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Hi all! I'm wanting to get back into screeprinting with water based ink. I previously cured my water based ink with a tunnel dryer. I sold everything a few years back and I am re-starting in a much smaller space. I plan to use a flash dryer to DRY my shirts, and I will add a cold cure additive so it doesn't need to reach any specific temp just need to get it dry to the touch. How long will my shirt need to sit under the flash dryer to DRY the ink? Thanks!!
 

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Due to space limitations, I've never had a tunnel dryer. I've always used a heat press for curing water based inks. Takes up little space and is not expensive compared to a tunnel dryer. I press for one minute at 340 F if using Permaset inks, more like two minutes if using Green Galaxy or Matsui. I haven't bothered to do thorough testing to determine the minimum that I could get away with, which obviously I should do as the time to do the testing would be recouped many times over.

Since a heat press makes physical contact with the ink/garment it transfers heat via conduction. So if the heat platen reads 340 F, then 340 F is then put in direct physical contact with the ink, no more and no less. As opposed to any type of radiant heat source, where the emitter itself is much hotter than the temperature you want the ink to reach, so distance and time become critical to avoid scorching, as well as undercuring. Point being, curing with a heat press is less fussy and error prone than using a radiant heat source.

No need to apply a lot of pressure, as all that matters is that even contact is made with the print area of the garment. I lay the garment on top of a Teflon heat press pillow thingy so that collars and seams and such don't interfere with making even contact.

A downside of cold cure additive is that it starts a clock ticking on the ink, so it must be used or tossed out within a certain period of time.

Apologies :eek: I know it's not the question you asked, but perhaps an option to consider. Testing is the only way to answer your actual question.
 

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How long will my shirt need to sit under the flash dryer to DRY the ink?
That's like asking how long it takes for water to boil.
The same apply to ink.
It depends on the equipment you use and the amount of water.

If you print long runs, you can optimize temperature and time to save time.
Otherwise, simply dry them long enough to dry the heaviest print.
 

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That's like asking how long it takes for water to boil.
The same apply to ink.
It depends on the equipment you use and the amount of water.

If you print long runs, you can optimize temperature and time to save time.
Otherwise, simply dry them long enough to dry the heaviest print.
Having cured many a water based prints on cotton, forced air is your friend the heat of the flash dryer by itself heats the ink by does not completely remove the water unless you have an Air Flash I always used a flash dryer 3” above the garment and used a 1500 watt hair dryer to remove the steam/water Vapor from the garment (this is why you need a long conveyor dryer with lots of airflow to remove the water from the ink and set the soft pigment on the garment) I have tried the heat press method which will work but you really need lots of airflow to do water base or discharge consistently and effectively. RFU H2O (ready for use water based inks) set at 285-305 degrees Fahrenheit but only if water has been removed this is particularly important when doing discharge printing on darks as you need to remove the formaldehyde with airflow then activate and set pigment with heat (discharge printers know the odors emitted). Hope this helps. Try curing shirt with flash only then try one with flash and hairdryer blowing over garment, when using humidity checker the flash only still has a higher moisture content which is less than ideal a low cost solution or if your girlfriend/spouse asks have you seen my hair dryer? A worthy cau$e!
 
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