First, I am, BY NO MEANS, a pro. (I just play one in my shop). If I'm wrong, someone will chime in. 
**2 coats of emulsion-- 1:1. Coat the shirt side first-- (the flat side), then coat the squeegee side. (The side you use the squeegee) This gives for better coverage, and a more even film of emulsion. Which is necessary for proper burning and getting a nice, crisp image.
**ALWAYS dry your screen horizontally so the emulsion can settle properly. When drying, always dry shirt side down. I understand the lack of space, but these things are essential to getting a good screen developed.
**Scoop coater. Ok....your screen is 20X28, coater is 10". I would rotate the screen to a landscape position and do 2 passes, side by side, with as little overlap in the middle as possible. (Just my .02 on that one) I think you're less likely to have runs, overlapping marks where it will take more development time, less buildup which would increase exposure time, too. (Figuring 2 passes will cover your 28" long screen--giving about 2" width on either end for frame, that means you now have approx 24" to cover. You can lose about an inch on each end of the mesh, won't need that space anyways--that leaves you with about 22" to cover in 2 passes---doable, IMHO)
**Was your emulsion completely dry when you started the exposure?? Are you sure....? I've made that mistake and ruined the image because the emulsion wasnt properly dried and cured and ready to be burnt. Again, JMHO. Keeping in mind that if it's very humid, it will take longer to dry, etc.
** Sounds like under exposure. With 1-500w halogen, at that distance, should've been longer. I use 2-1000W worklights, placed about 10-12" from the image, it takes about 3-3 1/2 mins.
** Pressure washing *shouldn't* wash out your emulsion, IF properly cured. I run water (no pressure) over the screen, both sides, let it sit for about 5 minutes, then start rinsing. Sometimes this is enough to wash the image out. Sometimes I DO actually use the pressure.
I saw your post about your drying situation, and LOVED andimill's response. Not difficult, not costly and once they are dry, THEN cover and stand them up.
YMMV.
Good luck!
**2 coats of emulsion-- 1:1. Coat the shirt side first-- (the flat side), then coat the squeegee side. (The side you use the squeegee) This gives for better coverage, and a more even film of emulsion. Which is necessary for proper burning and getting a nice, crisp image.
**ALWAYS dry your screen horizontally so the emulsion can settle properly. When drying, always dry shirt side down. I understand the lack of space, but these things are essential to getting a good screen developed.
**Scoop coater. Ok....your screen is 20X28, coater is 10". I would rotate the screen to a landscape position and do 2 passes, side by side, with as little overlap in the middle as possible. (Just my .02 on that one) I think you're less likely to have runs, overlapping marks where it will take more development time, less buildup which would increase exposure time, too. (Figuring 2 passes will cover your 28" long screen--giving about 2" width on either end for frame, that means you now have approx 24" to cover. You can lose about an inch on each end of the mesh, won't need that space anyways--that leaves you with about 22" to cover in 2 passes---doable, IMHO)
**Was your emulsion completely dry when you started the exposure?? Are you sure....? I've made that mistake and ruined the image because the emulsion wasnt properly dried and cured and ready to be burnt. Again, JMHO. Keeping in mind that if it's very humid, it will take longer to dry, etc.
** Sounds like under exposure. With 1-500w halogen, at that distance, should've been longer. I use 2-1000W worklights, placed about 10-12" from the image, it takes about 3-3 1/2 mins.
** Pressure washing *shouldn't* wash out your emulsion, IF properly cured. I run water (no pressure) over the screen, both sides, let it sit for about 5 minutes, then start rinsing. Sometimes this is enough to wash the image out. Sometimes I DO actually use the pressure.
I saw your post about your drying situation, and LOVED andimill's response. Not difficult, not costly and once they are dry, THEN cover and stand them up.
YMMV.
Good luck!
