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Screen Drying

Posted on Sat, 15 Feb 2003 at 14:45



I know screen emulsion is sensitive to heat. My question is, HOW SENSITIVE? Can I dry my coated or store my dried, coated screens in an area that can get up to 100 degrees (my garage in the central valley in california-Whew! HOT).

Thanks
Steve

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Anonymous says: Hi Steve: How to Dry a Screen second page under Drying coated screens: "Temperature Emulsion manufacturers typically recommend drying coated screens at a temperature around 110°F (40°C) because higher ...

Hi Steve:

How to Dry a Screen second page under Drying coated screens:
"Temperature Emulsion manufacturers typically recommend drying coated screens at a temperature around 110°F (40°C) because higher temperatures can have an adverse effect on stencil performance (for proof, see the sidebar "The Impact of Heat on Stencils" on page 43). All diazo-based emulsions are sensitive to heat. In fact, any temperature above freezing will start the decay of the diazo sensitizer in the emulsion (this sensitizer allows the coating to cure properly during exposure). The higher the temperature, the faster the diazo sensitizer decays and the greater the likelihood of exposure problems later."

For more info. go to How to Dry a Screen http://www.screenweb.com/prepress/cont/dryscreenb.htm

Good Luck!!!!!!

Edwin Rivera

posted on: Sat, 02/15/2003 - 5:14pm
Anonymous says: I would'nt take the chance of long time storage in that temp, the humidity will also get you. With the temp that high, coat your screen as you need them, I would guess, they would dry in about 30 minutes, ...

I would'nt take the chance of long time storage in that temp, the humidity will also get you. With the temp that high, coat your screen as you need them, I would guess, they would dry in about 30 minutes, this would give you time to mix your ink and have a cup of coffee.
Option #2, a small one room window air conditioner would probably keep it to around 75 degree which would'nt hurt to leave them for longer periods.

posted on: Tue, 03/04/2003 - 7:16am
Anonymous says: In very poor screen room conditions, I've had success using Saatitech's Grafic PU, with storage of up to 4 weeks in a screen room that didn't deserve to be called one. posted on: Wed, 03/05/2003 - 12:08pm
Anonymous says: So Edwin, I think what your saying is that the recomended temp to cure "unexposed" coated screens is somewhere around 110 degrees. That sounds good. We also know that "geting all the moisture out" is ...

So Edwin, I think what your saying is that the recomended temp to cure "unexposed" coated screens is somewhere around 110 degrees. That sounds good. We also know that "geting all the moisture out" is important. De-humidifiers in a small space (it doesn't have to be a "drying rack" specifically made for the job) along with an attemp at temperature control is important.

Any amount of trapped moisture in a screen about to be shot is tantamount to shooting yourself in the foot.

As for the storage of emulsions, the statement to the effect that the "activator" starts to loose integrity at anything above freezing means an old refrigerator with a working freezer in your screen room (or close thereabouts).

If your a smaller shop and would like to break up your gallon of emulsion you can, after sensitizing your emulsion (mixing well, and letting it sit until all the bubbles are gone), split up the gallon and store the unused portion in the freezer (in a tightly sealed container, leaving NO chance of moisture contamination) until needed (a test should be run the first few to test for storage times related to effectiveness)

If I'm sounding a bit "meticulous" about knowing what's going on with my emulsion, it's becuase I happen to think that, large and small, shops screw up their screen making because of ignorance of the process and lack of quality control more than any other department.

AnyWay, good advise all around guy's
Good Luck Steve

posted on: Mon, 03/10/2003 - 11:41pm
Anonymous says: Hello Steve, I am a screen room technician working for a mid sized plastic container printing company. We use Ulano direct emulsion applied using an automatic screen coater and we dry and store all of ...

Hello Steve,
I am a screen room technician working for a mid sized plastic container printing company. We use Ulano direct emulsion applied using an automatic screen coater and we dry and store all of our screens in a humidity controlled drying cabinet that has the temperature set at 100 degrees. We have stored screens for up to two months without encountering any problems. We have also used indirect emulsion (capillary film) with the same results. Hope this is helpful.
Beverly

posted on: Fri, 05/02/2003 - 4:12pm
Anonymous says: Sounds like Beverly and I work at the same place, I am also a screen room tech for over 15 years and we do basically the same process except we use Kiwo emulsion instead of Ulano, and we also have the ...

Sounds like Beverly and I work at the same place, I am also a screen room tech for over 15 years and we do basically the same process except we use Kiwo emulsion instead of Ulano, and we also have the same results with cap film. Gary

posted on: Mon, 03/22/2004 - 11:42am
Anonymous says: Did you go to school in Alameda California? posted on: Tue, 06/22/2004 - 8:52pm

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