Here you can discuss any issues related to working with water based screen printing inks. This would include curing, heat setting, mixing colors, additives, brands, usages and much more.
I attempted a couple of prints and had to abort mission. I used my old raggedy test shirt in the beginning and the mesh wasn't clearing on the part of the stencil closest to the clamp without some extra muscle. I got it to work, though a little smudged and figured I had a couple of extra shirts available for the run so I'd try on one or two of those. Things got a little better but I noticed after the first couple, my print started getting smudgey in that one area and I was getting inconsistent coverage. I was afraid the stencil was breaking down, so I stopped and washed out, completely unhappy with the few prints I got in, and now I'm trying to figure out what I need to change up.
The stencil looks fine on both sides of the screen. I just wonder if the fact that it's not centered (since I don't have a 20x20 platen) is causing me to have to overcompensate on the stroke and I'm getting too inconsistent & messy with it. I saw ink on the underside of the screen which made me afraid the stencil was degrading, but everything cleaned up ok. You can see the stencil here:
The part on the top-right is what's giving me fits.
You can see how atrocious the prints came out that smudged, too:
Should I re-do the stencil on a 16x20 screen, or is there something else I'm missing?
I may not be understanding everything going on here but I'll get you my 2 cents. What I do is use a t-square to mark my screen frame to identify their center point. I also mark the center of my print head. I also draw a line down the center of my platen using the t-square also. I line it all up. If you have center registration marks on your screen use them also.
As far as off contact, just use an off contact tab on the end of your screen where it rests on the platen. Using cardboard around the edges can lead to uneven off contact. Many times too much off contact can lead to your ink smearing. You can create a consistent off contact by using a flat, rigid, even piece of cardboard, metal, glass, etc. and laying on your platen and then screen resting on that as you tighten everything down. Just be sure that material is at least as big as your screen.
Platen size shouldn't matter as long as you image fits within it's area and the screen can snap off as your stroke clears the image.
Greg
If you're not going to go all the way then why bother going at all.
ApeShirt Apparel Printing, LLC
Very good advice ApeShirt. I agree with everything you stated and it is so difficult to diagnose things from afar but we do our best here.
I would defiantly agree the pallet shouldn’t matter if the design fits onto it and the screen is parallel to the pallet. That is critical so that the off contact is even in every spot between the pallet and the screen.
Also less off contact is always better than more. If the off contact is too high and parallel to the pallet it can cause problems on the print stroke that may flood or leave far too much ink on the print. If the off contact is too high and uneven it can cause serious issues in the print result due to a poor print stroke.
The screen and stencil look fine to me. It has to be how the screen is set up in the press in relation to the pallet. If you are using water based inks as suggested here and it's pretty thin then you may want a higher mesh count like 160 or 200. If the ink is thicker then a 125 or 110 should be fine. Also try a 70 durometer squeegee.
I hope that helps some. Thanks to ApeShirt for all his help on the forum!
Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!
I see you are using the 21 step scale (thank you)!!
looking at the photo it appears the stencil is way underexposed. You are looking for 7 solid steps and 8-21 wash away. The photo shows what looks like a solid step 4 ( I can only zoom in so much on this computer). I dont think this is your printing issue but You may have issues reclaiming this screen.
I *am* using the Saati scale actually, and it did wash out a bit low (around 4) but given that the rest of the detail on the stencil washed out well I decided to roll with it. I'm about to setup for attempt #2, and will try to adjust the off-contact down a bit. I had actually done everything you guys mentioned beforehand (using a piece of cardboard for an off-contact plate and then place tabs on afterward), except for placing a tab on the top and bottom of the screen. I think the piece of cardboard I used was rather thick, so I'll try to set it down a little lower and triple-check the tilt so that I don't feel like I have to mash the ink through the mesh on that upper end. I'll let you know how it goes!
Yeah, I feel like a tool. I haven't even really started adjusting yet, but I noticed the cardboard I was using is about 1/8". Found something that's 1/16" though and should work. Back to adjusting
Printing complete - yup, it was an off contact issue. For future reference, Those pre-paid priority boxes from the postal service are the perfect thickness for off-contact adjustment. Not that I'm advocating the destruction of government property or anything
Shamax wrote:Yeah, I feel like a tool. I haven't even really started adjusting yet, but I noticed the cardboard I was using is about 1/8". Found something that's 1/16" though and should work. Back to adjusting
It's much better to feel like a tool here than to your customer
Greg
If you're not going to go all the way then why bother going at all.
ApeShirt Apparel Printing, LLC
Nice! I’m happy we all could be of help. And I thought that was a Saati step calculator...LOL. That’s cool. I noticed it was washed out but the text in the stencil looked okay.
Off contact can be difficult to adjust, I’m glad you got it figured out.
Yeah I would agree with Apeshirt, it is better to ask and investigate then to struggle alone. So it’s all good, don’t feel like a tool...
Makes for a great post! Thanks for posting.
Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!
Just curious, when you say you stopped and washed the screen out?, did you actually take it off and go to wash out booth?, 'cause if so I would like to mention (you may already know this, but just in case) Screen Opener. If one part of your screen gets ink out side of image or dries in image you can just spray and wipe problem spot while on press and continue. Maybe not the best for skin, but I sometimes spray it on a rag to clean ink off a finger tip, haha.
