I'm about to build a drying cabinet for my new shop. I've already worked out my plans but I've read a lot of discussion about the drying system people recommend. Some people say forced air, others heat, and some say dehumdifier.
I already have a small heater that I used at my old shop in a very makeshift sort of way. But I'm very curious about the dehumidifier. If it works as well as I read, I'm all for it. Anyone have some details on the differences between these different methods?
I've also heard of using a shop vac to suck up extra water after degreasing the screen but before putting them in a drying cabinet. Anyone know anything about that?
I would say it depends on how fast your wanting to dry your screens. A dehumidifier will remove all the moisture out of the air which in my experience will be the fasted all around.
Using forced air to blow out the excess water in the screen after reclaiming as well as burning will help to speed up the process.
Heating, is not drying. Dry air will suck the moisture out of the stencil. Heat will expand the air around the stencil, decreasing the relative humidity, and then the air will suck the moisture out of the stencil. Mother nature hates imbalance.
A wet-dry vacuum requires a special very thin opening in the tip to pull EXCESS water off the mesh and stencil. It is always a good idea to remove excess water which saves time evaporating it.
Beware the dangers of forced air, because it usually has oil in it and can do some damage. If that's all you have, use it, but it doesn't cover as much area as newspaper to blot, or the special vacuum tip.
__________________
How are you measuring? retired Ulano Technical Support Screen printing since 1979 - SGIA Academy Member
Last edited by RichardGreaves; August 13th, 2007 at 09:32 PM.
I have a home-built drying cabinet that uses a dehumidifier. It not only "sucks up" moisture, it heats the air so as to get the moisture INTO the air (as Richard Greaves said, "mother nature hates an imbalance") so it can remove the moisture. It works VERY well. The only "difficulty" is, it seems dehumidifiers come in a variety of sizes that range from way too small to way too big. My dehumidifier is about 18" tall by 12"wide by 8" thick. (I'm working from memory here). The next size down wouldn't be big enough to do any good. I equated it to the difference between a battery charger that only "trickles" enough energy to keep a rarely used motorcycle battery charged and a larger but not "professional auto shop" sized battery charger. I recommend the dehumidifier route.
I would say it depends on how fast your wanting to dry your screens.
I'm shooting for around a 20-30 minute dry time for a cabinet that can hold up to 12 screens. Obviously a full cabinet of wet screens will increase the dry time but typically I only do around 6 screens at once.
Dehumidifiers are rated by the amount of water they'll remove in 24 hours....if you decide that 12 screens hold a total of 1 quart of water, and you want them dry in half an hour, you'll need a dehumidifier rated at 48 quarts.
Thanks for the info. I'm going tomorrow morning to purchase my materials. I'll see what they have for dehumidifiers. Worst case senario, I may purchase 2 smaller units since there will be enough room in the bottom of my cabinet.
Hey all....Will anyone be willing to share their schematics of a homemade drying cabinet? If you could at least point me in the right direction that would be a big help. Thank you much for your time.
Well, I got the cabinet together and ran a few test screens through it. Everything seems to work fine. I built it to hold 9 screens instead of 12. I found a 30 pint dehumidifier that managed to dry a handful of soaking wet screens in around 35 minutes. The light manages to stay out as well. For never building a cabinet in my life I must say I'm quite proud of myself.
Quote:
Originally Posted by Newcomb Graphix
Hey all....Will anyone be willing to share their schematics of a homemade drying cabinet? If you could at least point me in the right direction that would be a big help. Thank you much for your time.
Sadly, I keep all of my schematics in my head and a handful of measurements on paper. But if I get time over the weekend I'll see what I can do to give you an idea of what I worked with.
Ok, here is a rough layout of the cabinet I built. The measurements are not precise since most 2x4s are acutally 1 1/2" thick. That threw me off a little but hopefully this will help point other people in the right direction.
This Cabinet can hold 9 screens that are 20x24. Originally I wanted 12 but the only dehumidifier I could get took up the place of 3 screens. I've been using it daily since I built it and it works great. My exposure unit fits right on top too.
The best part is that they forgot to charge me for any of the plywood I bought. The whole project cost me $220 and that includes the brand new 30 pint dehumidifier and all other parts.
It took 1 full day to construct but that's because I did it all myself. The friend that was supposed to help me pulled a Houdini after 30 minutes and vanished.
I use one of these to air dry. It is a blower, not a compressor, so no issues with oil. It moves enough air to completely dry a screen in less than a minute. I let them dry in the rack for another 30 minutes before using them.
I suspect you are all refering to drying time for pre-emulsion-coated screens, right?
I have been trying to get a good idea of the total drying time for 20x24" screens ranging from 110 to 156 mesh count; i.e drying time after degreasing + drying time after emulsion is applied.
Can anyone give me an idea? I would definitely like to give the homeade drying cabinet a shot because i guess the alternative is to use a full day & night letting everything air dry??
I have been trying to get a good idea of the total drying time for 20x24" screens ranging from 110 to 156 mesh count; i.e drying time after degreasing + drying time after emulsion is applied.
What kind of emulsion are you using?
Right now I am using a dual cure liquid emulsion so my degrease and emulsion are 2 different drying steps. Typically if I am drying 4-5 screens at once, the dry time is between 20-30 minutes for each step. If I fill the cabinet with wet screens (around 10 screens) the dry time is will run around 30-45 minutes to dry all the screens.
If you are using the sheets of emulsion (I can't think of the name right now) you can cut your drying time in half since that can be done as one step.
Homemade Drying Cabinet 
