HiBYRD

Hello! Today I had my first encounter with emulsion. In case it helps, I'm using the Diazo emulsion kit.

I read online that you can use sunlight (especially in the summer) to burn the emulsion, so i tried it out on this sunny, summer day. I took the frame outside, put a black cloth underneath, then glass on top of the transparency. I really had no idea how long to keep it outside, so after about 15/20 minutes I came back and noticed the emulsion was blue, and decided to try to wash it off.

However, it didn't wash off that well. You can tell it kind of washed off (if you hold it at a particular angle), but I'm pretty sure I can't make prints off of it.

So, what happened? Can I not use sunlight, or did I not give it enough time in the sun?

Or, is this because of my transparency? I printed it on my printer, but it seemed opaque enough for me. Should I get it photocopied on a laser printer or something?

**

Also, a totally unrelated question about another rumor I heard: Is the tension on the edges of the screen (about 1-2" away from the frame) too high to be able to print there? Does that make sense? I mean, my design almost touches the frames, it takes up so much space on the screen. Is it too close that the tension will be too high to allow me to print?


Whew. Thanks a lot for any help!

 

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majkthreads

Trust me I'm new at this but I believe for sun time your looking more in the range of 1-3 minutes would be closer. I'm sure someone with more experience will post and let you know.

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Candace With HCB

It takes about 30 seconds to cure emulsion in the sun. you are over exposing big time. make sure you have the transparency in place before any sunlight touches the screen. you can set it up on a black board and then bring it outside.

Burning 101
I don't know what you know already so I will explain like you know nothing about burning a screen. to be informative not insulting =)

Emulsion is a chemical that is sensitive to UV rays. when UV light meets Emulsion the chemical starts to cure(harden). the image on the transparency blocks the UV rays from hitting the screen where you want your image so it doesn't cure. then you can wash the uncured emulsion out of the screen. and the ink can go though at that part of the screen

the silk screen is acually polyester mesh material attached to a frame. the mesh count is the number of holes per square inch. the higher the count the finer the detail and less ink will pass through the screen. the lower counts allow more ink to go though but cannot be used for intricate art work or small lettering. they are used for sweatshirts or the white undercoat if printing on dark T's.

It is my goal to help people start succeeding in t shirt printing. If I have helped please let me know.

 

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HiBYRD

Thank you both for your help! I can't believe I was so daft.

So do you think my screen is ruined now?

 

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majkthreads

I would think you would be able to soak it for a few minutes in reclaimer and try to wash it out.

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RichardGreaves

You have to learn how to make an exposure test so you don't under or over expose your stencil.

Ulano has a video you can download and watch over and over:
Support Menu of Screen Making Products

It is the link at the top.

Notice they also have 2 general videos on capillary film and direct emulsion under the 'general' tab. Watch those movies to learn how to reclaim a stencil once you are done with it.
=============

Stencils are easy. If it washes out, it wasn't exposed to enough UV-A light.
Unexposed stencil should wash out easily.

If it is hard to wash out, it was exposed to heat or UV energy and has started to cross link.

Test to see if your positive is blocking UV light. It some UV light leaks through the the positive, it can prevent the stencil from washing out in the image area.

The next time you expose, attach a coin to the stencil which will not let any light pass.

You are using a diazo sensitizer which changes the stencil color as the UV energy activates it. SBQ stencils are MUCH faster but there is no color change, so I suggest you keep to the diazo.

I posted an answer to "sun exposure" in the past:
Exposure using the sun!??!

Search for "sun exposure" in this forum.
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Read my post on mesh resistance:
squeegee size

Mesh resistance is not equal on a screen printing frame. Combine that with a plastic blade that bends according to the resistance it experiences, and you have different ink deposits.

More 'free' mesh is better if you need a distortion free print.

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Solmu

Quote: Originally Posted by HiBYRD Is the tension on the edges of the screen (about 1-2" away from the frame) too high to be able to print there?

The other day I wasn't thinking, and I accidentally exposed an image with the edge being about 1" away from the top edge of the frame. It certainly makes it difficult to print, but it is possible. I certainly wouldn't make a habit of it though.

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