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screen printing => Ink and Chemicals => Topic started by: Denis Kolar on June 06, 2011, 10:33:44 AM
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Is it possible to over-cure the ink. Is it too much to read 360-370 degrees at the dryer's end. I have a small electric dryer, Atlas 824, 8' long with 4' chamber and 24" belt. I had to run some shirts 3 times, front print, back print and I noticed that they crack when stretched slightly so I ran them again (Only with the heavier deposit facing the IR panels). Now I have issues with the ink washing out when washed.
Thanks
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Other considerations for cracking too, like ink deposit thickness, etc. but generally, ink washing off is undercure. Ink cracking is overcure.
The entire ink deposit needs to reach cure temp, not just the surface. That can be the problem with IR temp guns, they only measure the surface.
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I have them coming out at around 400 ish...the tags get e lil' curl...
I am constantly checking the sides of the artwork to make sure it doesn't crack...the middle of the shirt gets hotter than the sides when going through so I adamant about checking the sides.
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not an expert here, but I would say not under those circumstances. How long are they at those temperatures? How thick is the ink deposit?
It would be nice to hear something from the manufacturers though!
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This was 110 mesh P/F/P.
I noticed that is was funky after the first cure, so I ran them again trough the dryer.
BTW, how did this end up being a separate post? I thought I posted this a s reply to "Curing Ink" question I had before.
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not an expert here, but I would say not under those circumstances. How long are they at those temperatures? How thick is the ink deposit?
It would be nice to hear something from the manufacturers though!
Pierre, you have seen my dryer. I do not know when they reach that temp, but they are in the dryer for a good 25-30 seconds.
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I moved it into a separate thread thinking it would get more answers (it did!) 8)
from what I am seeing, that looks undercured to me. 25-30 sec in the dryer is not the measurement, it is how long is it at temperature. Get your temp gun and see how long is the shirt in there and above 300 deg. If it is only a sec or two, you will need to slow down your belt. If they are getting out at 380 right now, they might be even hotter when slower, so I would drop the temp too so they are still getting out at 375 or so. I know that is hot and you will have problems with 50/50's but for most jobs, I would imagine it should do. For bleeders, you might have to slow down and drop the temp even more.
'not an expert, just my observations, so I could easily be wrong. Some of the gurus here can you please confirm or correct me?
pierre
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They appear to not be cured sufficiently.
Especially with small dryers you may find that a few inches on the edges of the panels are not really useful, ie, don't plan on curing an 18" wide print on an 18" wide panel.
It is not uncommon for shops with big prints and small panels to run shirts through multiple times, each either rotated or shifted to one side or the other. When you find yourself at that point too often, it's time for a bigger dryer.
Drafts can add to this problem.
In answer to your first question, yes, you can over cure plastisol, but you aren't doing that here.
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They appear to not be cured sufficiently.
Especially with small dryers you may find that a few inches on the edges of the panels are not really useful, ie, don't plan on curing an 18" wide print on an 18" wide panel.
It is not uncommon for shops with big prints and small panels to run shirts through multiple times, each either rotated or shifted to one side or the other. When you find yourself at that point more too often, it's time for a bigger dryer.
Drafts can add to this problem.
In answer to your first question, yes, you can over cure plastisol, but you aren't doing that here.
This one has 2 24" panels, 2 exhaust fans and 2 fans that are pushing the air in.
I have exhausts on, but should I have the other two fans on to push the air down or that is for water based ink only?
No draft, I'm in a basement without any windows that can open.
I thought that these are undercured, but I was told differently :( Also, another thing, it seams that the other design on a black shirt printed with 156 mesh feels a bit better, I still need to do wash test.
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110 is a pretty thick ink film, it would be hard to get that cured all the way through, not impossible, but it does take longer than a 230 or 156.
I run most of mine at 156 or 230, I like a little thinner ink film.
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Also, another thing, it seams that the other design on a black shirt printed with 156 mesh feels a bit better, I still need to do wash test.
You will notice a difference between curing a black tee and a white tee. Black/darks absorb heat (curing easier) while white tees reflect heat more.
I like the look of that washed out cracked print. You can tell them it's part of the trendy process only seen after it's cured like discharge. In this case, you need to wash it first to get the full effect. (but will cost an additional .50 per shirt.) HA HA.
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Thats definitely under cured. When I had a smaller dryer I ran mine just under the blistering point of the ink. Never had any issues with washing out or cracking. If your shirt is cracking even if it is cured I would take a look at using a higher mesh. A 110 is like laying down a coat of drywall mud on the shirt. When the ink is that thick its going to crack no matter how long you cure it.
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I did the washout test on the black shirts that were printed through 156 mesh, nothing washed out. I do not like how the print looks, and the pull test does not pass, but at least they do not wash out.
How do you guys do the cure test, do you try to pull the ink apart to see if it cracks (slight pull) and do you do the scratch test?
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I pull a bit to check stretch without cracking, but have always been taught that multiple washings are the only sure way.
There is also a solvent test, but I'll be darned if I even remember what was used.
Now, you say that you don't like the look, they "pass the wash test" but not the pull. Does that mean that a gentle stretch makes it crack? How does it look? Is it blistered, did you really toast it? Or is the look you don't like a lack of opacity?
How about a pic of it as well?
We also may need some of our ink folks to explain some technicalities here.
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If your electric dryer has a scrub air feature normally used for water based inks, it will help to keep it running at all times. The circulating air helps to equalize the temperature in the dryer and minimize hot spots near the center of the belt.
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Andy.
The ink cracks when it is slightly stretched. I have some that I printed before with Wilflex white and those are not cracking when stretched.
