# Scorch Prevention on Lights?



## Stitch-Up (May 26, 2007)

Yesterday, I pre-treated a grey T and cured it in the same way I cure black shirts - 325deg F. There was a distinct scorching of the shirt.

So, assuming I print the shirt with a white underbase and then colour, how can I survive scorching the shirt? It seems that if I use the same methods as I do with black shirts, I'm going to scorch them.

I've tested the temerature of the platen with a high quality tool and it reads 325deg F.

John


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## IYFGraphics (Sep 28, 2009)

Stitch-Up said:


> Yesterday, I pre-treated a grey T and cured it in the same way I cure black shirts - 325deg F. There was a distinct scorching of the shirt.
> 
> So, assuming I print the shirt with a white underbase and then colour, how can I survive scorching the shirt? It seems that if I use the same methods as I do with black shirts, I'm going to scorch them.
> 
> ...


John...325F should not hurt the shirt, when you do your printing, just use a small amount of pressure (or none) with your heat press for the duration you need will work, do a test sample and see how it works out.

Hope this helps.


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## Stitch-Up (May 26, 2007)

I only use pressure for the curing of the pre-treat & to ensure the fibres lay flat, it's during this stage the scorching occured


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## equipmentzone (Mar 26, 2008)

Are you scorching just the area that was pretreated? Or does the untreated part of the grey shirt also scorch?

Harry
Equipment Zone


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## Stitch-Up (May 26, 2007)

Hi Harry

The scorch is taking the shape of the platen, I'm pretty sure part of the scorched area had no pre-treat on it.

I pressed the pre-treated shirt for 90secs @325deg F.


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## IYFGraphics (Sep 28, 2009)

Stitch-Up said:


> Hi Harry
> 
> The scorch is taking the shape of the platen, I'm pretty sure part of the scorched area had no pre-treat on it.
> 
> I pressed the pre-treated shirt for 90secs @325deg F.


That seems a long time to cure pretreatment, try knocking it down to 30 sec total, do like 20 sec covered, then open the press remove the cover sheet then press again for another 10-15 sec, should be enough to get a good cure.

Hope this helps.


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## equipmentzone (Mar 26, 2008)

It could be that the specific grey shirt you are using is of a quality that cannot stand extended heat. Easiest way to check is to press an untreated shirt and see what happens.

Harry
Equipment Zone


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## Stitch-Up (May 26, 2007)

IYFGraphics said:


> That seems a long time to cure pretreatment, try knocking it down to 30 sec total, do like 20 sec covered, then open the press remove the cover sheet then press again for another 10-15 sec, should be enough to get a good cure.
> 
> Hope this helps.


I used to press for 20 secs and only changed to a longer time after reading threads here. I'd prefer to press for 20 secs for obvious reasons 



equipmentzone said:


> It could be that the specific grey shirt you are using is of a quality that cannot stand extended heat. Easiest way to check is to press an untreated shirt and see what happens.
> 
> Harry
> Equipment Zone


The shirt was supplied by a customer and the label says Gildan Ultra but, I'm aware some sources of shirts sell 'copies', I'm thinking this might be the case.

I make clients aware that if they supply the clothing, it has to be replaced at their cost if we screw-up!

John


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## equipmentzone (Mar 26, 2008)

For drying pretreatment you should only have to go 20 seconds. I recommend 330 degrees as the temperature. However you still need to heat set the ink after you print so you still may have a problem with scorching the shirt since you should heat it for 90 seconds then.


Harry
Equipment Zone


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## IYFGraphics (Sep 28, 2009)

Stitch-Up said:


> I used to press for 20 secs and only changed to a longer time after reading threads here. I'd prefer to press for 20 secs for obvious reasons


If your don't have a problem with a 20-30 second cure, there is no reason to change, the amount of pretreatment your applying to the shirt would make the difference in the amount of time needed to cure, if your getting the shirt "wet" then it will require more time to dry the pretreatment.

It's really what works for you in your environment with your setup...that's all that matters, what works for us may not work for you because of differences in humidity, application, heat press....etc.

Hope this helps.


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## Stitch-Up (May 26, 2007)

equipmentzone said:


> For drying pretreatment you should only However you still need to heat set the ink after you print so you still may have a problem with scorching the shirt since you should heat it for 90 seconds then.
> 
> 
> Harry
> Equipment Zone


This is the issue, I have to cure the inks so the effect would be the same regardless of the time I take to cure the pre-treatment. Perhaps not entirely true, but you get where I'm coming from.



IYFGraphics said:


> If your don't have a problem with a 20-30 second cure, there is no reason to change, the amount of pretreatment your applying to the shirt would make the difference in the amount of time needed to cure, if your getting the shirt "wet" then it will require more time to dry the pretreatment.
> 
> It's really what works for you in your environment with your setup...that's all that matters, what works for us may not work for you because of differences in humidity, application, heat press....etc.
> 
> Hope this helps.


My environment is probably 70 to 80% humidity today!

I'm from Wales, UK - well known for its rain, beer and gorgeous women aka, my partner Angie


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## IYFGraphics (Sep 28, 2009)

Stitch-Up said:


> My environment is probably 70 to 80% humidity today!
> 
> I'm from Wales, UK - well known for its rain, beer and gorgeous women aka, my partner Angie



LOL...John, with that much humidity are you prepressing the shirts to remove moisture? still you should be able to get by with a much lower cure time, I'd do a few tests to see what will work and adjust up or down from there.

Hope this helps.


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## erich (Apr 15, 2009)

usually the scorch mark is just the starch in the shirt.

Often it will fade naturally within a 24 hour period or it will wash out.

wet your finger and rub on the scorch mark, if it starts to lift off straight away then it will wash right out.

Jerry
DTG Digital


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## Stitch-Up (May 26, 2007)

The scorch mark is set for good I'm afraid, the wet finger didn't rub it away.

The customer supplied another shirt, same brand, same country of origin. As you can imagine, I was very cautious, maybe too cautious as it seems the inks didn't cure sufficiently - only discovered after the customer received the shirt - ouch!

Does anyone here have problems with Gildan shirts from Nicaragua?

One thing that is different with the shirt is that it has 10% poly! I always use 100% cotton and the gray shirt was the only cotton/poly mix I've printed to.

John


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## equipmentzone (Mar 26, 2008)

Did you get scorching on other brands of shirts using the same heat settings?


Harry
Equipment Zone


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## Stitch-Up (May 26, 2007)

equipmentzone said:


> Did you get scorching on other brands of shirts using the same heat settings?
> 
> Harry
> Equipment Zone


No Harry.

The customer supplied other shirts of the same brand & model, most were black & there was one white. They all printed just fine with the exception of the grey! It was the only shirt supplied with a polyester content @ 10% The only other difference was that it was made in Nicaragua - I don't think this is uncommon.

The customer is very understanding but of course, would like an exclamation. As of yet, I don't have anything conclusive.

Cheers

John


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## equipmentzone (Mar 26, 2008)

It could just be that specific batch of fabric that was used to sew that shirt. Could be caused by how the factory dyed that batch or how the blend was woven. You may get the same color and brand from the same country, produced on a different date, that may be fine using your same heat settings. 

Harry
Equipment Zone


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