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Screen coating and printing tips

Posted: Thu Aug 16, 2007 12:10 pm
by cordogg52
During my last job I ran into two problems I can't seem to conquer. First, when coating the screens with a 1:1 method and letting them dry squeege side up there are circular dots of raised emulsion that will appear in some places on the dried screen. I feel as if it is too think and dripping down but I really didn't think I coated it on that thick. Any tips on how to do a smooth and consistent coat??
Second, when printing the shirts some ink will go throught and onto the platten. I'm using a 70 durometer squeege with a push stroke. Flood strokes don't seem to work well for me. It's either a very light and somewhat uneven print or a decent looking print that will leave some ink on the platten. I'm have at least an 1/8" off contact with a athletic ink. Any advice on this?? Thanks in advance for anyone willing to share some insight into these problems i'm having.

Posted: Wed Nov 21, 2007 1:33 pm
by rickmiles
Hi cordogg52,

You may have your problem solved by now. I just found this forum and just registered, I'm an old re-tired (in 1982) Electronic Screen printer for about 40 years.

One time when I was a new Production supervisor for a Circuit Board company. One of the problems they were having was the emulsion was breaking down in random places, they were using stainless screen mesh but it could happen no matter what kind of mesh you use.

In prepping the screen they were scrubbing the mesh with a cleanser the kind with grit in it, you know the regular household cleanser. and when they rinsed the screen off and dried the screen it left tiny little grit spots that they did not notice and left a lot of tiny bumps all over the screen after the screen was coated with emulsion. And that was the part that was breaking down.

I threw out abourt 8 cases of cleanser, I took it right to the dumpster, they thought I was crazy (I probably was in them days) I went to the store and bought ..I think it's called polishing cleanser or the kind with no grit. Anyways to make a long story short there production went up about 1000% They had to no longer stop production 2 or 3 times to make new screens..and this is a true story.

As far as your other problem screening on cloth. I specialized in Electronic screen printing, fine printing on panels, dials, nameplates on metal or plastic , and I also did etched and MetalPhoto nameplates etc...and I screened on cloth as a favor to my customers for special projects. The way I did it ..on cloth I made full contact with the substrate in this case the cloth no off contact and I never screen away from me unless I'm flood coating ..I always pull the squeegee towards me.

I don't know how the Ink is getting on the platten I'd need more Information...On coating the screen ..you can always give the screen 23 or four this coats ..dry between coats ...Just make sure you make notes on the exposure for how many coats you use.

I hope this helped you or anyone else.

Rick
http://screenprintingsales.com/
http://allnaturalstoneandtile.com/
rick@screenprintingsales.com

Posted: Wed Nov 21, 2007 4:24 pm
by yaleteamsandtees
Describe your idea of what a flood stroke is.

I feel you have to master the flood and pull stroke before trying a push.
(But that's just my opinion)

-Rob

Posted: Wed Nov 21, 2007 7:48 pm
by rickmiles
Hi Rob,

I just noticed your in Gaithersburg, Md.


I had a Electronic screen printing business in Gaithersbug on Luane dr called Metal Impressions and I sold it in 1982 to Prestige Screen Printing in Rockville
I also had a Circuit board business in Wheaton called Circuit Labs and a Hot stamp roll label and Etched nameplate business in Rockville, Md

Small world.

Have a nice day,

Rick

Posted: Wed Nov 21, 2007 10:32 pm
by ROADSIDE
Heres a tip.... Keep your liquid emulsion in a fridge.

You prolly laying the emulsion on to thick and if its not cold its very drippy.

It works.

also I would try coating both sides twice and on the last one, scoop coat instead of apply coat.... take away extra emulsion.

Posted: Thu Nov 22, 2007 10:52 am
by rickmiles
Sorry,
I don't know how the Ink is getting on the platten I'd need more Information...On coating the screen ..you can always give the screen 23 or four this coats ..dry between coats ...Just make sure you make notes on the exposure for how many coats you use.
Should read:
2 to 3 or four thin coats

Rick

Posted: Fri Nov 23, 2007 10:37 am
by yaleteamsandtees
Rick, I've met you.

When you closed up shop we got a few things from you.

I used that old file cabinet until it just plain wore out!! 8)

Where are you hanging out these days?

-Rob

Posted: Fri Nov 23, 2007 5:05 pm
by rickmiles
Hi Rob,

I'm in Antioch, California now.

What company did I have at the time when you bought the cabinet and what year.

I'm trying to picture you, are you the one that bought about 50 t shirt screens from me in about 1987?

Rick

Posted: Wed Nov 28, 2007 1:30 pm
by yaleteamsandtees
You were in the Airpark on Cessna
down by M&M Welding.

Posted: Fri Dec 07, 2007 11:47 am
by rickmiles
Rob,

Yea that was about 4 years after I sold my business and signed a 5 year non compete contract....biggest mistake I made in my life. I tried to start a new screen printing business in the airpark, I was living at the Airpark ...(to save money) I was separated, and my old lady decided to run away and dropped off the kids ...you can't start a business while taking care of 3 little boys living in a warehouse ...that ended my business adventures...I moved here to California got a job and raised my kids.

Rick

Posted: Fri Dec 07, 2007 12:33 pm
by ROADSIDE
wow rick that was a tragic post.

sounds like a top 10 country western song.

glad to see you survived the ordeal

Re: Screen coating and printing tips

Posted: Wed Aug 05, 2009 6:06 am
by taglessthreads.com
Try using the sharp edge of a scoop coater. It also sounds like the emulsion isn't drying fast enough which allows drips to form. I suggest building yourself a box to keep light out and stick a small $20 fan from Home Depot on the side to speed the drying time. A large cardboard box would work if you don't feel like getting fancy and building a box.

Re: Screen coating tips

Posted: Wed Jul 14, 2010 5:35 am
by Business Forms
Hi..

Some Screen coating Tips

> Only coat your screens under red or yellow safelight conditions.

> Mix your emulsion well before dispensing it into your scoop coater.

> A scoop coater should be clean and its edges free of dents and nicks. A smooth edge is best.

> Make sure the scoop coater is well filled. You don’t want to run out of emulsion halfway up the screen.

> Once the scoop coater is filled, the emulsion should be applied immediately. Emulsion left sitting in the open is a target for dust and debris.

> In low humidity environments, an open container of emulsion can begin to form a skin quickly, so keep your emulsion in an air tight container until you need it and after you apply it wash out your scoop coater right away.

> Once the emulsion makes contact with the mesh, proceed slowly. Emulsion is viscous, and it needs time to fill the mesh openings. Use a slow smooth passing action to move the scoop coater up the screen. Moving too fast can trap air bubbles in the emulsion and when they pop, the mesh can remain open creating pinholes.

> Coat the substrate side of the screen first. Begin your coating pass at the bottom of the screen. Firmly support your screen as you press the edge of the scoop coater against the mesh. Move slowly up the screen and slow down to a stop near the top. Twist the scoop coater upwards and off of the mesh. Flip the screen quickly and repeat on the ink well side.


Thanks for......