# Why are my thermoflex numbers wrinkled on 100% polyester sports shirt??



## crookedline (Oct 25, 2012)

So, I ordered my first set of pre cut thermoflex numbers from Stahl's. I used my brand new (first use) transpro 15x15 heat press. 330 degrees F for 6-8 seconds as instructed. I did not use a teflon sheet.

The number looked official, a little shiny, but official. I was very happy with the look. I folded the shirt and put it away. Today when i went to wear it, the number looks as if it shrunk a little and is causing several wrinkles on the shirt. Hopefully that makes sense. What did I do wrong? The numbers look fine on the other 50/50 and 100% cotton ones I did...Is this thermoflex not good for 100% poly? Did I do something wrong? Would a teflon sheet have made a difference? Check out the pic:


----------



## Nick Horvath (Feb 26, 2010)

What is your company name? I can look up what you purchased as we do not sell Thermo Flex. Please let me know and I will do my best to help you.


----------



## mrsandman26 (Oct 29, 2012)

Some times stahls thermofilm will retain creases if folded hot.


----------



## crookedline (Oct 25, 2012)

My company is LSR Printing Co. My apologies, its actually Thermo-Film. Is this maybe not the best material for sport shirts, ex: 100% Polyester? Thanks in advance!!!


----------



## Nick Horvath (Feb 26, 2010)

crookedline said:


> My company is LSR Printing Co. My apologies, its actually Thermo-Film. Is this maybe not the best material for sport shirts, ex: 100% Polyester? Thanks in advance!!!


Actually Thermo Film is a great material for 100% Polyester.

As referenced above, did you happen to fold them while still hot/warm?

Was the garment laying relaxed (not pulled too tight) on your lower platen? Sometimes if you pull a fabric really tight and heat apply something to it, the fabric will want to retain its "memory".

Those would be the only things I can think of as Polyester does not shrink nor does Thermofilm.


----------



## crookedline (Oct 25, 2012)

I think after I pressed it I put it on and then set it aside. I'll try to make sure it is not stretched in anyway under the press next time and make sure I let it cool down before wearing it or folding it. We'll see what happens..


----------



## Nick Horvath (Feb 26, 2010)

crookedline said:


> I think after I pressed it I put it on and then set it aside. I'll try to make sure it is not stretched in anyway under the press next time and make sure I let it cool down before wearing it or folding it. We'll see what happens..


Please let me know. Have a great day!


----------



## GordonM (May 21, 2012)

As an aside, polyester *can* shrink, but it's for different reasons than cotton. As the polyester is drawn from the spinnerets at the factory, it's tensioned, which stretches it out, often by 4X to 6X it's original length. When the thread is re-heated to levels commonly used with heat presses, the tensioning of the elongation is reduced, and depending on quality control measures, the material can shrink by varying amounts. The better the thread, the less it'll shrink. A good poly thread should shrink very little.

I regularly sublimate on cheap imported 210D poly totes, which if not pre-shrunk, will result in a blurred image. The fabric can shrink enough to be visible, with puckering around the outlines of the press platen, and certainly enough that it moves under the transfer paper and ruins the image.

Anyway, I don't think it's shrinkage of the shirt here. And to me, your shirt doesn't exhibit the typical signs I've seen in the past from folding while still hot. The wrinkling is mainly in the top rounded part of the 2, and is exactly what I've seen when the fabric is not dimensionally stable when heat pressed. This could certainly occur if the shirt was mechanically stretched at the time of the pressing, as noted above.

If you do it again (with this shirt as a test, even), pre-heat the shirt under mild pressure for maybe 10-20 seconds. Wait for it to cool down a bit so it's not still burning hot, check that the shirt isn't stretched over the platen, then apply the vinyl.


----------

