[Coreycss21]

Hey everyone,

So I?m still new to screen printing and was wondering if someone could give me guidance on exposing Photopolymer emsulsions. I?m using a 500w light for exposing and was wondering what a general time would be to expose and distance. I?m going to use a exposer calculator but was wondering just where to start at.

Thanks!

 

[wncprinter]

Hey everyone,

So I?m still new to screen printing and was wondering if someone could give me guidance on exposing Photopolymer emsulsions. I?m using a 500w light for exposing and was wondering what a general time would be to expose and distance. I?m going to use a exposer calculator but was wondering just where to start at.

Thanks!

I used the emulsion with the diazo additive forever before I tried the photopolymer. Originally the burn time was close to 15 minutes. If you do this part time and need to expose multiple screens in the evening...well, there goes your entire evening.

I switched to Ryonet's Hi FI photopolymer and I have never looked back. I feel like I am pushing the envelope of what your supposed to do, so you may need to experiment with your exposure time...as well as the distance between your light and the screen. Mine rides above the screen, instead of underneath.

I have mine set to about 5 minutes and 10 seconds. And when I spray the screen out, I use the "Mist" setting on the nozzle, especially when exposing screens with a lot of detail. I also use the side of the scoop coater with the thicker edge to lay down a slightly thicker stencil. The emulsion just gracefully falls out leaving a perfect clean stencil.

 

[kraire]

I've been using a 500w lamp for a while now, around 60cm distance, I've got 30 mins to work on something else until it's fully exposed. It's been OK for me until recently, but time is getting expensive as we're growing. You might want to set the lamp so it "fills" your screen, you don't want unnecessary spread of the light. I'd say start around 30-40cm, but screw around, take a few tries for setting the height.

Here's acmebandsupply's comment from another thread:

Exposure is completely unique to everyone?s own setup. Consider it trial and error until you come up with a combination that works. Someone here could list step by step how they come to a properly exposed screen, but it?s pretty worthless unless they?re using 100% of what you are, and the weather that person is experiencing is also the same. It doesn?t matter what exposure unit you bought, itl probably work. But you need to start testing. My guess would be on attempt 3-5 you?ll have something that comes out completely accurate. Get an exposure calculator to at least get you going in the right direction. And even that needs to be retested as seasons change, bulbs weaken, emulsion weakens it gets older, if you change coating procedures (1:1, 1:2, 2:2), how dark your films are... different exposure times for each different mesh and mesh colors..