Since the rise of active wear and the popularity of athleisure apparel becoming a fashion trend, decorators have needed to find the best methods for printing custom designs onto polyester fabric. When it comes to heat printing on polyester, there are definitely challenges.
The fabric seems difficult to decorate compared to the favorite cotton t-shirt, but don’t be intimidated by polyester.
In addition to already giving heat printers the benefits of wearing polyester and cotton shirts, we’re compiling the Do’s and Don’ts for Heat Printing Polyester so you can get the perfect print everytime!
Don’t Get Too Hot
Temperature plays a major role in heat printing custom apparel. You use a “heat” press to adhere the transfers adhesive or ink to the fabric. The problem with this though is some fabric (ahem, polyester) is sensitive to high temperatures and the fabric fibers can scorch (melt).
So you don’t end up with a permanent, noticeable rectangle on your t-shirts, don’t let your temperature get too hot! The ideal temperature is less than 300 degrees.
Some polyester fabric is more sensitive than others and may require a temperature of as low as 280 to not see scorch marks.
How to tell if the apparel you’re heat printing is ruined.
Do Test the Fabric
The only way to know whether the polyester fabric will scorch or not is to test it.
That’s right, get a sample of the fabric, fire up the heat press to a low temperature like 290 degrees F and press a small corner of fabric.
Did it scorch? No? Then up the temperature to 300 degrees. Press a small corner. Did it scorch? No? Up the temperature again to 310 degrees. Press a small piece of the fabric. Did it scorch? Yes? Then you know at what temperature the fabric scorches at.
This will help you determine the right type of heat transfer to use.
Do Choose the Right Transfer Type
There are several different types of heat transfers at Transfer Express.
Each transfer type has the type of fabric that it is proven to adhere to as well as the time, temperature and pressure that is needed to properly apply the transfer to the fabric.
Polyester is a common fabric that every transfer from Transfer Express will adhere to. However, some polyester is also temperature sensitive, so it’s best to look at the recommended temperature on the Application Instructions to know for sure whether it is the right transfer for the type of garment you’re decorating.
Transfer types like Elasti Prints® and UltraColor® Soft are formulated to adhere at a lower temperature. These will be the best options for printing onto temperature sensitive polyester fabric.
[Samples: Get a free Elasti Prints transfer sample]
Do Check for Dye Migration
Dye migration occurs when the fabric dye is reactivated during heat printing causing the dye to blend or migrates into the decorating material like ink or vinyl.
This dye migration is common in polyester fabrics and fabrics that have been heavily saturated with dye.
Dye migration is extremely prevalent in Sublimated fabrics (pictured right). Sublimated fabrics are made by dying the fabric with a design or pattern.
You can usually pinpoint a sublimated garment by looking at the inside of the shirt. If the shirt has been sublimated, the inside of the shirt is a solid color while the pattern or design is just printed on the outside.
If the fabric you’re decorating has been sublimated or the fabric you’re decorating is known to have dye migration issues, choose a transfer type that is made to block dye migration like UltraColor® Stretch with Blocker or CAD-PRINTZ® Sub Block.
Don’t Use Thick Cover Sheets
Cover sheets are designed to be placed over your heat transfer during heat printing.
Cover sheets like thicker silicone application pads or non-stick 6 mil cover sheets can also help create a heat barrier to reduce scorching on polyester fabrics.
While this might be a perfect solution for preventing scorch marks, what the thicker cover sheets are also preventing is the adequate amount of heat that is getting to your transfer needed to apply.
Screen printed transfers need a precise time, temperature and pressure for application. If you prevent the right temperature from getting to your transfer, you run the risk of a decoration that is under applied.
Stick to thin, paper cover sheets that is sold by Transfer Express if a cover sheet is needed for your application.
Get a Free Sample!
Want a free sample of Elasti Prints® screen printed transfers that are perfect for heat sensitive polyester?
Thank you for the tips you shared on the do’s and don’ts of heat printing a polyester.
You’re welcome, Lisa! Glad you enjoyed the tips.
We are using elasta print transfers. Temp at 285. 15 sec. And 3 for pressure and still getting scorching on 100% polyester shirts. WHY?
WE also used paper on top.
Hi Josylin,
Some polyester is super sensitive to heat. If it is 100% polyester, you can take Elasti Prints down to 275F. However, keep in mind that a cover sheet can also reduce the temperature reaching the transfer application by another 10 degrees. For proper application, you will also want to use medium-firm pressure (6-8).
Have you tested your heat press to make sure it is reading an accurate temperature? You may want to try this test kit: https://transferexpress.com/heat-presses/accessory/heat-press-test-kit
Can I apply heat vinyl to polyester using an iron so I don’t burn it?
Hi Devon,
We recommend using a heat press for the best, most reliable application.
