes with thick, plastic handles may be used. Although most sponge brush heads are flat, some are wedge-shaped which may be helpful for pressing down cut-outs and other uses in decoupage projects.
There are also sponge roller brushes available that look like miniature paint rollers. The sponge portions are often yellow in color. Stencil sponge brushes are another type and differ from regular sponge brushes in that they are sort of the shape of a squished marshmallow and are used to daub color inside of stencils.