exposing time with 200 wt bulb

Here you can discuss issues related to exposing screens for screen printing. This includes determining the exposure, light sources and washing out the stencil in the washout booth. Emulsion issues may also be addressed here.

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saurabh
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exposing time with 200 wt bulb

Postby saurabh » Mon Nov 30, 2015 5:33 am

Hello,
i am using 200 wt bulb for my exposing unit.The distance between glass and bulb is approx 12 inches .what time would it take to burn a screen and does it depends on the type of stuff we are printing?
Like if printing alphabets(normal font) ,is it going to take less time than alphabets with bold font and other A4 size designs.please help, i am trying this since 5 days still not making any success :( .
i am using ez film instead of emulsion.
Also,does the exposing time depends on mesh size?

thanks


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Re: exposing time with 200 wt bulb

Postby Catspit Productions » Mon Nov 30, 2015 5:03 pm

Screen exposures vary depending on several variables the first and foremost being the emulsion. Then the light source and film positive also play a part in the proper exposure as well as climate conditions where you work. The first thing I will tell you is to get at least a 500 watt work lamp from Home Depot. That will work much better at exposing emulsion.

Also you may want to contact EZ Screenprint for technical assistance as they will have suggestions for exposure times with different light sources. I have never worked with that product so I am unfamiliar with how fast it will expose. Here is a video about screen exposure times and why I cannot necessarily tell you how long to burn:



But yes, exposure times will vary depending on the artwork and screen mesh count sometimes. Most of the time we can get an exposure time that works for our emulsion and light source and it will only vary slightly if at all. Here is a very general guide to choosing mesh counts:

Use a 28 to 30 mesh count for printing many brands glitter inks. Always check with the manufacturer of the ink about this. This mesh will print a very high volume of ink and have a thick coat of emulsion making it difficult to expose.
Use an 85 mesh count for athletic printing, opaque ink deposits, thick puff ink, and some shimmer inks. This mesh will print a very high volume of ink and have a thick coat of emulsion making it difficult to expose.
Use a 110 mesh count for heavy coverage on dark shirts, solid under base prints, puff, metallic, some shimmer inks, and for certain transfer printing. This is a great mesh count for high opacity inks on any dark garments.
Use a 155 or 160 mesh count for general printing on white tee shirts & under basing on dark shirts, prints on nylon jackets, and thinner silver shimmer inks. Many thinner plastisol inks will print well with this mesh count.
Use a 195 mesh count for printing on light colored T-shirts with fine detail, line work or halftones of around 35 LPI.
Use a 230 mesh count for printing on light colored tee shirts with fine detail, line work or halftones of around 45 LPI.
Use a 305 to 355 mesh count for process color on light shirts, or for overprinting a halftone on a white under base on dark shirts. You should be able to pull of halftones of up to 65 LPI but a 55 LPI is most common.

It takes some time to learning these things through experience.
Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!

http://catspitscreenprintsupply.com/
http://www.youtube.com/user/CatspitProductions

saurabh
Posts: 4
Joined: Mon Sep 28, 2015 9:45 am

Re: exposing time with 200 wt bulb

Postby saurabh » Mon Nov 30, 2015 10:37 pm

What should be the distance between glass and the bulb and is it okay to have exposing unit of wood?

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Re: exposing time with 200 wt bulb

Postby Catspit Productions » Tue Dec 01, 2015 10:57 am

Sure, you can use wood, PVC pipe or even hang it. Normally we are dealing with anywhere between 18 to 24 inches distance. That's what my basic exposure unit will adjust to.

http://catspitscreenprintsupply.com/cat ... ure-light/

That's a fancy adjustable metal stand with a 500 watt work lamp, no glass. But you can use anything to build the stand.
Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!

http://catspitscreenprintsupply.com/
http://www.youtube.com/user/CatspitProductions


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