7 Tips to Press Polyester Seams and Creases Without Melting Them
Polyester is everywhere nowadays. A vast majority of commercial clothing is made out of polyester and a lot of the fabrics sold off the bolt are also made from polyester or poly-blends. While sewing is usually not a difficult type of fiber to work with, it still poses some challenges. The main problem you’ll face is in using heat with your polyester fabrics and garments. Since the material is more or less plastic, it will melt at high temperatures, making it difficult to use an iron to press seams during the sewing process.
The best way to press stubborn polyester seams, darts, and pleats is to use a press cloth. This will allow you to use a higher temperature on your iron to press the polyester without melting it. You can spray water on the press cloth to create steam to further help press the seams.
Of course, there is always more than one way to do everything when it comes to sewing. Try any of the options from this list to figure out what works best for your fabric and sewing process. Make sure to test on a scrap piece of fabric before trying to press your final piece.
1. Press on the wrong side of the fabric
Since polyester has the unfortunate tendency to melt when you press it, you always want to work from the reverse side of the fabric. This way, if it does get a bit too hot and starts to melt, the worst of it will be on the back of the garment and you won’t make it unusable.
This is good practice in general, no matter what fiber your material is made from, but it’s even more important for polyester since it cannot stand up to high temperatures at all.
2. Use a low heat setting when ironing polyester
The first thing to try is to see if you can press the polyester enough using a low-heat iron. Use a scrap of fabric to see how hot you can make the iron without melting the polyester. With the iron just under the melting point, see if there is enough heat to press the seam (or dart, or pleat) as you usually would with a cotton garment.
Some types of polyester fabric will flatten just fine even on low heat settings. If that’s the case, congrats, just make sure you don’t overheat the iron.
However, usually, this is not going to be enough to get you a nice, crisp seam or pleat. You’ll need to take some extra steps to help your fabric along. You can choose a technique from the next few steps to find the way that you like best to fully press your polyester fabric.
3. Use a press cloth to iron polyester
The first thing that I reach for when the polyester fabric is not cooperating is a press cloth. A press cloth is just a piece of fabric you use in between your garment fabric and the iron. It gives a little bit of a buffer to keep the hot plate from directly melting the fabric. You can turn your iron to a higher temperature (usually significantly higher), which will allow you to press the garment underneath.
You can buy press cloths from just about any fabric store if you want to. But, you could also just use any old piece of cloth (usually cotton is best) and use it as a press cloth. Usually, you’ll want to find something that’s untreated and not dyed. I just use a length of white cotton broadcloth that’s left over from an old sewing project of mine.
4. Add heat and hold your cloth in place
The disadvantage to using a press cloth is that you can’t really see what’s underneath. It’s difficult to know for sure if the polyester fabric is flat or if you’re accidentally pressing extra creases into it.
If using the pressing cloth is impractical for your garment, you can try using your fingers instead (please do not iron your fingers, that’s not what I mean!).
- Iron your seam as usual with a cool iron.
- When you remove the iron, you can touch the fabric and see that it’s still hot to the touch. The heat is temporarily making the plastic fibers more malleable and easy to manipulate.
- You can press the seam or pleat flat with your fingers, using the residual heat to your advantage.
- If you keep the seam pressed flat with your fingers, the plastic fibers will almost re-harden or reshape in place as the seam cools down. This way when you remove your fingers, the seam stays flat.
5. Use a heavy book to crease pleats (or a tailor’s clapper)
Very similar to the last tip, you can use a tool called a tailor’s clapper instead of your fingers. If you don’t have one, any type of flat heavy object will do, like a book. This is great for when your fingers are sensitive and the polyester is too hot to touch. You use a book or clapper to hold it in place instead. This method also works better for pleats that may need to be held down for longer than a simple seam.
6. Add moisture with a spray bottle or steam iron
If you are dealing with a stubborn seam, you might need to use steam to help get it to sit flat. If you have a good steam iron, this is as easy as using the steam settings to help you out. But if you don’t, you can still use steam to your advantage.
To use steam to press your fabric without a steam iron, you’ll need a press cloth (same thing that I mentioned in part 3 above), and you’ll need a spray bottle filled with water (I’ve seen some people mention that a vinegar and water solution works well, but that’s not something I’ve ever tried. Feel free to test it if you want to).
- Place the press cloth over your garment.
- Spray over the area you’re going to iron with your water. You don’t want to completely soak it, but it’s okay to be generous with your spray bottle.
- Heat up the iron and press the seam. You’ll immediately create steam that will help you create flatter seams.
7. Use a rajah pressing cloth
If nothing else works, there is a type of cloth you can get that’s treated with chemicals that make it easy to press pleats, darts, and seams on polyester clothes. This is called a Rajah pressing cloth by the company Sullivans. You use it the same way you would any other pressing cloth, but it works wonders in creating creases (or getting rid of creases) in polyester fabric.
The Rajah pressing cloth is a bit difficult to find. I haven’t been able to find a listing for it on Amazon or Joann’s Fabric. But you can usually locate it at smaller specialty stores if you look around a bit.
