Curing ink

[Denis Kolar]

I have some shirts that with in on them that is not completely cured (I think). Could I run them trough the dryer again?
The shirts have been sitting like that for about 10-15 days. Is it too late?

Also, now instead of looking for a 320-340 degrees on the dryer exit, I'm looking to read about 360-370 with my spot IR temp gun.

Thanks

[Northland]

Plastisol... ?
It should work to send them thru again.
-or- heat press them.

[Denis Kolar]

Yes, it is plastisol.
No heat press available   But looking to buy one soon.

Thanks

[Fresh Baked Printing]

Plastisol will stay uncured forever until brought to proper temp. Run them through again.

[Frog]

Plastisol will stay uncured forever until brought to proper temp. Run them through again.

I'd say that could be a negatory if not at least partially cured, as the fabric could leach out plasticizers from the ink.
Maybe Erin or Colin could add to this.

As for DK's, I'd say no problemo. However, it is not a cumulative effect. It just needs to reach cure temp all the way through.
And yes, 320 is way low for that already merely representative reading.

I see temps at around 370-380 a split second before exit, as well as a hint of vapor as some here have mentioned as well.

Get ready for the donut probe fans to chime in here.

btw someone on the old board, made his own weighted probe. Maybe we need a no-prize DIY contest for the thrifty (or cheap)

[squeegee]

 I had a small order returned last summer for undercured ink. I put the shirts back through the dryer and the washed tested both a previously washed shirt and and unwashed shirt from the same batch.  After recuring they washed fine, even one of the shirts that had cracked ink pretty much stayed the same after that.

I found out later my guys were speeding up the dryer belt to get their sample prints out and approved fast and most likely forgot to set the belt back to normal on this job.  We don't do that anymore.

But yea the donut probe is a great tool, I've found our IR gun shows different temps than the probe, usually higher.  After a shitty experience a migration issue a few weeks ago, I've been compiling dryer settings for all kinds of garments/ink combinations.  We're seeing the benefits now, nearly no scortching or overheating of ink film and peace of mind knowing everything is cured correctly.  The probes are spendy but nothing is more accurate as far as I know.

[Fresh Baked Printing]

IR guns show different temps at different distances and different angles. Not the most accurate but good enough for me.
For heat press stuff, my heat press temp gauge isn't too accurate. My heat press must be 20 years old. Ugly and rusty components, but man, that thing is built like a tank and is solid! I think it's a Hix heat press.
For the heat press, I wedge a turkey temp probe to the plates then to the platen for a test press so I get true touch readings.

BTW, those donut probes are'nt cheap? http://estore.lawsonsp.com/atkinsdigitalthermometer-digitaltemperaturemeasuring.aspx

[ErinAllenLamb]

You should be able to run it back through the dryer and as long as the entire ink film hits the cure temperature it should be good. As always, do a wash test to ensure it is cured!

Look into a thermoprobe. It is the most accurate way to measure the temperature of your dryer!

[Colin]

To add to what has been posted on "after curing".

Whether or not you can properly curing an ink days or weeks later is directly dependent on the amount of plastisizer left in the ink.  If the ink is barely flashed, the cotton threads (cotton being highly absorbent) have a greater chance of leaching away the remaining plasticisers.  Now, it's not going to pull away much, since the great majority is bound up with the resins, but it can still come into play when you go back to finish the cure stage.  And this can have an impact on how well the ink cures and adheres/stretches with the garment.  Overall, you should be fine.

The same concept can happen with plastisol transfers.  For those of you who have transfers sitting around, you may have noticed the older transfers have a chance of getting a "halo" around the edges.  This will happen when the ink is not completely gelled properly.  The paper, again, is absorbent and will leach away the plastisicers in the ink.  This is one of the reasons why older transfers will have a greater chance to fail when used.

Also, I just want to touch on one aspect of properly curing the ink layer.

While it is true, that once an ENTIRE ink layer reaches fusion temperature, it is cured.  The longer that ink is at fusion temp the better it's adhesive and abrasion resistance properties are.  Also, you will see improved stretch characteristics compared to the same inks that "just" reaches full cure temp. 

So if you take two shirts that were printed exactly the same, keep one at cure temp for say 30 seconds longer, you will find that after repeated washings the one that was cured for a longer period of time looks better with fewer cracks and appears brighter (depending on design and inks used).

[ebscreen]

Awesome info Colin, thanks for that. I had no idea about
the dwell time being beneficial. Luckily I run my dryer slower and
colder for almost everything.