Can Polyester Thread Go In The Microwave? (The Answer May Surprise You)

You’re probably used to hearing that you shouldn’t put metal in the microwave, but what about polyester thread? Can it go in there without causing any damage? The answer may surprise you!

So, can polyester thread go in the microwave? No, because polyester is synthetic. And synthetic fabrics should not be microwaved.

Polyester fabric and shirt. Credit: canva

In this blog post, we will explore the safety of microwaving polyester thread and provide some tips on how to do it safely.

Fabric and Microwave

Is It Safe to Put Fabric in the Microwave?

fabric microwave
Fabric and microwave. Credit: canva

The quick answer is yes, it is safe to put the fabric in the microwave. However, there are a few things you should keep in mind before zapping your fabric in the microwave.

First, make sure the fabric is made of natural fibers such as cotton, linen, hemp, silk, or wool. Most natural fabrics can be microwaved safely. Synthetic fabrics should not be microwaved.

Second, check the label on the fabric to see if it is pre-shrunk. If it is not, then microwaving it could cause the fabric to shrink.

Finally, always test a small piece of the fabric in the microwave first before microwaving the entire piece.

Fabric Products that Might Need to be Microwaved

There are a few products made of fabric that you might need to put in the microwave.

  • Hand warmers. These are small packets that you can put in your pocket or gloves to keep your hands warm.
  • Microwavable heating pads. These are pads that you can place on your body to relieve pain or soreness.
  • Warming towels at the spas. At some spas, they will give you a towel that has been warmed in the microwave.

Can Polyester Thread Go In The Microwave?

No, it is not recommended to put a polyester thread or any other polyester product in the microwave.

hand warmer
Hand warmers. Credit: canva


Polyester is a synthetic fabric. Because they are produced artificially, tend to have different levels of plastic in them, which will melt in the microwave.


Microwave-safe products

The only time you could put a polyester product in the microwave is if it is specifically made to be microwaved.

For example, there are some oven-safe polyester bags that can withstand high temperatures. These products will have special instructions on how to use them safely in the microwave.

Filled with other matter

heating pad
Heating pad. Credit: canva

If the polyester fabric is filled with enough other matter, such as rice, to absorb the microwave’s waves, you might be safe having it in the microwave for a short period of time.

One example is polyester heating pads. These are often filled with rice or other materials, and the filling will help to absorb the microwaves.

Not too long

Even if the polyester can withstand being in the microwave, you should not leave it in there for too long. The heat can cause the polyester to break down and release chemicals.

Let’s say you have a polyester food container. If you don’t leave the food in too long, then it will warm up the food instead of the container. On the contrary, if you do leave it in for an extended period, eventually the heat will cause the plastic to melt.

Use caution

Even if you are using a microwave-safe polyester product, it is always best to err on the side of caution. When in doubt, don’t put it in the microwave.


To sum it up, can polyester thread go in the microwave? No, you should not put a polyester thread or any other polyester product in the microwave.

The reason being is that polyester is synthetic and will melt when exposed to high heat.

There are some exceptions, such as if the product is specifically made to be microwaved or if it is filled with other materials, but it is always best to err on the side of caution.

Related Topics

What is Mercerized Thread?

Mercerized thread is a type of thread that has been treated with a caustic soda solution in order to give it a high degree of luster and strength.

Is It Better to Sew with Cotton or Polyester Thread?

It really depends on what you’re sewing and what your priorities are. For example, if you’re sewing a garment that will be worn in hot weather, cotton thread is a better choice because it’s more breathable than polyester.

On the other hand, polyester thread is more durable than cotton, so it might be a better choice for something that will get a lot of wear and tear..

Which is Stronger Cotton or Polyester Thread?

A polyester thread is stronger than a cotton thread. Polyester is a synthetic fiber, so it’s more resistant to wear and tear than cotton.

However, cotton thread is more elastic than polyester, so it can be a good choice for projects that require a lot of stretches, like knitwear.

Can I Use Polyester Thread for Potholders?

Yes, you can use polyester thread for potholders. However, it is not as heat-resistant as cotton thread, so it’s best to use cotton thread for projects that will be exposed to high temperatures.

What is the Strongest Thread for Sewing?

The strongest thread is probably Kevlar, which is often used in bulletproof vests or other high-strength applications. It’s incredibly strong and resistant to heat and abrasion, making it ideal for sewing threads that will see a lot of wear and tear.

However, it can be difficult to work with and is quite expensive, so it’s not always the best choice for everyday projects. 

Can Flannel be Microwaved?

Flannel is a type of fabric, not a thread. However, you can microwave flannel if it is 100% cotton and doesn’t have any metal accents. Be sure to follow the care instructions on the fabric to ensure that it is safe to put in the microwave.

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