100% Poly Performance Fabric-Shrinkage Temp?

[alan802]

Of course we have a problem with some shirts we recently printed that were the typical under armour 100% poly performance material and the customer is complaining that none of them fit.  The sales staff has been talking with the supplier and they are saying that the shirts will shrink at 320 degrees.  We all know these shirts will shrink but I have never read anywhere other than a pdf they sent that this shrinkage takes place at 320.  We also know that bleeding will begin around 260-265 degrees and that is well documented all over the place.  When printing these shirts we have a completely different temp and belt speed setting and according to the donut probe tests this setting gets the inks up to about 305-310 which is dangerously close to not curing the ink properly.  We use low bleed white inks that cure at under 300 but any other colors might be of who knows what ink manufacturer so those inks are at risk of washing out with our current settings for polyester garments.  2 years ago we had to reprint a job like this due to major shrinkage but since then we've not had any issues and the new dryer helped out a ton.  So since that reprint we have always lowered the temp and time for poly shirts but now it seems we have had another issue and I need to figure it out before this happens again.  Getting the ink to cure properly and keeping the garments under the shrinkage temp isn't impossible as we all know but at our shop we use a ton of different inks and we aren't able to use the low bleed, low cure temp inks 100% of the time on poly shirts due to many other circumstances. 

Does anyone know or have ever heard of an exact temperature that we see poly fabric shrinkage?  I think that they shrink at lower temps (below 320) depending on the quality of the garment, some shrink much worse than others.  I know that we've kept this poly setting for a long time without any problems and although it's been a while since I measured any shirts for shrinkage I don't think this recent issue is on us.  I know we'll end up paying for it and making it right but I wonder if anyone has any real numbers on poly fabric that I can draw anything from.

[screenprintguy]

Hey Alan, we had an issue last year with Sport Tek ST350's. They would bleed really bad which is a reason we went to performance inks by wilflex for that type of printing, since it cures under 300, fixed that, but then also, the switch of the ink helped us see that if the shirt go up to 310 degrees plus or minus a couple degrees, it would come out the other end 5/8 of an inch smaller than before it went it. Sanmar actually relplaced a huge order of them for us because the shrinkage was way more than they allowed. We ended up doing several tests with the red ST350 to narrow down, 290 degrees max to have no shrink no bleed. Not sure if the other brands matter, but we've been following that same set of parameters for any 100% poly and even 100% poly compression shirts and have had no issues since the one last year.Suuuuuuuuuposedly by one of the product reps at SPA, if you add wilflex stretch additive to performance inks, you lower the cure temp to closer to 270, we've played it safe, but he swore on that info.

[ebscreen]

Man, that's a tough one. Unfortunately I think it is really going to come down to the fabric itself.
For example:

Once we had an order for a bunch of poly from Sanmar. They were white, so I aimed more for
sure cure than dodging bleeding.

We've printed the hell out of ST350's in every color and never had any issues. This  particular
order they were out of a size we needed so Sanmar suggested the ST700.

ST350's printed/cured fine. The first ST700's that came out of the dryer had burned through
only where we had printed black ink. It was a new one on me.

End result is that the ST700's were a much much thinner fabric and couldn't hang with the heat.

I highly doubt that any mill is able to keep fabric weights at an exact number, I just don't think
that's the nature of the beast. Nor are distributors able to tell when there are variances.
That leaves us to find out, and also typically leaves us holding the bag. At least we're over-compensated for it!
(unt unt unt)

[ebscreen]

Oh, and sorry I don't have any specific numbers for you, just our experiences with poly fabrics.

[aauusa]

There really is no magic number for the heat on these.  It will vary between brands and even in the lots of the same brand.  What we have learned to do is run 1 blank shirt through at dry speed and see what changes are made in shirt size compare it to the no ran thorugh dryer shirt.  If there is a large noticeable difference then we either let the customer know about the issue if they brought the shirts in.  Most of the time the brands we use never have that issue it always customer supplied garments.



You can actually go to Boombah site which sells blanks to the customer for printing and they say if you screen print order a size larger for shrinkage issues. 

[alan802]

Of course these were customer provided.  A4 is the brand I think.  We've printed quite a few of these for this customer too, never a problem until now.  This sucks because we take the proper precautions and do what we're supposed to do and it's still going to be a groin kick.  Print looked damn good too.