Exactly how long does plastisol have to remain at 330 degrees to cure?

[Frog]

instantaneously once the entire deposit reaches it's cure temp.  Plastisol doesn't have to be at a certain temperature for a length of time, just has to reach that temp that it was made to cure at.  Most plastisol inks these days cure at a lower temp than 330.

That blanket statement is kind of like saying all screenprinters are aging, ponytailed, balding, wanna be hippies, who bootleg tye-dyed Deadhead shirts in the parking lot before they get stoned at a GD concert.  While it may be true in many instances, there are exceptions.

The plastisol ink guys should chime in here but some of the 'newer' plasticizers require being "held at cure temp" to allow complete conversion to washfast solids.

Ink guys where are you.....

I believe that, newer plasticizers notwithstanding, the statement may well still be accurate, as it still takes however long that it takes the entire layer of any particular plastisol ink and its particular plastcizers to reach cure temp.

When companies like QCM specified (or recommended) a specific dwell time, it was merely to help ensure cure.

Where's Richard Labov now that I need him? RIP.

[3Deep]

This is a good thread it's almost like which came first the chicken or the egg, but the big question is how long does it take your dryer to cure plastisol in your shop.  I can only tell you what it takes in my shop and the results I get, I'm willing to bet two dryers exactly alike will dry different even in the same shop.  Then the question ask does not specified a type of dryer being used or how big is the heat chamber, I think all this plays a big roll in the answer, which might be different on whatever equipment you are using, now my answer to the question goes like this, I use an Econo Max dryer (older model) 8 ft with 2 ft heat chamber running at 1000dg which gets the shirt to 340 to 350 degree.... a 35 to 45 second shirt dwell time would be my answer.

Darryl

[ZooCity]

We installed a TexAir with 10' of heat a year or two ago.  We used to run WB through it and plastisol through a short Vastex, manual printing. We now run all our prints through it- plastisol, WB, DC -on the same settings for WB since the day is a mix of all those inks typically.  I can't recall the chamber time off the top of my head but it's very long by comparison.

The Wilflex Epic plasti we print with is absolutely, beyond any shadow of a doubt, a better finished product when cured in this fashion.  It is true of all the various Epic inks so far but especially true of the Quick White. They feel great- super soft and pliable with a nice matte finish and adhesion appears to be excellent. 

I discovered this one day when I bugged out to see the temp on the heat gun at 340˚F at the back.  I thought for sure we were under curing since 360˚ used to be our safety line with the short dryer.  Remember, a non-contact pyrometer is reading a cone of air with it's round base on the shirt so this is all relative.  Actual donut probe temps are wildly different- 360˚ laser gun ≈ 320˚ on the atkins probe.

Anyways, my printer insists that the shirts are curing fully at this temp.  Hmmm...they do pass a stretch test.  I skeptically tell her to wait on shipping out this order and wash test.  It's perfectly cured and feels way, I mean seriously much, much better than a print that was "zapped" up to cure temp. Our dryer is slowly lifting the entire garment up to temp (forced, hot air knives in the middle help a lot here) and holding it there for a longer time.  This allows for a lower surface temp reading and is doing something to that ink film that a shorter, hotter trip is not.  I think owners of gas dryers know this feeling perhaps.

Just my experience.  I am no longer hearing arguments that "the newer IR panels have a better wavelength" and "you can zap this ink up to cure temp as rapidly as you like, it just has to to hit (insert magic number)" and get the same quality of the finished print.  Will it still be "cured" if you rapidly bring the heat up to xxx˚?  Sure, but it won't be optimally cured.  I'll bet anyone a shiny eisenhower dime that any data out there would confirm this, at least with the the Epic line of inks.

[Frog]

One thing is for sure, overheating tends to make the surface glossy, so right there is a good argument for slow and steady, but that was not the question.

[ebscreen]

My experience with my first gas dryer has been exactly what you've described Zoo. The lower
readings at the back of the dryer are fine because with circulated air and particularly gas heated
circulated air the whole garment is at that temperature, as opposed to straight IR beating down
from above. We run everything except poly/blends at the same temp/speeds, low and slow.

[ZooCity]

My thoughts exactly, it's more of an oven than a toaster.