TSB
screen printing => Equipment => Topic started by: rusty on February 22, 2018, 12:55:33 PM
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Hey, I am curious to how forced air works, particular in the case of electric dryers. I have two small vastex electric dryers and I am planning on combining them. was wondering if I could make a forced air tunnel in between the heating elements. Is this possible?
Just to get it out of the way, I can't put a gas dryer in my location and I have yet to find a good used electric near me that could handle water base/discharge printing.
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The ones I'm familiar with have an open channel on the top and fans at either end that circulate the air across the top.
I found forced air did not help at all with WB cure speed, in fact turning it off sped it up a bit.
I would think you'd probably be better off retrofitting another panel in between and fabbing a decent cover?
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I believe that Vastex emphasises exhaust as being key to the evaporation that water base needs.
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yeah, I've been looking blower fans to have in the channel between the heating elements. Going to read up on it this weekend. Was hoping someone had a "for dummies" explanation.
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If you are not evacuating a significant amount of air you are doing nothing but making a sauna inside your oven when running water base. Ie you probably have a fan in your screen room which is doing nothing but moving huge amounts of air that is lower in humidity than the screen surface.
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Interestingly Vastex didn't persevere with the forced air in their small dryers. I recall it being offered for a short time, but yes, a very short lifespan and I don't believe it's offered any longer.
I'd say that's quite telling alone.
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From what I have been reading it seems I would need a fan below the tunnel bringing fresh air in and another exhausting the hot air out above. I could be wrong, theres only so much info I could out there for this type of dryer. My eyes starting going crosseyed going down this rabbit hole.
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We have an 8' Lawson Encore with forced air. Implementation is pretty basic: There's an intake port at the top of the dryer, above the heating elements. Air is pulled from there by a fan, and blasted downward through a metal box full of small holes, just before the shirt exits the dryer. From my experience, it seems to even out temps in the dryer somewhat, maybe making it a little less likely to scorch under the elements. But it doesn't seem to make a huge difference. However, that's with plastisol. We don't currently do WB, and I wouldn't consider this an adequate solution for decent production rates from a manual press. The larger Encores appear to have 2 air curtains, with one being farther back in the dryer. I suppose it's possible with more air & more tunnel time, this might be acceptable for WB curing, though I'd still expect modest production rates.
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From what I have been reading it seems I would need a fan below the tunnel bringing fresh air in and another exhausting the hot air out above. I could be wrong, theres only so much info I could out there for this type of dryer. My eyes starting going crosseyed going down this rabbit hole.
Might help, but the older unit I'm using actually recirculates the air. It's a balancing act, because if you exhaust air very quickly you can evaporate water quickly, but then it becomes difficult to heat to cure temp.
I think the issue with WB/DC and the recirculating style is what T shirt farmer mentioned, circulating humid air doesn't help evap much.
I'd guess most electric dryers aren't even close to being overpowered enough to exhaust much more wet air and keep temp.
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I have a Vastex EconoRed with scrub air blower, we use it just to speed up the cool down before we go home ::)
mooseman