Flash Dryer - essential??

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DarkFairy
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Flash Dryer - essential??

Post by DarkFairy »

Hi :) , I was just wondering if you need a flash dryer?
Do inks dry on their own if you left them over night?

Also, what wattage is a normal flash dryer?

Thanks
ftembroidery
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Post by ftembroidery »

There ARE air-dry inks for textile decorating, but nearly all the decorating you see is plastisol. Plastisol must be heat cured. Most plastisols cure after a few moments (called dwell time) at around 320ºF (some slightly higher, some slightly lower). A "flash dryer" is used to "gel" the surface of a layer of ink (this will often occur when the surface of the ink reaches around 250-275ºF). After the "gelled" or "flashed" ink has cooled, another layer or coat of ink is applied. This is done when the ink is not sufficiently opaque with only a single coat, and the shirt color can be seen through the ink (such as when putting white ink on a black shirt).

Obviously heat is heat so a flash dryer CAN be used to fully cure the plastisol, but it is not recommended nor is it efficient. Flash dryers are very susceptible to drafts, and may not be as effective toward the outer edges of the platen upon which the shirt is placed. Also platens on the press are not designed to be used as full-cure stations and will warp and become damaged by long-term applications of heat. If you absolutely have to use a flash dryer for fully curing the plastisol, get a platform of some type that WILL withstand the effects of long-term heat, set it up so it is the same height as the platen on your press and when you are ready to fully cure your shirt, place the shirt on that platform and rotate the flash dryer over the shirt.
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DarkFairy
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home made flash dryer, infrared bulbs

Post by DarkFairy »

Hi, thanks for responding.

If flash dryers are inefficient, what other methods can be used to cure plastisol ink? (I know about conveyor dryers, but they're a bit 'industrial' for my needs)
I've seen a couple of people talking about oven curing, but that seems a bit risky to me?

Edit:
If flash dryers use infrared, my dad (who's an electrician) could make me one, with infrared bulbs - I can get 250w ones.
I was just wondering if this is doable, and if any one knows how much heat a 250w bulb would put out? I could use more than one bulb if it isn't enough.

Thanks again.
ftembroidery
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Post by ftembroidery »

In the screen printing industry, there are dryers that are conveyor-belt type "ovens" (you may have seen something similar at your local pizza parlor). Those are the way to go. OTHERWISE,...you might find a used kitchen oven (I'd recommend electric over gas) that you could hook up and "bake" your shirts for several minutes in at about 320ºF. The reason I say "several minutes" is, a cooking oven heats the air within the oven and by convection, over a period of time, anything within the oven become hot as well. In other words, the heat from the air has to "soak into" the item being baked.

The type of dryers used in screen printing are mostly Infra-Red panels within a heat tunnel. The Infra-Red (IR) panels emit wavelengths that heat "THINGS" not air. The air or area within the heat tunnel does get hot, but that's because everything that makes up the heat tunnel has gotten heated by the IR waves and that heat is just radiating back off. That's why the shirts going through the conveyor dryer don't need to be in there for very long.

I have heard of people curing their prints with a heat gun (hi-performance hair dryer type of device), but that would obviously be even less efficient than using a flash dryer.
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