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screen printing => Screen Making => Topic started by: Appstro on January 15, 2014, 02:15:06 PM
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OK so Sunday I built my drying cabinet out of wood. Its light proof and looks great. I am ready to coat the clean screens with emulsion and stick them in the cabinet, but since the cabinet has no fan or dehumidifier yet, will I have problems with the screens drying overnight? The cabinet only holds 9 screens so it will probably be pretty humid in there for a little while… Will my screens turn out OK?
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there is only one way to find out, but my guess is no...also where are you located? if the air is dry you have a better chance.
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San Diego
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Pick up a very small fan and a pellet dehumidifier (It's better than nothing). It will at the very least be good to have in there and speed things up.
But, I am betting your screens will take a while to evaporate/dry sufficiently since they are in a small enclosed space.
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Put the "fart fan" on the top and a few holes on the bottom with a some kind of filter on them.
That will make the air move through
http://www.homedepot.com/p/Broan-70-CFM-Ceiling-Wall-Exhaust-Fan-671/202905936# (http://www.homedepot.com/p/Broan-70-CFM-Ceiling-Wall-Exhaust-Fan-671/202905936#)
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I coat mine in the evening and they are ready next afternoon
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Thats a great idea! I was planning to use a computer fan with a filter. I havent quite figured out how to set it up so that the fan is pulling out air and the box stays filtered and dry yet. I didnt leave enough space inside for anything but the screens, really.
I dont mind waiting a day or two for drying as long as the quality of the screens will not be effected. For now anyway…Do you think they will turn out OK?
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If you use an exhaust fan for a bathroom that shouldn't take up much space... no more than a screen's worth.
I will eventually have to plumb my dehumidifier into my cabinet because it takes up MANY screens worth of space. :(
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In my home-made drying cabinet, I have a dehumidifier on the floor and a box fan at the top. While cleaning fan a few weeks back, I tried coating without it in the cabinet...everything except for my coarsest mesh (61) came out fine...the 61's had emulsion drips (think blunt stalactites) dried into the underside of the emulsion, unuseable. Give it a try with one or two of all mesh ranges and see what happens. My guess is, without dehumidification or moving air, you are going to have trouble.
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A computer fan will not be sufficient to move that much moisture and you would want the fan mounted at the bottom and the exhaut at the top..
http://youtube.com/watch?v=NhQojYudUW8
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Put the "fart fan" on the top and a few holes on the bottom with a some kind of filter on them.
That will make the air move through
[url]http://www.homedepot.com/p/Broan-70-CFM-Ceiling-Wall-Exhaust-Fan-671/202905936#[/url] ([url]http://www.homedepot.com/p/Broan-70-CFM-Ceiling-Wall-Exhaust-Fan-671/202905936#[/url])
Thusly:
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To avoid said stalactites, I'd suggest a fan outside the cabinet to "skin" them over and then putting them in the cabinet.
This is what I did before I built my cabinet.
Not elegant, but it worked.
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Yep, you need air movement to evaporate solvents in the emulsion, or anything else for that matter. We have screen dryer, but before I did, I simply used racks and a fan in a light safe (yellow tubes on fluorescent lights) area. Then, we store dried screens in a dehumidified cabinet. Not a big deal at this time of year in Massachusetts, but during the summer, when it's super muggy, it's a necessity.
Steve
I haven't used 61 mesh for a long time, give Saati's 81SDE for a really pleasant surprise; basically an 81 with 110 threads, ink lays down very nicely.
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A good read is "factors affecting the rate of evaporation"
http://en.m.wikipedia.org/wiki/Evaporation
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small fan is what we use , usually coat after everyones gone then leave door open on cabinet with fan blowing over the screens through the night. There always ready in the morning . The fan we use is just a small 8" one set on low. If i don't have the fan on they don't well and drips occur.
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Gotcha! I have the cabinet door open now and the floor fan on low. Wanna hear something funny though? I blacked out the shop and found the perfect spot for my cabinet. When I turned all the lights off I saw a flickering light coming from the roof of the shop....shining right on the spot where the cabinet is..... Its a stupid dormer whirly bird thing. had to climb up on the roof and put a few trash bags over it for now to block the light!!!
Screens drying now :)
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Looking at the screens as they are almost dry....The emulsion seems thin. I coated 1/1....made sure I had full contact with the coater....Should I be feeling and seeing the mesh on the screens?
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Put the "fart fan" on the top and a few holes on the bottom with a some kind of filter on them.
That will make the air move through
[url]http://www.homedepot.com/p/Broan-70-CFM-Ceiling-Wall-Exhaust-Fan-671/202905936#[/url] ([url]http://www.homedepot.com/p/Broan-70-CFM-Ceiling-Wall-Exhaust-Fan-671/202905936#[/url])
Yeah, that's what we did:
1st photo is hepa filter over air intake side, second photo shows fart fan that sucks air out of the cabinet, third photo shows holes between the two sides for air-flow.
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What about the light that gets through the fart fan?
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Looking at the screens as they are almost dry....The emulsion seems thin. I coated 1/1....made sure I had full contact with the coater....Should I be feeling and seeing the mesh on the screens?
Not with a proper glisten method.
What about the light that gets through the fart fan?
Unless it's something more than basic fluorescent or home lighting then I wouldn't worry about it. Now if you have a window blasting on that vent then I'd do something.
It's been discussed a good bit about the need to go crazy with UV protection. The general consensus seemed to be that it was fairly overrated.
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It was 85 degrees in the Sandy Eggo today.. and about 28% humidity.
Around here, all we really need is a fan to move the air.
Man.. I love San Diego this time of year 8)
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there are shops around me that still use red lights in their darkrooms. we are moving to regular light, LED's to be exact. We are testing right now to see if they will expose a screen overnight or over a weekend. I am thinking no, but we'll see....a poor man's uv tester.
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Those are some nice cabinets, but mine is a small one that I sit a fan in front of and screens are dry in about 15 to 30 minutes at least to my touch and they seem to burn fine with no problem.
Darryl
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I used a fan last night, but see that I should have vacuumed out my cabinet before placing the screens! A few wood chips.....I just built it Sunday, but got in a rush,...
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That's why sucking air out is better than blowing air in, unless you go full on clean-room style with positive pressure, filtered air.
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Ink you make a good point, I know I get dust on my wet screens before they dry cause of the fan blowing on them, but it has not been a problem causing pin holes. I've been telling myself I was going to build a nice dryer cabinet one day...that one day just hadn't got here yet.
Darryl
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If you're using yellow mesh, you can cut a small scrap of that to use as your fan filter, & it will also help filter light. I'd use 230 or thereabouts. -- that should catch most lint, but still allow some air through.
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Thats a good idea. I am probably going to to the "fan upgrade" this weekend :)
I am itching to make some shirts today :)
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That's why sucking air out is better than blowing air in, unless you go full on clean-room style with positive pressure, filtered air.
Remember though that that's exactly how a vacuum cleaner works, and without some filtering, the cabinet becomes the vacuum canister or bag!
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Lol, yeah I hadn't thought of it that way. We always found when we were just using a box fan, that blowing it into the cabinet raised dust, where sucking air out was much gentler and worked just as fast. Actual clean rooms work exactly the opposite, and any small spot where air can leak will have filtered air coming out of it, rather than sucking air, and contaminants into it. Eventually we'll have a small fan blowing filtered air into our screen room for this exact reason. Done right the room should stay quite dust/lint free.