Types of Putty Knifes and Their Uses

putty knife

Some hand tools like the putty knife are always being reached for in the toolbox. The putty knife is one of the most versatile hand tools you will have in your tool box. It can be used for applying filler materials like wood filler, drywall taping compound, scraping residue and any number of other applications.

A putty knife can come in a number of variations including:

  • Flat edged blade and chiseled edged blade
  • Straight edge and angled edge blade
  • Stiff blade or flexible blade
  • Plastic, carbon steel, stainless steel or brass blade
  • Blade widths from 3/4" to 6" wide

Let's take a look at the different variations and how they are used.

Putty Knife for Spreading and Applying Compounds / Smoothing:

Application of a compound is a common use of the generic putty knife. A compound can include any number of paste-like materials such as wood filler or wood putty, base application drywall compound (used in taping drywall joints), spackling paste or other filler materials or even adhesives.

The blade edge will typically be straight (versus chiseled) and will tend to be flexible (versus stiff). The most economical version of these knives are made from plastic like polypropylene. Plastic blades are often disposable and do not stand up well to continued use. A better constructed blade is made from ground and polished carbon steel.

However, although the carbon steel is more durable, it may rust if not properly maintained. The premium version of a putty knife blade is made from stainless steel. A well made stainless steel blade knife with a durable nylon or wood handle can last a lifetime.

Well made steel blades used for spreading will also have a "hollow ground" feature.

That means the blade is ground to be more narrow in the center of the blade and thicker at the handle and leading edge. What this does is allow a good deal of flex in the blade to modulate the pressure being used when spreading material.

The blade width will vary according to the use of what is being applied. A narrow blade knife is used in tight space applications and where you are applying a small amount of material. Such applications may include wood filler to a hole in wood or a joint crack, or a small hole in drywall being filled with spackling compound. Wider blade putty knifes are usually used for applications of a lot of material such as drywall compound over a wall patch or applied over a taped drywall joint.

Another use of a putty knife is to use it to make clean paint edge when applying painter's tape to an edge such as the top of a baseboard when painting a wall. Use a 1-1/2" flex blade putty knife to press the tape firmly to the baseboard and create a knife edge to the paint line by taking the edge of the putty knife and pressing it simultaneously into the corner of the baseboard and wall and pressing the tape to the baseboard while dragging the knife along the tape on top of the baseboard.

Compare Prices Spreading Putty Knife

Putty Knife for Scraping:
Scraping and removing residue is another use of a putty knife. In this usage however, you will be using a stiff blade (versus flexible) with a chiseled edge (versus flat). You will also want a steel blade instead of a plastic blade. Scraping blades are stiffer than spreading blades so they will not be ground steel (promoting flex). These steel blades will be thicker and more rigid. The chiseled blade edge of the knife should also be angled instead of flat. That will help get under paint or dried putty or other residue easier.

For use in delicate applications and in areas that have volatile fumes, you will want to use a specialty scraper having a brass blade.

A well made scraper will feature a full tang. That is, the metal that makes the blade will run fully through the handle.

That way the knife has metal from front to back and allow the knife to be struck lightly with a hammer on the handle to coax the paint or other debris / residue off the material being cleaned.

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Specialty "Putty Knives":
A couple other specialty types of putty knives worth noting include a taping knife and a multi-tool.

The taping knife is a very wide spreading knife, 9 to 14 inches wide, used to apply wide swaths of drywall taping compound when feathering a drywall joint.

Compare Prices HYDE Taping Knife

A multi tool is a rigid scraping tool with a chiseled edge and special cutouts / edges for cleaning paint rollers, scraping open cracks and scraping material.

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