[discountprinting]

I am looking for clarification of the temperature for heat pressing a full color plastisol transfer. I am using 613Originals Classic formula (white underbased for dark shirts). I am pressing 100% cotton and the instructions slip says:
"375° 7 seconds 60psi hot peel"

Which of the following answers is correct?

A) The 375° is referring to the target temperature setting of the heat press digital readout which results in the temperature of the garment/transfer/plastisol inks running somewhat cooler (15-20° or so) as the heat is transferred and dissipates to the transfer/garment.

B) The 375° is the target temperature the transfer/garment needs to reach for good adhesion of the plastisol inks

A quick search on curing temperatures of plastisol inks suggests a curing range of 300-330° depending on the brand of ink, which is for straight screen printing but does these numbers change when using a plastisol heat transfer?

I understand there is some latitude with regards to the quality of the heat press used as to how accurate the temperature is as well as other factors such as time and pressure.

I appreciate you help,
John

 

[splathead]

Only the ink has to get to cure temperature, not the garment. Putting a 375 degree hot plate on a sheet of paper with ink on it will cause both the paper and ink to get up to 375 rather quickly.

Are the instructions not working for you?

 

[discountprinting]

Only the ink has to get to cure temperature, not the garment. Putting a 375 degree hot plate on a sheet of paper with ink on it will cause both the paper and ink to get up to 375 rather quickly.

Are the instructions not working for you?

I guess I am questioning why 375° when most plastisol inks cure between 300-330°F. I did some tests and the color is not as bright as I think it should be at 375 the red (100% M 100%Y) is dull compared to at 350 it is more red but still could be brighter.

 

[splathead]

I guess I am questioning why 375° when most plastisol inks cure between 300-330°F.

Because full color transfers for darks has 5 layers of ink. Their spot color transfers don't require that high a temperature.

 

[discountprinting]

Because full color transfers for darks has 5 layers of ink. Their spot color transfers don't require that high a temperature.

So if the colors are dull would you back off the temp?

 

[splathead]

So if the colors are dull would you back off the temp?

I would ask 613 if they have a safe lower temperature you can go. I know with Versatranz, Dan had mentioned at one point his transfers that normally transfer at 320 could go as low as 310-305 with wash tests.

But with any deviation from published temps, wash tests are critical.

 

[TABOB]

I guess I am questioning why 375° when most plastisol inks cure between 300-330°F.

Plastisol should never reach 375F. That's just the recommended temperature of the heat plate.
The theory is that within the 15 seconds of pressing time, conduction will raise the temperature of the ink layers to somewhere between 300 and 350 F.
These settings are only guidelines, and you should do your own tests to find the optimal settings for your own equipment.

I did some tests and the color is not as bright as I think it should be at 375 the red (100% M 100%Y) is dull compared to at 350 it is more red but still could be brighter.

There is nothing much you can do about this.
It depends on how the transfer was made, and red ink layer is probably too thin.
Try pressing at a lower temperature for longer 350F for 30 seconds for example.
You may also have to try different pressure settings.

 

[discountprinting]

Thanks that's what I was thinking