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How to Use a Hot Knife Safely and Properly

To all the people who ever thought that sewing was a "safe" hobby, I present the hot knife. It's a knife that heats to extremely high temperatures to cut and seal synthetic materials. These are extremely useful tools and are easy to handle. It's also way too easy to hurt yourself in the process. Many experienced crafters get a bit too comfortable with their hot knife and seriously burn themselves. 

What Can a Hot Knife Do?

It's actually amazing what a hot knife can accomplish. They can easily cut out and even shape synthetic fabrics and materials. But they go even beyond cutting and shaping. They seal it with a completely seamless edge. That means no bunched-up singed fabric, just smooth edges. 

The most common materials that benefit from this seamless edge include:

  • Webbing
  • Rope
  • Sailcloth
  • Gaskets
  • Carpet

Anyone can easily find these tools in hobby and craft shops as well as in kitchens and workshops. The thing to keep in mind is that you're handling a heavy-duty and extremely hot knife. We can't emphasize enough that it's both hot and sharp. Enough accidents happen in kitchens and sewing rooms, but now the two are coming together, and we're a little concerned. So always take proper care to ensure that you're using it properly. 

How to Use Your Hot Knife

Preparation is half the battle of any crafting adventure. It's even more important now because you don't want to damage your table or counter. Put down a glass sheet. Any other material or surface will sustain permanent damage. 

Ensure the glass sheet is flat and then lay out the material. Open any windows or be sure that you're in a ventilated area because there will be fumes.

Every cut is permanent, so carefully measure and double-check your pattern. Then, you can get to actually working with the hot knife. 

A hot knife has a double-edged heated copper tip that slides on and off. Start by plugging in the device with the tip on and wait a few seconds for it to heat up. Then, hold the hot knife like you would a pencil. 

You'll notice from the first second that this knife does cut smoothly, with no resistance. It's important not to pause during cutting because it can disrupt or ruin the material. As you finish cutting your material, you can be completely confident that it won't fray or unravel. 

Using Your Hot Knife

Hot knives work because they melt the material, which means that they only work on synthetics. Any natural materials won't have the same result. 

You can use a hot knife on:

  • Acrylic
  • Dacron
  • Nylon
  • Ropes
  • Carpet

But if there is a cotton-blend or any natural materials such as wool, the knife will have disastrous effects. 

There are lots of opportunities to use hot knives, even if it seems like the material selection is limited. Here are a few examples of common hot knife applications:

  • Cutting rubber
  • Cutting and sealing fabrics
  • Removing adhesive
  • Wire stripping
  • Removing rubber coatings
  • Designing and installing upholstery
  • Installing and cutting carpets
  • Sealing packages
  • and more! 

If you're looking for a new tool to add to your sewing room, you might consider a hot knife instead of another sewing machine foot attachment or storage cubby. 

GoldStar Tool

If you need a hot knife for your next project, check out our selection here! Please contact us if you have any questions about any of our products. If you use any of our products or tutorials, please tag us on Instagram! We love seeing your visions come to life!