[Seansurfn2]

Hi,
Was noticing the shirts im printing and putting in the hot press after its pre-treat is laid down are all getting medium scorch issues.

Shirt being used is a 100% cotton gildan shirt
did some testing with the normal they had here at work
set at 75psi and 350 degrees F and 40 seconds. The shirt which really shows the discoloration would be the Olive shirt which turns yellow. What i've read so far on here is that perhaps the pressure and temp are too high but even putting it in for 15-20 seconds i'm seeing it scorch still almost immediately.

I'm also fairly new to all this and want to make sure that all the shirts hold up for my customers.

Should i dilute the pre-treat fuild with water a bit more? i tried with different spray setting to try to sort out some variables but its tough considering just last week i learned how to print on the gt-782 =P

any help would be greatly appreciated!

 

[bornover]

Do you have a way to actually measure the temperature of the press? Do the shirts do the same thing when not pretreated?

 

[spiderx1]

Is it a scorch or a discoloration due to heat dye interaction that may go away after a few hours. I have this on red shirts and it goes away after a while. Next what does the shirt do if pressed with no pretreat. If that's ok then it's back to the pretreat which brings us back to Bornovers suggestion on what is the real temp. I have 2 presses and one runs 30 degrees hotter than it says. I use 330 for 20 secs then check to see that it's dry. I would not dilute the pretreat. Is it dupont. Fresh or older pretreat u may have gotten with a used machine?

 

[Don-ColDesi]

You can try pressing the shirt i two steps - one minute times two.

 

[FatKat Printz]

are you using parchment paper or a Teflon sheet???

 

[Seansurfn2]

nope i just put it in 340 F and 40 seconds at 40psi now without any pre-treat and there is no discoloration or scorch at all

 

[Don-ColDesi]

75 pounds is a lot of pressure. My guess is that the steam is not being allowed to escape at that pressure, lighten it up a bit and see if it gets better.

 

[Seansurfn2]

i know the pre-treat was diluted 50/50 water/pre-treat solution and filled it to be exactly twice the weight it was originally. shirt without pre-treat doesn't do that at all. I've been changing the psi/heat to see if the problem persists or goes away. Seems that right now the pre-treat is clearly the problem.
Now when you use teflon paper which i have i haven't been using it on the first press which is right after i apply the pre-treat. Now do you put the teflon paper on top or inside the shirt when pressing? im just using junk shirts right now of course so i can screw things up without wasting good shirts

 

[Seansurfn2]

75 pounds is a lot of pressure. My guess is that the steam is not being allowed to escape at that pressure, lighten it up a bit and see if it gets better.

ya i set it to 40 psi now i notice sometimes the steam releases out the sides and gets sucked up by the fan hooked up. ya to me 75psi seems pretty high as well and it was what it said on the machine so i assumed it was correct.

 

[teehive]

You are going to get a little discoloration with the heat press but it should not burn the garment. With my Stahls hotronix heat press the settings are 356 degrees for 35 seconds and about 7 or 8 on the pressure. I use a teflon sheet on top and bottom. When the garment is finished with printing and still discoloration try spraying water on it, it should help out.

 

[FatKat Printz]

Do not dilute your pre-treat I know you don't want to waste it but you need to know exactly how it looks on the shirt at full strength.

that's a good choice to use junk shirts..but if the junk shirts have been pre-washed or have fabric softener on them that could be a problem too.

what kind of press do you have??
what kind of parchment paper are you using?
are you using a Wagner or pump spray?

 

[Seansurfn2]

Do not dilute your pre-treat I know you don't want to waste it but you need to know exactly how it looks on the shirt at full strength.

that's a good choice to use junk shirts..but if the junk shirts have been pre-washed or have fabric softener on them that could be a problem too.

what kind of press do you have??
what kind of parchment paper are you using?
are you using a Wagner or pump spray?

The press is a K20S
Teflon paper is being used as well.
im using for pre-treat the viper XTG 6000.
Shirt is an olive green color and looks almost a brown/yellow tint no matter how short i heat it on the press it turns that color quickly. sprayed water on a section and it just dissappears or so.... shirts are shirts that have mis-prints on them from our screenprinting lab in the back of the building but shouldnt have any fabric softener or anything on them.. the solution was 50% water and 50% pre treat because thats how it was being used for quite awhile and what the owner here said to do =P im not really getting any scorch at all on the maroon shirts i messed around on

 

[Don-ColDesi]

What pre-treatment are you using? When diluting it are you diluting with distilled/de-ionized water or tap water? How does it look if you apply the pre-treatment with an HVLP like the Wagner? What answer did your distributor/dealer of your direct to garment printer give you?

 

[Don-ColDesi]

PS - try washing one of the shirts before you pre-treat it and see if you get a different/better result. It could be a sizing compund in the shirt itself that is reacting with the pre-treatment

 

[bornover]

The press is a K20S
Teflon paper is being used as well.
im using for pre-treat the viper XTG 6000.
Shirt is an olive green color and looks almost a brown/yellow tint no matter how short i heat it on the press it turns that color quickly. sprayed water on a section and it just dissappears or so.... shirts are shirts that have mis-prints on them from our screenprinting lab in the back of the building but shouldnt have any fabric softener or anything on them.. the solution was 50% water and 50% pre treat because thats how it was being used for quite awhile and what the owner here said to do =P im not really getting any scorch at all on the maroon shirts i messed around on

As mentioned, the dye in a garment can react to the heat (red garments seem to do it the most). But once I really thought about what you said about how much pressure you were using, it was way too much. This is how I do my pretreat and things I have learned.

Heat press at 330 degrees verified with IR heat gun (many here say they are not very accurate but it works for me).

Prepress garment at medium pressure for ten seconds to flatten fibers and get wrinkles out.

Spray garment with full strength pretreatment.

Dry garment with non-coated paper over it for 20-30 seconds with very light pressure. (lots of steam and I try not to breath it)

To much preatreament leads to a print that will peel in the wash. If you can't dry the preatreament in 30 seconds you are probably putting too much on. On a black or very dark shirt you definitely want to use full strength pretreatment. I have found that you need to dry the preatreament and even cure the ink with light pressure so the water vapor can escape. If you use too much pressure the ink does not actually cure properly.

 

[Don-ColDesi]

Sean,

Still trying to find out what pre-treatment you are using. From what I can see from your first post it may be a Brother 782. You have posted this in the DTG Brand section of the forum so folks are giving you advice based on their experience with that brand of machine and pretreatment. The Brother uses a whole different pretreatment than the Epson based machines do.