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screen printing => General Screen Printing => Topic started by: Itsa Little CrOoked on May 08, 2015, 01:01:33 PM
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Yes. I meant closet. I've been putting my screens in a 4'X4' closet with an 8 foot ceiling. The racks are mounted to the walls. (It used to be okay, but its really too small now. I'm just out of space.)
All that room is, is UNexposed screen storage. I process them elsewhere.
Anyways, my Peltier style mini dehumidifier has finally croaked, and I replaced it with a proper, 30 pint per day, GE compressor style. The room is a little too small for the amount of heat it generates. OH ITS DRY IN THERE ALRIGHT!!!....but its also 99 degrees.
I figure 99° is okay for now. But NOT in a typical Kansas AUGUST....
Anybody know the answer?? I'm all Diazo right now, if that matters.
Thanks!
Stan
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104 is what I often see as the max drying temp on tech sheets for both Diazo and Photopolymer
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Thanks Andy, and it occurred to me to call Richard Greaves AFTER I posted this question.
104º has been proven to flub up stencils, so saith The Greavester. You and he are in agreement.
Additionally 99º is too close for comfort.
I use 2 (two) separate combination hygrometer/thermometer units from Walmart, http://www.walmart.com/ip/16888914?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227009373117&wl0=&wl1=g&wl2=c&wl3=43538542352&wl4=&wl5=pla&wl6=83259689792&veh=sem (http://www.walmart.com/ip/16888914?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227009373117&wl0=&wl1=g&wl2=c&wl3=43538542352&wl4=&wl5=pla&wl6=83259689792&veh=sem) 9 bucks and the both completely agree on the RH and Temp. Amazing
"THAT'S HOW I'M MEASURING", Richard. (Apologies if you don't "get" that. Richard will....)
I'm going to try to cycle the thing with a digital timer. My unit "remembers" after power failures, so it could work. The included settings on the actual panel stop @ 35% and below that, the setting is CO (for continuous) and that does produce some ridiculously dry air. And, of course, lots of heat.
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My screen room is basically a glorified drying cabinet with my FPU and coating station in it. I have a 40 pint dehumidifier in it and a 20 inch oscillating fan for airflow and drying. The room is roughly 7x9 with 8 foot ceilings. I found that it DEFINITELY got too hot with the humidifier in Central Texas summer months. I grabbed a $20 5000btu window A/C and cut a hole in one wall and tossed it in. I keep my room at around 82 degrees and 35% humidity year round. It is an internal room and has insulation on all walls and the ceiling, and the door and cutout for the A/C have weatherproofing. I have racks that hold 25 screens in two of the corners and a rolling cart that holds another 25 between them. The most I usually coat at once is 25 or so, and it will dry a full 25 in less than an hour. If I turn off the oscillation on the fan and only coat a handful they can dry in about 20 minutes.
I built the room specifically because my drying cabinet got too hot during the summer since it had no insulation and no A/C and I definitely had emulsion heat set on occasion.
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My 8x8 drying room (with 1500w heater and dehumidifier) varies between 95ish and 110ish, depending on volume and how frequently the door is opened. I've never had any problems with that. It's bone dry in there (sometimes in the low single digits on slow days).
I try to not keep screens in there to dry after coat longer than necessary...but sometimes they'll be in there for hours at 110ish with no problems. Photopolymer + diazo.
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Went the dehumidifier out. Connect the exhaust and went it outside the room. That way all the heat and humidity is taken outside the room.
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Thanks Andy, and it occurred to me to call Richard Greaves AFTER I posted this question.
104º has been proven to flub up stencils, so saith The Greavester. You and he are in agreement.
Richard is one of those industry stalwarts with whom, I believe, I have never had a disagreement. I can not say if he can say the same about me. :D
Wait wait, there was a time when I brought up an old screen police article about scooping emulsion back into the container.
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We have a really old screen dryer, we run it around 105°
Steve
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We try to keep it in a range of 36-40 degrees Celsius.
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Basicly want to keep the temps below 90.
Heat doesnt dry screens, removing the moisture does.
Use as small of a dehumidifier as needed. A 30 pint can handle an entire house delending on your location. The more sealed up the room is, the better.
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Hey...we're not baking cakes here. (https://www.chromaline.com/wp-content/uploads/2012/08/ta_howtodry.pdf)
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Richard is one of those industry stalwarts with whom, I believe, I have never had a disagreement. I can not say if he can say the same about me. :D
Wait wait, there was a time when I brought up an old screen police article about scooping emulsion back into the container.
I pretty much always scoop the remaining emulsion back into the container. I try to avoid the partially dried "bits" however.
I've been "bitten" by the practice, but rarely. If I were doing much high end stuff, I might stop doing it.
Thanks for all the replies, but I might just clarify my situation. I'm drying my emulsion AND storing the screens in the same closet. My old Eva-Dry 2200 was a Peltier-style dehumidifier which added very little heat to the area. When it died, I bought a GE ADEL30LR 30 pint compressor/condenser/evaporator style which, although removes more moisture, adds MUCH MUCH more heat from the condenser. Although I knew that was going to happen thought I could get away with it.
Wrongo...
If I could expel the exhaust air from the condenser outside the room, I'll be in tall cotton...because the little bugger can pull the room into the low 20º RH area during a rainstorm. But I lease my building, and I don't want to pony up to "fix" the closet, unless I can't outsmart this otherwise.
I might be able to exhaust through the door somehow, then just put a grille in the hole if/when we relocate. I'd have to mount the unit ON the door--I think--and the Fire Marshall would probably give me The Stink Eye with a corded 120V appliance mounted on a wooden door.
Still thinkulating on this.