Curing Screens Help!!

[Vanishingstar05]

We are currently trying to burn our images into our screens and its not turning out.

We are using Graphic HU emulsion. We put one coat on both sides and put it in the light box for 6 mins and the image is not washing out easy at all.

We did one yesterday that had 3 coats of emulsion on it and cured for the same 6 mins and it came out really easy.

I dont want to ruin a bunch of screens. Is there something I am doing wrong? or do i just need to play with the curing time more?

 

[mikey-Oh]

step wedge test

 

[Just Another Sign Guy]

are you using a homemade 'light box'? or a professional exposure unit? either way get an exposure calculator, document your results so that you can duplicate them every time by following the same formula.

 

[WDP]

You can always DTG it

 

[G-Artist]

Direct emulsions can be a bear at times and your post shows it.

Have you ever considered indirect? Such as Ulano and others provide?

We gave up scoop coating many, many years ago. They are messy. There is no real way to determine the true thickness (over the entire screen). An expensive scoop coater can get nicked which renders it useless. All that plus if you blow a screen and need to make another immediately (within the hour) you had better have several pre-coated screens waiting. Plus storage of mixed emulsion does have a shelf life even if it is refrigerated in an opaque container.

With indirect, I can screw up a stencil and have a new image on the same screen and ready to print usually within the hour.

Sorry, can't solve your immediate problem but it does sound like it is either a mixing error problem or there was some sort of contamination of the chemicals. Best guess - some sort of pre-exposure of the emulsion to light before, during or after the screen was coated but before the exposure process so that the normal exposure hardened it like a rock.