Since most people use a table saw on wood or sheet metal most of the time, they don’t know how to cut plexiglass with a table saw the right way.
If you find yourself in this category, it’s understandable why working with acrylic might be a scary thought the first time.
In reality, with just a few tool adjustments and changes in cutting speed, your table saw can be just as good for plexiglass as it is for wood or metal.
Here are some tips on how to cut plexiglass on a table saw without chipping it, causing cracks, or getting hit in the face by a flying piece of plastic. It’s really not as hard as you may think.
Choosing the Right Blade
Using a general purpose saw blade for cutting plexiglass is not uncommon. However, while your regular wood saw blade will cut through acrylic if the motor provides enough torque, this will often result in chipped edges or even deep cracks along the surface of your plastic sheet.
For cutting plexiglass you should start by getting yourself a proper blade for the job. Saw blades designed for cutting plastic usually come with 60 or even 80 teeth, as opposed to 24 which is what most wood saw blades have. For most acrylic projects, a 10” diameter blade with carbide-tipped teeth will be enough since you won’t have very thick pieces of plastic to work with.
As tempting as it may be to correct minor mistakes with a jigsaw, this isn’t always recommended. When your finished product is going to have visible edges, getting it done right the first time is essential. Even with the right jigsaw orbital setting, your edges won’t be as even as a table saw cut.
Controlling the Speed
If you want to know how to cut plexiglass with a table saw this is what you need to remember: never force the plastic sheet or push it too fast into the blade. Acrylic is easy to work with but it’s also easy to mess up if you rush the process.
A steady and slow push towards the blade is what you want for your sheet’s edges to come out as smooth as possible. The thinner your sheet is, the slower you should push it as it will have a tendency to vibrate quite a bit.
When making a picture frame, chances are the plexiglass you’re using is very thin. While you may have the right blade and good control over the cutting speed, it may not be enough to make sure that all four edges come out intact. Often times your blade may end up chipping the corner of the glass because that is the sheet’s weakest point.
You can avoid this by using a two-step cutting method and having a couple of extra tools ready: a scrap piece of wood of the same size as your sheet, a push block, and a crosscut sled. Place your expendable piece of wood, preferably plywood, on top of your plexiglass and hold them down firmly with the push block. This keeps them in place and protects you from kickback.
First, you want to perform a small cut into one side of the sheet and then stop the blade. The length of this cut will most likely depend on the size of the sheet you’re working with. Now it’s time to flip the plexiglass with the cut in the opposite direction and do the same for the piece of plywood. Resume the cutting process by following the cut line and this time go all the way through.
Because you’re not applying extra pressure with the blade on to the weak point at the end of the sheet, you will no longer have to worry about chipped corners. This method works for large and small sheets of plexiglass. It takes just a few seconds more but the end result is worth it.
There are two reasons why you would want to apply more pressure when cutting acrylic as opposed to wood. The thin nature of plexiglass sheets causes them to produce more vibrations than wood. This can not only cause the sheet to shift and make you mess up your pattern, but it can also cause kickback.
The problem with kickback is that not only can it shoot a piece of thin plexiglass to your face, but it can also pull your hand towards the blade in the process. Needless to say, that would be very unfortunate especially if you don’t have a flesh sensor on your table saw, which most people don’t.
If you’re still a bit insecure about working with acrylic for the first time and how to cut plexiglass with a table saw, you really shouldn’t be. As long as you remember to use an appropriate blade, a slow pushing speed, steady downward pressure, and crosscutting when necessary, your projects will have smooth edges and close to no visible chips.