6 minute read -
Cutting Plastic: Which Saw and Which Blade for Each Type of Plastic?
Plastic is best cut with a jigsaw for curves and a circular saw for long straight cuts, in both cases with a fine-toothed blade made for plastic. Keep the speed moderate and the feed steady so the material does not melt. The lower the melting point of the plastic, the more carefully you need to cut.
Cutting plastic cleanly comes down to three things: the right blade, the right speed and a sheet that cannot vibrate. Get those right and most sheets and profiles cut as easily as wood.
What will you learn in this article?
- Which saw is suitable for plastic?
- How do you cut plastic with a jigsaw?
- How do you cut plastic with a circular saw?
- Which plastic needs which approach?
- Why does plastic melt while cutting, and how do you prevent it?
- How do you finish the cut edge neatly?
- Which safety precautions should you take?
- Common mistakes when cutting plastic
- Frequently asked questions about cutting plastic
- In short: cutting plastic
Which saw is suitable for plastic?
For plastic sheet and profiles, three saws are the most useful.
| Saw | Best for | Watch out for |
|---|---|---|
| Jigsaw | Curves, cut-outs, shorter straight cuts | Pendulum action off, support the sheet well |
| Circular saw | Long straight cuts in sheets | Fine-toothed blade, use a guide |
| Handsaw or fine-toothed saw | Profiles, small pieces | Light pressure, steady pace |
On the Maxxpack 18V battery platform, one battery powers both a cordless jigsaw and a cordless circular saw. For plastic, a tool with variable speed is the most useful, so you can match the speed to the material.
How do you cut plastic with a jigsaw?
The jigsaw is the most versatile choice. You can use it for straight lines, curves and holes.
- Choose a jigsaw blade for plastic or a fine metal-cutting blade. Fine teeth give a smooth edge.
- Switch off the pendulum action. Pendulum cutting tugs at the sheet and causes chipping or cracks.
- Start at a medium speed and turn it down if the plastic starts to melt.
- Lay the sheet flat and support it close to the cutting line. Vibration is the main cause of chipped edges.
- Connect dust extraction if your saw allows it. Plastic chips are static and stick to everything.
For a cut-out in the middle of the sheet, first drill a hole large enough for the blade.
How do you cut plastic with a circular saw?
For long straight cuts, a circular saw is faster and straighter. The blade makes all the difference. Use a carbide-tipped blade with many teeth that is suitable for plastics and non-ferrous metals. These blades often have a triple-chip tooth or a negative hook angle, so they do not grab the material.
An HSS blade is not a usual choice for plastic sheet in a circular saw. A fine carbide-tipped blade stays sharp for longer and leaves a neater edge.
- Set the cutting depth so the blade comes out a few millimetres below the sheet. That means less vibration and less heat.
- Use a guide rail or a clamped batten.
- Cut in one even movement. Stopping halfway leaves a melted spot.
- Leave the protective film on the sheet while cutting.
Which plastic needs which approach?
Not every plastic behaves the same way. Check the sheet or packaging to see what material it is.
Rigid PVC
Rigid PVC cuts well with a fine blade at a medium speed. It becomes brittle in the cold, so cut it at room temperature if you can.
PE and PP
Polyethylene and polypropylene are soft and have a low melting point. Cut slowly, at a low speed, with a blade with slightly coarser teeth that clears the chips well. Fine teeth clog quickly with these materials.
Acrylic (Perspex)
Acrylic is hard and brittle. It can crack or chip with vibration and too much pressure. Use a very fine blade, clamp the sheet close to the cut and keep the protective film on. Do not go too slowly, though, or the cut heats up and welds itself shut behind the blade.
Polycarbonate
Polycarbonate is tough and does not break easily. It cuts more easily than acrylic, but it also gets hot. A fine-toothed blade and a steady feed give the best result.
Why does plastic melt while cutting, and how do you prevent it?
Friction creates heat. Once the plastic gets hotter than its melting point, the material sticks to the blade and the kerf closes up behind the saw. You can prevent this as follows:
- Lower the speed.
- Use a sharp blade. A blunt blade rubs instead of cutting.
- Keep a brisk, even pace. Pushing too slowly is just as bad as pushing too hard.
- Let the blade cool down for a moment after a long cut.
- If in doubt, choose a blade that clears the chips well, so the heat leaves with them.
How do you finish the cut edge neatly?
Cutting often leaves burrs and small melted ridges. Remove them with a deburring tool, a sharp knife or a fine file. Then sand with fine abrasive paper, for example 240 grit followed by 400. With acrylic you can then polish the edge for a clear finish.
Which safety precautions should you take?
- Wear safety glasses. Plastic chips fly in all directions.
- Wear ear protection when cutting with power tools.
- Work in a well-ventilated space. Melting plastic gives off fumes you do not want to breathe in. If you see smoke, stop and lower the speed.
- Wear a dust mask for longer cutting or sanding sessions.
- Remove the battery when changing the blade.
Common mistakes when cutting plastic
- Using a coarse wood-cutting blade, which chips the edge.
- Leaving the jigsaw's pendulum action switched on.
- Leaving the sheet loose, so it vibrates and cracks.
- Cutting soft plastic at full speed.
- Removing the protective film too early.
Frequently asked questions about cutting plastic
Which saw blade should you use for plastic?
For a jigsaw, choose a blade for plastic or a fine metal-cutting blade. For a circular saw, use a carbide-tipped blade with many teeth suitable for plastics and non-ferrous metals. For soft plastics such as PE and PP, a blade with slightly coarser teeth works better.
Which speed should you use for plastic?
Start at a medium speed and see how the material reacts. If it melts, turn the speed down. Hard plastics such as PVC and acrylic can take a little more speed, soft plastics such as PE and PP need less.
Can you cut plastic with a handsaw?
Yes, a fine handsaw or hacksaw works well for profiles and small pieces. Cut with light pressure and long strokes. For large sheets, a power tool is faster and straighter.
Why does my Perspex crack when I cut it?
Usually because of vibration, a blade that is too coarse or too much pressure. Clamp the sheet close to the cutting line, switch off the pendulum action and use a very fine blade. Leave the protective film on until the cut is finished.
In short: cutting plastic
Use a jigsaw for curves and a circular saw for long straight cuts, always with a fine blade made for plastic. Match the speed to the material, keep the sheet clamped and vibration-free, and cut at a steady pace so the plastic does not melt. Finish the edge with a deburring tool and fine abrasive paper.
