Cutting Plastic With Dremel

The Dremel rotary tool is a staple in many DIY toolboxes. Among its many uses is cutting plastic. This task isn’t difficult, but it does require some knowledge since you can ruin your workpiece if you do it incorrectly.

Can a Dremel Cut Plastic?

The Dremel Multi-Tool is an excellent rotary tool for cutting plastic. When you use the correct cutting disc and speed setting, the plastic will not melt, and you’ll create a neat, smooth cut.

Dremel can cut through hard plastics such as ABS, nylon, and plexiglass.

There are various Dremel cutting discs suitable for cutting plastic. The one you use would depend on the application. Typically, thinner cutting discs would be matched with thin plastics. You would use thicker, reinforced cutting discs for thicker or solid plastics.

Will the Plastic Melt?

When cutting plastic using a Dremel Tool, it’s best to do it at low speed. High-speed cutting causes friction between the cutting disc and the workpiece, generating heat. Excessive heat generation will cause the plastic to melt, potentially ruining the cut and the workpiece.

Typically, thinner cutting discs cause less friction since they don’t remove as much material per rotation as their thicker counterparts. Unfortunately, these thinner discs tend to be more fragile and thus tend to break easily.

Thicker plastics are also more prone to melting while cutting. Here, the cuts are deeper than for thinner workpieces, so you might spend more time cutting in one position. This leads to localized heat build-up, which causes the plastic to melt.

Depth of Cut

When cutting plastic with a Dremel cut-off discs, you’re limited to a maximum cut depth of 1.1” (2.8cm).

The cutting discs have a maximum cutting radius of 0.6” (1.5cm), so to reach a depth of 1.1”, you would have to cut the workpiece from both sides.

Dremel Plastic Cutting Bits

There are various Dremel bits suitable for cutting plastic. The bit you use depends on the plastic you’re cutting since some plastics are harder than others, and some have lower melting points.

What Dremel Bit Cuts Plastic?
Typically, you would use one of these bits to cut plastic:

Dremel EZ476 Plastic Cutting Wheel

This cutting wheel was designed to make straight cuts and slots in plastic, specifically vinyl and plexiglass. Using this cutting wheel will produce smooth edges and clean cuts, requiring little to no finishing work afterward.

Note that this cutting disc often doesn’t form part of the default bit set bought with the multi-tool, so you may have to buy it separately.

Cutting Wheel #409

This cutting wheel is meant to cut metal, but it does a reasonably good job cutting most plastics. The Metal #409 bit has a smaller brother, the #420, which is also great for cutting plastic. The #420 is a thinner cutting wheel, so it cuts through plastic slightly quicker.

Unfortunately, this thinness renders the cutting wheel more brittle, causing it to break when you apply pressure to it. This is a potentially dangerous situation when you’re not using the proper safety gear.

You must wear mask and safety glasses when using Dremel. I would recommend a face shield when using cut-off wheels, as these discs can shatter and cause serious injuries.

The #420 wears out faster than the #409, so you may need extra cutting wheels for a bigger job.

Mini Circular Saw Blades

You can get a small slitting saw from third-party manufacturers that can be mounted onto the standard 402 Mandrel.

This type of saw blade works well on plastic and softwood. However, do not attempt to cut too with it. Keep in mind that the circular saw blades actually penetrate and cut through the plastic whereas the abrasive cutting discs mentioned above grind the material away.

Multipurpose Cutting Bit #561

This cutting bit is suitable for making detailed plunge cuts in plastic. Examples include cutting circles in the middle of large plastic sheets.

Dremel Max Life 117HP

The Max Life High-Speed Cutter (117HP) is a curve-shaped carving bit suitable for cutting wood and plastic. It’s coated with Titanium Nitride for improved wear resistance, giving it longer service life.

This cutting bit is meant for carving, engraving, and freehand routing applications.

How to Cut Plastic With a Dremel?

Cutting plastic using a Dremel Multi-Tool is relatively simple.
Here’s a step-by-step guide to the process.

1. Choose the appropriate cutting bit. For best results, match the bit to the workpiece’s material. A good rule of thumb is to use a smaller cutting wheel when cutting thin plastics while matching thicker, reinforced cutting wheels with solid plastics.
2. Install the bit. The EZ Lock system makes installation quick and easy.
3. Secure the workpiece in a clamp or vice. This ensures safe and accurate cutting.
4. Mark the cut line.
5. Put on the appropriate safety equipment. This includes gloves, safety glasses or face shield, and potentially earplugs.
6. Connect the Dremel to the power supply.
7. Set the speed. Dremel recommends a speed between 10000RPM and 15000RPM for cutting plastics. Exceeding 15000 RPM might cause the workpiece to melt. If you’re unsure which speed matches your workpiece, start cutting at a low RPM. Increase the RPM as needed.
8. Switch on the Multi-Tool. Grip the Dremel firmly, preferably using a two-handed golfer’s grip.
9. Start cutting. Do this in steady, smooth movements. The Dremel bit will do the cutting, so you don’t need to force it or apply pressure. Slow, steady movements will help you create clean, straight cuts.
10. Adjust the RPMs if necessary. Higher RPMs make for straighter, smoother cuts, and they get the job done faster. If your material can handle higher RPMs, adjust the speed upwards. If the plastic starts to melt, lower the speed again.
11. Switch off the tool.
12. Add finishing touches if necessary. The edges of the cut may be rough, in which case you may need a sander bit to smooth it out.

How Do You Smooth Plastic With a Dremel?

Smoothing plastics with a Dremel is quite easy. Attach a sanding disc or polishing bit to your Dremel tool and sand the workpiece. Typically, you would use this when smoothing cut edges or 3D prints.

Choose lower speeds as with the cutting procedure since the plastic will melt at high RPMs.

Dremel’s steel polishing bit typically offers a smoother finish, but it’s harder to control than the sandpaper discs. If you’re confident in your ability to control the Dremel in detailed work, the polishing bit might be the tool for you. If not, instead, opt for the sandpaper discs.

Alternatively, you can use a sanding block to sand manually. I usually sand straight edges by hand and polish curves and shapes with the Dremel.

How to Cut Straight with a Dremel?

You can use the Dremel Multi-Tool to create both straight cuts and plunge cuts in plastic.

There’s no secret to doing straight cuts when using cutting discs– simply hold the cutting bit to the desired cut line. Plunge cuts can be slightly tricky since you can’t necessarily create the detail you need with this type of cut.

Dremel line and circle cutter attachment is an optional accessory with which you can get perfectly straight cuts parallel to an existing edge.

However, you need to use a multi-purpose bit and need a clean edge as a reference for the line cutter attachment.

Can You Drill Plastic With a Dremel?

The Dremel tool is capable of drilling plastic, though you are limited by the diameter of the bit that the collet or chuck can hold. To drill larger diameter holes, you may need a spade drill or hole saw mounted on a cordless drill or drill press.