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Screen printed tees

I've been making heavy use of long-sleeve tee shirts on this project, and I'm running low. So I thought, if I'm going to buy more, why buy a shirt with a goofy fake brand plastered all over the front, when I could plaster our own brand!?

But printing a one-off tee at customink run $40. Think of the money I could save if I spent a hundred bucks on screen printing equipment to do it myself! And now that we're buying tees, let's amortize all this trouble and print tees for all the family and maybe all the friends who visit...

(At this point, it would have been cheaper to hire a screen printing company to print a couple dozen shirts, but that would be missing the point. When Howells DIY something, apparently we also DIY the parts of that thing. Reminiscent of buying an embroidery machine to manufacture patches for space suits for the rocket...)

My first try was to make a mask on the vinyl cutter at work. It didn't stick very well to the nylon screen, but it did make a few successful prints:


Not being very sticky, the ink ended up squirting under the vinyl. It survived one effort at washing it off, but on the second try, the vinyl came off the screen.

Okay, let's do this the official way. I bought real photo-sensitive emulsion, mixed up a batch, spread it on the screen in my dark basement, then tucked it under a box in the dark storage room to dry off overnight. This morning I woke up and realized that the storage room was only dark because it was, you know, night last night. Well, there's still the box. I exposed the image onto the screen with 210W of photo lamps for 12 minutes, and went to wash off the unexposed emulsion:


I sprayed and sprayed, but by the time I got a hole in the screen, it started peeling too much off. Okay, so that didn't work. I suspect three things went wrong:

  1. the inadvertent exposure made the open parts of the screen stick too well,
  2. the 12 minute exposure wasn't quite enough, so the solid parts came loose, and/or
  3. the emulsion was way too thick, so the parts of the exposed emulsion adjacent to the screen didn't set well enough.
So I cleaned the screen, dried it off with a fan, then spread new emulsion, being careful to keep the layer as thin as I could. I used tarps to make my bike room into a darkroom, and dried that layer for a couple hours. Then I exposed it with the photo lights for 30 minutes.

This time, I could see the contrast between the dark blue-green exposed areas and the light green unexposed image. I sprayed it for quite a few minutes before the first hole appeared, but with persistence, eventually the image separated off successfully:



I put the screen up in the window to dry off and to be sure the mask was completely exposed and not likely to come unstuck during printing.

I haven't printed with this one yet, but I think it's likely to survive for plenty of prints.

However, I wasn't very excited to be back in a 1990s darkroom, fiddling with finicky photochemicals. I'd love to find a direct process to create the screen resist. I'm thinking of trying to lay down PLA with my 3D printer, or maybe using a laser cutter to make the screen from a sheet of mylar.

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