How Long Do I Expose My Screens For?

[Catspit Productions]

Unfortunately, I am unfamiliar with the characteristics of the emulsion you are using and what you are doing. But even if I were, I couldn’t really give you any exact advice. There are too many variables involved that may affect your process that I cannot anticipate from here. Your film positives, emulsion thickness and light source will also affect your screen making procedures. Check out this video for tips on washing out screens:

http://www.youtube.com/watch?v=tRIFnYUucr0

http://www.youtube.com/watch?v=KM9uxI2bkPQ

Film positive tips:

http://www.youtube.com/watch?v=N6es7fC_CKw

Check out these articles to learn more about emulsions:

http://www.catspitproductionsllc.com/st ... mance.html

http://www.catspitproductionsllc.com/emulsiontips.html

http://www.catspitproductionsllc.com/li ... sions.html

http://www.catspitproductionsllc.com/em ... gtips.html

http://howtoscreenprintshirts.com/2010/ ... ual-cures/

Good luck and feel free to ask questions anytime!

[feignhpool]

hi although you cant help in how long to expose for im using an exposure lamp and the problem i have is that my sheet of glass keeps exploding , i think my heat source may be a little to close all help is apreciated

[Catspit Productions]

Yes, the bulb is too hot and that is not good as it can harden or “cure” the emulsion which is no good either. If the glass is breaking because of the excessive heat then the bulb is just way too close. Depending on the bulbs UV output, moving it farther form the screen will increase the exposure time.

A 500W to 1000W work lamp should work if you take the glass out. You just have to find the correct balance between distance and exposure time as to not over heat the emulsion on the screen.

Try moving it farther away and testing some exposure times to see if the bulbs UV output will suffice.

[feignhpool]

hi johnothan im managing to get the image onto the screen but the emulsion isnt washing out im not sure if its over exposure ?

[Catspit Productions]

Yes, in a way. It sounds like maybe your film positives are not dense enough. If some UV light can get through the black areas of your film positive you get a semi curing situation which will either make it very difficult to force out with more water pressure leaving jagged edges or it will not washout at all but you can see the latent image.

You may want to try a better film positive. My film positives are way better than copier transparencies, vellum and many other home techniques to making film positives. But water proof film positives will be the nest with dye inks in your inkjet printer.

http://www.catspitproductionsllc.com/in ... tives.html

You may want to watch this video as well:

http://www.youtube.com/watch?v=TuLWAU8RoDc

OR is the emulsion getting too hot still?

[feignhpool]

hi again all sorted im putting it down to over exposure and low water pressure so i invested in a high powered washer and all is well , i look forward to more videos keep it up jonno

[Catspit Productions]

Sounds good but you shouldn’t need a pressure washer to wash out a stencil. Regular hose or house pressure on a garden hose should be sufficient. If you force it out when it is semi cured you risk blowing out the stencil or at the very least saw-toothing. That’s when the edges of the stencil get jagged due to the emulsion being pushed of the corners of the mesh. Or the emulsion has poor adhesion or bridging characteristics.

But if what you are doing is working for you then go for it and good luck!