How Do You Cut Hard Plastic Without Breaking It?

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Cutting hard plastic is no easy task. Not only can the cuts be hard to make, but you also run the risk of breaking it in the process. However, there are some techniques that you can utilize to ensure you don’t break your plastic while cutting it.

​How Do You Cut Hard Plastic Without Breaking It?

There are a few different ways to cut hard plastic without breaking it. Provided that the hard plastic is less than 1/2″ thick, you can use a string or hot knife to make a straight, downward cut. If the hard plastic is thicker, use a circular saw for cutting.

The best method for cutting plastic depends on the size of the piece and the kind of cuts you need for your project.

​To cut hard plastic without breaking, it, you can either use a piece of string, various types of saws, or a hot knife. You can also pre-drill small holes along your cut line to prevent breakage and make the piece easier to cut.

How To Cut Hard Plastic with String

You can cut through oddly shaped and hard pieces of plastic, like PVC pipe, ​toy cars, and model ​figures with cotton thread. The concept is simple. You make a saw-like blade using a piece of cotton thread.

Here are the step by step instructions:

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  1. Secure the plastic piece to your work surface with masking tape or clamps.
  2. Grab a needle and a pair of pliers. Grip the needle using the pliers and then heat the needle with a lighter.
  3. Use the hot needle to make a hole in the plastic somewhere along your cut line.
  4. Take a spool of cotton thread and pass one end through the hole you just made. Keep the spool end on the top side of your piece.
  5. Give yourself about a foot of working thread and wind the loose end around one hand.
  6. You want to pull the thread until it is tight and then use it like you would a saw to cut your plastic piece, pulling the string back and forth. 

It takes patience and work, but you can make a clean cut in plastic without breaking it using a piece of cotton thread.

How To Cut Plastic with a Saw

There are a few kinds of saws that will cut plastic without breaking it. A saw is a good choice for cutting flat or thick pieces of plastic. You can use a hacksaw, fine-toothed saw, circular saw, or jigsaw to cut plastic. 

If you use a hacksaw or circular saw, you’ll also need a plastic cutting blade. Avoid using saws or blades with large teeth because they will chip or break the plastic and create rough edges. You want a saw with a fine-toothed blade to cut plastic.

high quality jigsaw is a great option, as these tools are incredibly versatile. Jigsaws work really well for these types of material, like cutting plexiglass.

If you choose the hacksaw, jigsaw, or fine-toothed saw to cut your piece of plastic, you’ll want to secure it to your work surface with clamps before you make your cut.

Whenever you cut plastic with a saw, you should wear eye protection and make sure to hold or clamp the plastic to keep it from wobbling or breaking. Mark your cut line and cut slowly to minimize melting.

How To Use a Hot Knife for Cutting Hard Plastic

You can modify a soldering iron tip to create a hot knife to cut hard plastic.

  1. Use a mallet or hammer to flatten a soldering iron tip.
  2. Use the modified tip to cut through hard plastic.

The hot knife method minimizes the chances that your plastic will break. It also makes clean cuts and can be used to make curved cuts. However, many people don’t have a soldering iron on hand. 

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How to Use a Drill to Cut Through Hard Plastic

You can use a drill to make small holes along your cut line, prior to then using a different tool for the final cuts

  1. Use a corded power drill on a slow speed and a small drill bit. 
  2. Once the holes are drilled, you can use a utility knife or fine-toothed saw to cut the remaining plastic.

The drilling method reduces the chances that the plastic will break and also makes it easier to cut along the line and through the plastic. Use this method in tandem with another we recommend for the best results. 


An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.