Here you can discuss issues related to exposing screens for screen printing. This includes determining the exposure, light sources and washing out the stencil in the washout booth. Emulsion issues may also be addressed here.
back of shirt held up to all the shirts, but I noticed that amount of paint used played a huge roll in crispness, so maybe that is where I went wrong on fronts.
This was the first shirt I did. They seem crisp to me, not perfect, but good
This was several shirts later and they continued like this
Neither...I have a blow dryer.I used waterbased speedball and Plaid paints. (yes the plaid paints are awful but I needed a cheap way to get those bright colors quickly, mixing to color was using too much paint) I hate that the crisp edges did not stay crisp. I'm not sure if this squeegee technique, paint drying in the edges of the design (this paint was VERY difficult to get out of my screen). When I washed my screen after printing the edges did not look like they do in the print, so I think the paint might have dried creating an uneven edge... I wanted to do a black ring around the ribbons and some lettering, but the walk is only days away and if I mess up I risk having no shirts.
I haven't used water based ink yet but I've heard it dries in the screen very quickly. Once its on there, you have to back flood the mesh and can keep a spray bottle of water to help some. I like to take too many breaks to use water base. Lol.
What is back flooding?? I did try wetting a small q-tip so as not to get ink on the shirt side of the screen, but that didn't do a great deal. If I had the heat gun I might like the ink you are using much better! I honestly think I got lazy and just screwed up.
I think Jonathan has a video on water base ink that may be useful to watch. He is very experienced with screen printing. Flooding or back flooding is filling the screen mesh with ink while the screen is raised off the shirt, to keep the ink from drying in the mesh. It would definitely be worth watching a short YouTube video. Its hard to explain but its done for a few reasons.
"Back-flooding" - refers to the practice of lifting your screen and gently dragging ink across the "open" ares of your stencil. It's especially important with water-based inks. Since water-based inks begin to tack-up/dry fairly quick, if you don't back-flood, you risk having ink dry in the open areas of your screen. This could cause holes in your design and an uneven coating of ink on your next prints. By making sure there's plenty of ink sitting on top of the open areas of mesh, however, it will dry slower.
Here's what I do when working with water-based inks:
1) With the screen raised, carefully pull some ink towards you, over top of the open stencil. I try to keep my squeegee fairly perpendicular to the screen when doing this and use as little downward pressure as possible.
2) Lower the screen, and push-stroke to print. I print with my squeegee at about a 60-degree angle.
3) Lift the screen, and repeat step 1
So back-flooding is important to do, but your problem sounds like it may be something else. You said that when you washed-out your screen, the edges of your design are now jagged? If so, then it sounds like the emulsion started to deteriorate or give way. The cause of that could be due to a couple of possibilities (or some combination):
1) Your stencil could be under-exposed, meaning you should let it sit under the light a little more before washing-out. Then, once you have washed it out and patted it dry, post-expose it to harden/strengthen it.
2) Your ink & emulsion could be incompatible. If your emulsion isn't rated for use with water-based inks, it could begin to breakdown after a few prints.
3) Too much squeegee pressure on your print strokes. This combined with either of the other two will add stress to the stencil and cause it to break down quicker.
Very awesome help here! Thanks to everyone for helping out. There are some great tips here. Here’s my 2 cents worth.
Here is a video in which you will see me back flood the screen and talk about it.
Also with water based inks your print problem may be as simple as using a higher mesh count so not as much of the very thin water based inks print.
Water based inks which tend to be thinner than plastisol will print better with higher resolution on a higher mesh count like a 195, 200 or 230.
From the looks of your screen mesh you are using a 110 or maybe lower? That could be the problem with the way the ink is printing and with the jagged edges to your design.
Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!
Thanks and you are right I am using a low mesh count screen so printing fine lines has been a challenge. Thinking I need to invest in a 220 screen and maybe just a little longer exposure times.
Finished my second set of tee's for the Myasthenia Gravis Walk and I have to say Thank You to all of you for the tips! I let my emulsion dry a great deal longer to be sure that it was fully dried before burning it. I extended my burn time by about 30 seconds, so not too long, but a little more. I rinsed my image after burning in a still darkened room (before I had just flipped the light and got it to water quickly) and lastly I remembered to try flooding the screen between prints. I was worried flooding would cause too much paint blurring the design, but was relieved to see that didn't happen and that my lines stayed much sharper to the original image. Just wanted to say thank you and show you the difference.
I wanted to do a black ring around the ribbons and some lettering, but the walk is only days away and if I mess up I risk having no shirts.
