Here's a new drywall cutting blade that fits in an electric reciprocating saw. It's perfect for cutting holes in drywall on walls and ceilings, but not the things hidden behind the drywall.
Q. I'm a remodeling novice, and I'm going to be doing some drywall work soon. I've never worked with the material and have no idea how to cut it. Not only do I have to cut new sheets to size, but I also have to make cutouts in existing drywall walls and ceilings. A friend suggested I use a circular saw. That makes sense to me. What tools and techniques do you use to cut drywall? I'm interested in accuracy, speed and safety.
A. I clearly remember one weekend driving to a potential customer's house to look at a job. His next door neighbor had a sheet of drywall laying flat on two sawhorses out on his driveway. He was attacking the drywall with a circular saw creating so much dust that I thought the EPA was going to issue a county-wide air quality alert. Suffice it to say I offered this man the some of the same advice I'll offer to you.
First, don’t use a circular saw to cut drywall. It’s like using a rock to hammer nails. Both are the wrong tools for the job. A circular saw creates giant clouds of unnecessary dust. This dust causes premature wear on the moving parts of the saw, as well as your lungs and those of anyone standing nearby.
Professional drywall hangers use a regular razor knife to make straight cuts on drywall. Standard drywall, or Sheetrock, is simply a sandwich product. It’s comprised of two outer layers of special paper that conceal a gypsum-based core. Each drywall manufacturer might have a special recipe of ingredients found in the core, including fly ash from power plants.
This fly ash can contain silica, and it’s simply not a good idea to inhale silica dust. Doing this can contribute to, or cause, a serious lung disease, so it’s best to minimize dust when working with drywall. Spinning saw blades work well with wood because they normally create a harmless dust for the most part.
To cut a straight line with drywall and create minimal airborne dust, you just score one side of the drywall with a sharp razor knife. Apply enough pressure to completely cut through the paper and into the gypsum core about ‰-inch. You need to cut this line all the way across the piece of drywall from edge to edge.
After making the cut, you go to the other side of the drywall and apply pressure directly behind the cut line. This pressure causes the drywall panel to snap along the cut line and bend over completely on itself. You finish the cut by simply cutting through the paper backing on the other side of the drywall panel.
Standard drywall is ½-inch thick. You can use this method to cut off pieces as narrow as 1½ inches wide. If you need to cut narrower pieces from a sheet of drywall, it requires you to make deeper cuts with the razor knife into the gypsum core. Do this carefully so the razor knife cuts only the drywall and not you.
To make cuts into existing drywall that’s screwed or nailed to walls or ceilings you can make repeated cuts with a very sharp razor knife, but it’s very time consuming and hard to do. The gypsum core creates a large amount of friction making the cutting difficult.
You can use a hand-powered saw that’s especially made to cut through drywall. The blades are tapered and have a sharp tip that allows you to push it through the drywall with relative ease. The biggest problem is that these blades are normally about 5 or 6 inches long, and they can easily reach wires, cables, pipes and other things hidden behind the drywall. A rookie like you can easily create big and expensive repair problems in a hurry using one of these tools.
A new short metal blade specifically for cutting holes into existing drywall has been developed for electric-powered reciprocating saws. The blade has a blunt tip, and it’s only about 1¼-inch long. It doesn’t have sharp teeth, but rather square notched cutouts. It does a splendid job of cutting drywall, but won’t cut deep enough to harm anything behind the drywall, especially if you hold the blade at a 45-degree angle as you glide it across the surface of the drywall.
Be careful when cutting holes in drywall ceilings. Always wear safety goggles, not safety glasses. Drywall dust and small chunks of gypsum core in your eyes can cause you to make an expensive trip to an emergency room or eye doctor.
Professional drywall hangers use a small rotary cutting tool fitted with a bit that looks like a standard drill bit. This bit has special cutting edges on the spiral shaft that allow it to cut rapidly through drywall. These tools are used by every professional drywall hanger that I know. While they increase productivity by a factor of five or more, they also create clouds of dust.
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