Screen printing problem

[JONESYS]

Can some one tell me what im doing wrong. I bought me a press and done some shirts and let them air cure 24 hrs. And then HEAT pressed them at 350 deg. For 5 sec. And washed them and the print cracked. And the front of the shirt were i printed is coming off i used plastisol white ultimate color.

 

[reximages]

A good conveyor dryer would erase your ink cure problem. White ink you need to flash cure on first pass just enough to the the touch, then your second print on top of that.

You have a flash dryer, right?

The ink is not cured correctly if it cracks. 350 is too hot. 320 is the cure point for plastisol.

 

[JONESYS]

Don't have a flash dryer yet just got the SHIRT press I was running some samples.

 

[G-Artist]

Plastisol will not cure until PROPERLY heated. That is great. You could leave plastisol in the
screen for days or even weeks, pull it a few times with a squeegee and you can start reprinting.

Can't do that with other screen-print inks.

The can or the literature should have the cure temp. and dwell time.

Air drying does nothing.

Never "press" a plastisol ink. You can use a heat press to dry the ink on a shirt but the
heat platen should never, ever, touch the ink.

Anyone who irons a plastisol garment will find that the ink will remelt and possibly screw
up the iron as well. Customer should be given a "care sheet" which tells them to wash the
garment inside out (to prevent abrasion) and to dry at low temperature as well to never
apply heat near the print.

 

[JONESYS]

Thanks for the info and the replys. Just getting started and didn't know not to use a heat press i was using a teflon sheet.
Have any suggestion for me without a flash dryer or a conv. Dryer.

 

[Farmboy]

I would suggest you at least get a flash. You can cure your shirts with that. It's not the best way to do it, but you can. Also, do not let your shirts sit with uncured ink on them. The shirt will slowly wick the plasticizer out of the ink and all you'll have left is pigment sitting on your shirt. The temps that were mentioned above are a good guide line. 320 is the recommended temp, not the holy grail though. Dwell time under that heat is just as important. 350 or higher as a surface temp isn't to high. If your printing whites or any opaque ink that's been printed more than once hitting a surface temp of 320 may not cure the ink all the way through. This is important when your starting out as "newbies" tend to really lay ink on heavy. That's not a slam against you, just how it is.

 

[JONESYS]

Thanks, thats commin sense leting the shirts wick i didn't think about that thanks for pointing that out the first shirts i done in white with a 110 mesh and a 1/8 of gap it took 3 to 4 swapes to get a good even coat. It was probly heavy on the shirt. Then i done some more in red and it only took 1 swape using another screen mesh but the screen was a little losser.didn't make sense to me i tought the thighter the screen the better unless red flows better. Thanks for you alls help look like im going to have to invest. Again lol.

 

[G-Artist]

If you are printing white on a dark color and assuming you already have a seriously opaque
ink and still not getting good coverage, you can 'cheat' slightly by adding a small amount of
the same brand's puff ink (or puff additive) and mix throughly so you don't have to make
4 squeegee passes. Even pulling some ink out the can and mixing it for a short while in a
clean container either by hand or with a drill attachment will increase the flow properties.

The squeegee type you use (durometer) as well as the blade shape can play an important
part in how many pulls you will need to effect proper ink coverage. Play with that on pelon
squares before pulling a shirt print.

Sometimes using off-contact won't work. Sometimes 110 mesh just isn't coarse enough, especially
for thick white.

And some days no matter what you do - it is far simpler to flash after the first pull to get
the best coverage.

 

[JONESYS]

Thanks, for all the input.i guess i will go back to doing samples. And get me a flash dryer. You all are great.

 

[Mosh]

We use 60 mesh for printing on darks. You need a dryer or don't even bother selling shirts. A flash unit is not going to cut it, and I have no idea what you are trying to do with the heat press. Heat press is for putting transfers on, nothing to do with direct screening.

 

[tomence]

if you dont have the money for flash dryer go to home depot and get yourself industrial heat gun, probably cost around $30 its better than having nothing, other than that you gonna have to get a flash dryer its easier and faster. Conveyor dryer is big so if you work out of your room its not gonna fit.

 

[Flame]

Thanks for the info and the replys. Just getting started and didn't know not to use a heat press i was using a teflon sheet.
Have any suggestion for me without a flash dryer or a conv. Dryer.

Heat gun. A heat press is NOT for screen printing, what so ever. You must either get a flash dryer or use a heat gun.

 

[Pro Image]

Hey I sent you a PM........

 

[killergraphics]

Until you get a flash or better yet a dryer.
You can use a teflon sheet or wax paper on top of the ink while on the heatpress.
Very little pressure and at 350 for 30 to 40 seconds to start.
Pill the paper cool to cold.
Then do a wash test.

 

[screener24242]

WM Plastics Eco Aqua Pura doesn't need a flash dryer, conveyor dryer or heat press. .just a fan.

 

[killergraphics]

Very true. That is some really good waterbased ink.
And will fully air dry in a few days. And wash in a week or so.

 

[G-Artist]

I'll take some issue with not using a heat press to dry, especially for short runs.

Quite some time ago there was an article in one of the print mags...maybe Sign of the Times or Printwear.

In it they did a profile on a shirt shop. The outfit had 13 heat presses used for drying plastisol prints. Seems like they had a very expensive conveyor where one or more, but not all, of their heat elements died and yet the print was dry to the touch. Shipped out 100's of 4-color prints that week which they ended up eating plus loss of a client. The owner said it was a great solution and a bit cheaper than maintaining his conveyor.

Necessity is the mother of invention and in that case the solution worked and was far more reliable for that company according to the owner.

Teflon sheets, wax paper, etal is unnecessary and could be a hindrance. Just set the press to not touch the print. Use temp strips at 4 corners to make sure the heat is adequate and even across the print. The important part is to fully cure the ink and to not overcook the ink nor scorch the print/shirt.

 

[tomence]

No matter what for plastisol ink you need a conveyor dryer if you want quality. Playing with teflon sheets and heat presses thats for little kids.
Once you setup the dryer you will be flying doing 75-80 shirts an hour one color. Using other methods to dry its gonna take you all day to finish 80 shirts.

 

[killergraphics]

Yes if you are going to screen print do it right and not just make due.
The dryers come in all sizes and be found used very often.
I'm a little over 400 a hour.
I would hate to heat press those.

 

[Mosh]

A heat gun? Heat presses? Are you guys doing this as a hobby or professionaly?
If so use the right eqipment or don't do it. Plastisol needs to be cured at 420
a setting a heat press over a shirt is not going to cure it completely, no matter how long you sit it there at 350 it is now going to get to 420. This post is almost embarrassing that a professional shop would suggest crap like this....