Woodworkers often refer to wood putty as wood filler, wood patch, or plastic wood, and each name is appropriately descriptive. Woodworkers use putty to fill imperfections in wood. It is a glue-based mixed with filler, such as sawdust or gypsum. When a manufacturer refers to putty as water-based, solvent-based, or oil-based, it means that the glue base is one of these types.
Traditionally, wood putty has been oil-based or solvent-based. Solvent-based putties generally have strong fumes and need chemicals, such as lacquer thinner or acetone, for clean-up. Typically, these putties have a wider variety of colors available to the novice woodworker.
Water-based putty has several advantages over oil-based and solvent-based putties. It usually is free from heavy fumes and is easy to clean up with water. Water will remove any wet product, but once the putty has set, water will not remove it. Water-based putty is the most environmentally friendly.
Oil-based putty is a slow-drying putty that stays flexible longer than the other types. Usually, builders use it to fill nail holes in woodwork. A person can blend two or more of the colors together to customize the color to match the wood stain. A woodworker may clean up oil-based putty with oil solvents, such as turpentine.
One of the other types of wood putty is nitrocellulose-based putty, which dries quickly but needs lacquer thinner or acetone for clean-up. Gypsum-based putty comes in a powdered form, and the user mixes it with water to make a usable product. One advantage of gypsum putty is that it stores well. Acrylic putty is a water-based product, and water will clean up a wet product but not dried putty.
Another product that is similar to putty is wood dough. Wood dough is a patching substance that comes in a variety of colors. Some woodworkers and manufacturers classify it as a separate product because some putty remains soft. Wood dough usually hardens as it cures, and woodworkers sand it afterward. Other manufacturers do not have a separate classification and label all products as wood putty.
Typically, good filler will not shrink or pop out and sands smoothly when set. Many woodworkers use putty to even out the grain in certain woods that have open pores or large pores. Some examples are walnut, hickory, and oak wood. Wood putty allows a woodworker to overcome the various problems that these woods present to the craftsman. When choosing putty, a person needs to consider the purpose.
Different types of putty have their strengths and weaknesses. For example, when choosing putty for outdoor furniture in areas that experience temperature extremes, woodworkers often choose solvent-based putty. Water-based putty may freeze or pop out.
Some people make their own wood putty by mixing wood glue and sawdust. Often a person will use the sawdust from a project so that the putty will be a close match. One of the major disadvantages of this is that the product is not as strong and durable as commercial products.