Working with Plastic: Tips for Cutting and Drilling Acrylic
Plastic is one of those materials that doesn't always get much attention in the woodworking shop. But once you start using it, you'll find plenty of practical applications.
From clear cabinet panels and shop-made jigs to fixtures and machine accessories, plastic can be a useful alternative to wood or glass.
The challenge is that cutting and drilling plastic requires a slightly different approach than working with wood.
Plastic scratches easily, some types are prone to cracking, and too much heat can melt the material rather than cut it cleanly.
Fortunately, you can get excellent results using many of the woodworking tools you already own.
The secret is choosing the right type of plastic, using suitable blades and drill bits, and taking a little extra care during machining.
Acrylic vs. Polycarbonate: Which Plastic Should You Use?
Before cutting or drilling plastic, it's important to understand the differences between the two common types used in woodworking shops: acrylic and polycarbonate.
Although both materials are available in clear sheets, they have different properties that make them better suited to certain projects.
Acrylic (Plexiglas)
Acrylic is one of the most common plastics you'll find at home centers and hardware stores.
You may know it by the familiar trade name Plexiglas.
Acrylic is relatively easy to machine using ordinary woodworking tools, and its clear appearance makes it a good substitute for glass.
For example, you can use acrylic panels in cabinet doors or other projects where you want a transparent surface.
However, acrylic has a significant limitation: It isn't especially resistant to impact.
A hard blow can cause it to crack or break, making it a poor choice for applications where flying debris might strike the material.
Polycarbonate (Lexan)
For applications where impact resistance is important, polycarbonate is generally the better option.
You may recognize it by the trade name Lexan.
Polycarbonate is considerably tougher than acrylic and is much more resistant to cracking or shattering when struck.
That makes it a better material to consider for certain shop guards and protective panels.
However, any machine guard or safety shield needs to be properly designed for the equipment and hazards involved. Material selection alone doesn't guarantee adequate protection.
How to Cut Acrylic Plastic on a Table Saw
One of the nice things about working with acrylic and polycarbonate is that you don't necessarily need specialized machinery.
Many of the tools you already use for woodworking can cut plastic effectively.
A table saw is a practical option for making straight cuts in plastic sheet material.
But there are a few things I do differently when cutting plastic.
Leave the Protective Masking in Place
Plastic scratches easily, especially when you're sliding it across a table saw or workbench.
Fortunately, most plastic sheet material comes with protective masking on both faces.
I like to leave this masking in place for as long as possible.
It helps protect the surface from scratches while I'm measuring, cutting, and drilling.
I remove it only when the machining is complete and I'm ready to install the finished piece.
Use a Fine-Tooth Carbide-Tipped Blade
For cutting plastic on the table saw, a sharp carbide-tipped blade can produce good results.
I prefer a blade with 60 to 80 teeth, which helps produce a smoother cut than a coarse-tooth blade.
Blade geometry also matters, so choose one approved for the particular plastic you're cutting. A blade intended for plastic or nonferrous materials can be a good choice.
Support the Plastic with a Backer Board
One of my favorite tricks for getting cleaner cuts in plastic is using a backer board.
A piece of ¼"-thick hardboard works well.
The backer supports the plastic near the cut and helps reduce chipping as the blade passes through the material.
It also makes thin or flexible sheets easier to support during machining.
Be sure the plastic and backer are properly controlled throughout the cut, and follow the saw and blade manufacturers' recommendations for cutting the material.
Cutting Curves in Acrylic with a Band Saw
A table saw works well for straight cuts, but what if you need to cut a curved shape?
That's where the band saw comes in.
Cutting curves in plastic is similar to cutting curves in wood, provided you use an appropriate blade and avoid overheating the material.
Choose a Fine-Tooth Band Saw Blade
For smoother cuts, I like to use a blade with approximately 10 to 14 teeth per inch (TPI).
The finer tooth spacing helps produce a cleaner edge when cutting sheet plastic.
As with the table saw, I use a backer board whenever possible to support the material and reduce chipping.
Smooth the Edges After Cutting
Even with a fine-tooth blade, the cut edge usually needs a little additional work.
Depending on the plastic and the shape of the cut, you can smooth the edge with suitable abrasives or careful filing.
The goal is to remove saw marks and leave a clean, consistent edge.
Take care not to build up excessive heat while sanding, since that can soften or melt the plastic.
How to Drill Acrylic Without Cracking It
Drilling holes in plastic can be trickier than cutting it.
The main problem is that an ordinary twist drill bit can grab the material as it enters or exits the hole.
That grabbing action can cause cracking or chipping, particularly when drilling acrylic.
You can buy drill bits specifically designed for plastic, but it's also possible to modify a standard twist bit to make it work better.
Modify a Drill Bit for Plastic
A standard twist drill has sharp cutting lips designed to cut aggressively into materials such as wood or metal.
For plastic, that aggressive cutting action can be a problem.
One solution is to grind a small flat on the cutting edges near the tip.
This changes the cutting action so the bit scrapes the plastic rather than digging into it.
The result is a bit that's less likely to grab the material while drilling.
If you don't want to modify your drill bits, a purpose-made plastic drill bit is another option.
Control Heat While Drilling
Heat is another concern when drilling plastic.
Too much friction can soften or melt the material, leaving a rough or distorted hole.
I generally use a slow, controlled drilling approach and avoid forcing the bit through the workpiece.
A drill press makes it easier to keep the bit aligned and control the feed.
For the material and tooling described here, I use the lowest speed on my drill press.
However, the best drilling speed depends on the plastic, hole diameter, and bit geometry, so follow the material and tooling recommendations.
Use a Coolant When Drilling Multiple Holes
When I need to drill several holes in plastic, I sometimes use a small amount of water mixed with a few drops of detergent.
This mixture acts as a lubricant and coolant, helping reduce friction and heat buildup.
It's a useful technique when drilling a series of holes, provided the setup and equipment are suitable for using a liquid coolant.
Always keep liquids away from electrical components and use only coolants approved for the equipment and material.
Tips for Getting Cleaner Cuts and Holes in Plastic
A few simple habits can make working with plastic much easier.
- Protect the surface. Leave the factory masking in place while cutting and drilling.
- Use appropriate blades. Fine-tooth, sharp cutting tools generally produce cleaner results.
- Support the material. A backer board helps reduce chipping during cutting and drilling.
- Avoid excessive heat. Use controlled cutting and drilling techniques to prevent melting.
- Choose the right plastic. Acrylic works well for many clear panels, while polycarbonate is better suited to applications requiring greater impact resistance.
- Test on scrap first. Different plastics respond differently to blades, bits, and cutting speeds.
These small steps can make a noticeable difference in the quality of the finished part.
Put Plastic to Work in Your Woodworking Shop
Acrylic and polycarbonate are useful materials to keep in mind when designing shop accessories, jigs, fixtures, and furniture projects.
And you don't need a separate collection of expensive machines to work with them.
With the right blades, properly prepared drill bits, and a little attention to support and heat, you can cut and drill plastic using familiar woodworking equipment.
The next time a project calls for a clear panel or a durable plastic component, don't hesitate to consider plastic as part of your material choices.
Best Materials for Workshop Cabinets, Jigs & Workbenches
Plastic is just one of the many materials that can make shop-built accessories more useful. But when you're building cabinets, jigs, or workbenches, choosing the right sheet goods is just as important.
Explore Best Materials for Workshop Cabinets, Jigs & Workbenches to learn more about plywood, MDF, hardboard, and other materials that can help you build stronger, more reliable shop projects.
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