Plexiglass is a transparent acrylic plastic that is often used in the place of glass, so you might at some point be faced with the prospect of having to saw a piece of plexiglass to size.
While a table saw is the easiest way to cut plexiglass, it has its drawbacks as well, since plexiglass is a thermoplastic.
A thermoplastic is a kind of plastic that can be melted down again and repurposed. It tends to melt under friction and the heat generated by a power saw is bound to melt plexiglass.
This is why you have to choose the blade you’re going to use with care and you also need to saw with care.
Plexiglass is popular to use in the place of glass as it does not shatter or crack.
For this reason it’s also the ideal material to use for greenhouses – the plexiglass lets in the optimum amount of light that plants need, but is still a robust material that can withstand rough weather conditions.
Tip: Use a push block to keep the plexiglass in place while you work. The push block provides 3-directional force that keeps the material you work with safely in place on both sides of the blade to keep it from vibrating.
The push block provides a downwards force that keeps the plastic in place, a force from the side to keep it against the fence and a forward force to keep it moving forward.
This is important because uncontrolled vibration can lead to rough edges which you want to avoid.
You don’t have to buy a commercial push block. They are quite simple to make and you can find many videos on YouTube on how to go about it. It’s worth investing time or money into getting a push block if you want to keep all your fingers.
Cutting plexiglass with a table saw
Step 1 – Safety first
Always use safety glasses when you are working with your table saw – you don’t want small shards of plastic hitting you in the eye.
Step 2 – Check the thickness of the plexiglass
Measure the thickness of your chosen plexiglass with a tape measure. Only plexiglass that is ¼” thick or thicker can be cut with a table saw.
Anything thinner will chip badly or simply melt because of the friction caused by the saw. Only ¼” plexiglass or thicker is safe to cut with a table saw.
Step 3 – Choose the correct saw blade
Make sure the blade is sharp and clean. Some woodwork enthusiasts recommend using blades with 50 to 60 teeth. More teeth than this mean more friction and heat which might melt the plastic.
A blade with fewer teeth is also recommend for the softer varieties of plexiglass as they tend to melt with a lot of friction.
The opposite goes for harder plexiglass, which needs a blade with more teeth to prevent chipping. A carbide-tipped blade is best. Ensure that it is perfectly parallel to the fence.
Step 4 – Measure the cut you want to make
Measure the size of the cut you wish to make and mark it on the plexiglass.
Note: Keep the width of the saw into account when you are setting the fence to hold the plastic in place as it will take up a tiny amount of space, which could cause your measurements to be slightly off.
Step 5 – Use a push block
Use a push block to hold the plexiglass and push it through the blade. This safety device is a must for any table saw work. It helps you to safely move the plastic sheet through the blade while keeping it flat against the fence.
Step 6 – Make the cut
Turn on the saw and push the plexiglass through the saw using a slow and smooth movement. If you use force or move the plastic too fast you will cause the edge to chip.
The push block and fence will ensure that the cut is perfect and that all your digits stay where they belong.
Be sure to hold the plexiglass firmly against the fence during the cutting process.
If you see that the edges are getting chipped, change the blade to one with more teeth; if the plastic melts, change the blade to one with fewer teeth and slow down as you push the plastic through the saw.
Also, consider that the sheet might be too thin or too soft to saw.
Try rather to score and snap it. To save time, you can saw a few plexiglass sheets at the same time by stacking them on top of each other. Use clamps to keep the sheets from shifting.
Step 7 – Sand the edges
The edges of the plastic might have melted in the sawing process. You can take care of this by sanding the edges down with some fine grit sandpaper.
Whenever you need to cut plexiglass, all you need is the right blade and proper support from a push block for a perfect job.