We get orange spots on the back side of polyester blankets after pressing. It occurs with designs that have heavy black ink or blue ink. What is that?
Hi Kevin,
Please send us an email with a photo so we can further help to troubleshoot this with you. Thanks!
https://transferexpress.com/contact-us
Hi Courtney,
You’ll need to use a heat transfer that applies at a low temperature so that the polyester won’t scorch. Generally, around 300 degrees you should be fine, but you’ll need to see how heat sensitive your polyester is. Then you’ll need to order your transfer type or vinyl material in something that applies that low.
Hi, thank you for your tips! I am the new in textile print and I would like to ask for something. I use Blockout htv for polyester on my sport dress clothes for print. Recommended time and pressure is 150-160celsius with medium pressure. The problem is that even if i set up my press maschine up to 150celsius and 15 sec, it leaves scorch marks on my t -shirts.The problem is also probably dark color( black and red). What if I use 140 celsius for 15 sec and than just quick pressure with 150 celsius. Do you think it’s gonna stick? THank you for your help”
Hi Jakub,
Glad you enjoyed the tips! As for the htv, we don’t sell vinyl. We mostly do custom screen printed transfers. We do have several options that are low temperature application if you need some for heat sensitive fabrics. However, for the htv that you specifically have, we would recommend checking with the manufacturer on application settings.
I am trying to press HTV onto Shiny 97% polyester / 3% spandex. I’ve tried everything… following the instructions exactly for the specific type of HTv (sister easy weed and cricut), turning the temp down and pressing longer… nothing is sticking! It is for a friend and I am failing miserably. Please help 🙂
Hi Shannon,
You may want to contact Siser if you are using their HTV products. We sell screen printed transfers. However, what type of heat press do you have? It may be an issue with your press, not the HTV itself.
Your shared post really great.
Thanks for the tip that polyester will melt if it gets too hot. I could see how since it is plastic, that would make sense. I should make sure I get a pro to help me out if I choose to print on polyester so I could avoid using too much heat to transfer the design.
Hi Tyler, as long as you use a transfer that applies at a low temp (below 300°F), you’ll have no problems.
Thank you for sharing on heat printing a polyester. I enjoyed reading the whole article.
I enjoyed reading this article and many points were new for me.
Do you have any idea which transfer vinyl is the best like should I use the pattern or other for the t-shirt design? Which is most durable.
Hi,
Our transfer products are actually screen printed, not vinyl. All of them are independently tested through 50 wash/dry cycles for durability. There is a transfer type for almost anything you need to apply to. This post will help you choose which transfer type is best for your particular job: https://blog.transferexpress.com/how-to-choose-the-best-heat-applied-transfer-for-custom-printing/
Hope this helps!
I am trying to purchase Toiletry bags for my Skincare line. I want to add my Logo to them. However, I am not sure if I should purchase Polyester bags or Recycled PET bags. Any suggestions?
Thanks 🙂
Hi Laura,
You can use either. Just make sure to use a low temperature application transfer like Elasti Prints or UltraColor Soft.
We are here to help There is also a transfer selector tool
very clear and good article easy to understand. Thank you
The post is really amazing and has lots of educational tips and information
Thanks, I’m going to be making my own tshirts soon!
I just received some of the goof proof screen print transfers and followed the instructions and still ended up with marks from the heat press. I tried the higher temp and less time and the lower temp and more time, and both yielded the same results. Any way to avoid that? The shirts are cotton/poly.
Typically the heat marks left on cotton/poly and cotton are simply moisture removal, and as the moisture from the air reenters the shirt, the marks will go away.
After attempting to reduce scorching, researching, reading and watching all the videos including stalhs recommendations which have changed over the last few years.. the truth is if the material begins to scorch at lower temperatures than the transfers recommendations nothing truly works. As they say test the garment, my Team 365 pieces scorch at 240° and get worse the higher as temperatures go up. Even pressing the shirt inside out, there is enough heat to scorch the other side. THERE IS NO DEFINITIVE ANSWER. so with a bottom heated platen you still face the same problems
Most manufacturers note that their polyester won’t scorch at 300 degrees or under. It looks like the brand you are using has an even lower point so if decorating you may just want to switch brands and let the company know why it matters.
Thanks for this!
Thanks for this, just about to do my first ever polo shirt prints for a new client!
I came across your blog post on “Dos and Don’ts of Heat Printing on Polyester” on Transfer Express, and it’s a valuable resource for anyone in the garment decoration industry. Understanding the proper techniques for heat printing on polyester is essential to achieve professional and durable results.
Can you use glitter vinyl on 3.8-ounce, 100% polyester interlock with PosiCharge technology?
Do you know the application temperature needed for the vinyl? I’m sure it would adhere but polyester often scorches at temperatures above 300.