I will take a pic tonight when I get a chance. I was also told to look on the inside of the shirt if I could see the ink from inside, in case I had pressed the ink too hard. That is not the case, the ink stayed on the top of the shirt and I can not see anything inside.
MrBreeze.
It is electric and it has two small fans in the middle that push the air to the inside of the dryer, but only to the middle of the dryer (it covers the whole width of the tunnel/belt but only on the half way of the heat chamber). Also, it has two exhaust fans.
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If Wilflex was working for you why did you step away from it?
I think you have another problem than just your ink. You should have no problem laying down a great print with a 156. Our lowest mesh for the manual is a 156. We dont even have a 110 in the shop. I know this is stepping away from the thread a bit sorry.
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If Wilflex was working for you why did you step away from it?
I think you have another problem than just your ink. You should have no problem laying down a great print with a 156. Our lowest mesh for the manual is a 156. We dont even have a 110 in the shop. I know this is stepping away from the thread a bit sorry.
I did have a quart sample of Wilflex and I printed some shirts with it. In the meantime I switched to the white that everyone was raging about.
I recenntly started printing and I heard a lot of people were using 110 mesh, now I have sold half of mine 110's and I will kep just a few and start from 156. I will do 156, 200 and 230 for spots.
Thanks
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Are you flashing and hitting these a second time? If you are it is possible that you are over flashing the first print.
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Are you flashing and hitting these a second time? If you are it is possible that you are over flashing the first print.
I flash for 5-6 seconds and usually the first layer is tacky but no ink stays on my finger. I did the same thing on blacks as I did on reds, the only difference is the mesh count.
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If Wilflex was working for you why did you step away from it?
I think you have another problem than just your ink. You should have no problem laying down a great print with a 156. Our lowest mesh for the manual is a 156. We dont even have a 110 in the shop. I know this is stepping away from the thread a bit sorry.
I did have a quart sample of Wilflex and I printed some shirts with it. In the meantime I switched to the white that everyone was raging about.
I recenntly started printing and I heard a lot of people were using 110 mesh, now I have sold half of mine 110's and I will kep just a few and start from 156. I will do 156, 200 and 230 for spots.
Thanks
Just an FYI. I have heard from someone else that they are having the same problem as you with that white. I have some of it too but I have not had that issue yet. I wont be getting any more of it. It seems like it needs to cure at a lot higher of a tepm.
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Just an FYI. I have heard from someone else that they are having the same problem as you with that white. I have some of it too but I have not had that issue yet. I wont be getting any more of it. It seems like it needs to cure at a lot higher of a tepm.
I think that too. I was told from a salesperson that it is overcured :o
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Bull poo.......lol
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from what I am seeing, that looks undercured to me. 25-30 sec in the dryer is not the measurement, it is how long is it at temperature. Get your temp gun and see how long is the shirt in there and above 300 deg. If it is only a sec or two, you will need to slow down your belt. If they are getting out at 380 right now, they might be even hotter when slower, so I would drop the temp too so they are still getting out at 375 or so. I know that is hot and you will have problems with 50/50's but for most jobs, I would imagine it should do. For bleeders, you might have to slow down and drop the temp even more.
pierre
I realized what you were asking (I was tired that day).
I measure the temp about foot inside the dryer, it was around 360-370. It takes a good 5-6 seconds before they exit the dryer. I can not measure deeper in the dryer due to the tight opening on the exit. I think that the cure temp is OK, unless my temp gun is completely out of whack.
I will try again with different temp gun or a donut probe if I manage to go to Lakewood to see Sparkie.
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Hers the thing about temp guns. I do not know what one you have but if its one from home depot its probably off. I have one that I paid around 140.00 bucks for that is dead on. My buddy runs an aerospace company that use ones that cost thousands of dollars and have to be calibrated regularly. He took my good one and one I bought at Home depot for 30 bucks bucks and tested them. The Ryobi one from HD was inconsistent and and read anywhere from 20-40 degrees less. My good one was within 5 degrees either way every time. It is also important to keep a good battery in it as that will affect its readings as well. Just an FYI in case yours is off.
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Sorry to bring up an old topic, but how long do you typically have the shirt in the dryer for the ink to cure? I've been told it needs to be in for at least a minute???
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I like to have them in there for a full minute. That might be longer than necessary but I'd rather err on the side of too long than too short. If you bring the temperature quickly up to cure temp and then quickly back down (short dryer time), it may still be undercured. It needs to remain at full cure temp for a little while to cure all the way through.
Also, as others said, the edges of a print will not reach the temperature that the center does. Many people make the mistake of taking the temperature reading only in the center and assuming it's the same on the edges.
I like to cure my ink on the hot side too, just to be sure. When you're running a lot of shirts through one after another, your dryer will cool off because the shirts carry the heat out of the tunnel. I've never experienced "overcuring", even when I've baked the living daylights out of a print. I think the shirt would scorch before this happened.
You should be able to stretch a fully cured print hard without any cracking, unless the cracking is caused by a thin ink layer rather than an undercure.
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and what white would that be that everyone was raving about.. i think i missed that white of the week.. :)
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Which $150 IR gun are you using, post link if possible. Thanks
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Which $150 IR gun are you using, post link if possible. Thanks
Pretty old thread to hope to get JBLUE to see and respond (depending on how he has his notifications set up)
I don't know what gun he has, but here's an example of a step up
https://www.amazon.com/Fluke-Infrared-Thermometer-Degree-Range/dp/B01N9W6P54 (https://www.amazon.com/Fluke-Infrared-Thermometer-Degree-Range/dp/B01N9W6P54)
Or for a little less https://www.amazon.com/Fluke-62-Infrared-Thermometer-Series/dp/B00U4EP04I (https://www.amazon.com/Fluke-62-Infrared-Thermometer-Series/dp/B00U4EP04I)