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I'm needing a few small cap screens done with car logos on them. I may try to do them myself. What is the best emulsion to use? I will be screening with automotive urethane and cleaning up with lacquer thinner. Some of my striping buddies have been having problems with the emulsions washing out when using lacquer thinner.
-------------------- George Perkins Millington,TN. goatwell@bigriver.net
"I started out with nothing and still have most of it left"
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Ooooh...I would not recommend screen printing with auto urethane, unless you want to wash the screen out to open the threads up in between every print.
I've tried it with catalysed, reduced urethans, and it dries so fast I could not get a 2nd print of any quality, after the first print-despite a flood coat.
I tried using basecoat, and spraying a clear coat over afterwards. I was able to get 2 prints, before it was too dry to make a 3rd print.
As for emulsions, I used a diaz. uv-cure one (it's like pink PVA glue, photosensitive.) It held up very well.
I'd not recommend screening with urethanes at all, sorry George.
-------------------- "Stewey" on chat
"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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Stewart, they do it all the time over here. Single stage urethanes like the lower end Omni and PPG Concept. I use HOK and Hot Hues. I've got an old Cadillac screen somebody gave me and it's been used to death and works fine. A friend has been having his made at local shops but they haven't been holding up well. There are a couple of places that make the screens with the auto logos on them and they're not too bad price wise but they only come one logo to a screen. I'm looking to "gang" six or so different logos on a screen to save some space and a few bucks. I only do repair work at body shops, I don't do production work. It's almost always one logo per job
-------------------- George Perkins Millington,TN. goatwell@bigriver.net
"I started out with nothing and still have most of it left"
Any dual-cure emulsion should work fine. If lacquer thinner attacking the emulsion, my suspicion is that the screens haven't been burned properly.
I use Ulano Proclaim and have never had a problem cleaning the screens with lacquer thinner. I use it for everything - enamels, urethanes, UV and plastisol. The only thing that will cause it to fail is waterbased inks.
The issue is that emulsion (any emulsion) requires a specific amount of a specific wavelength of light in order to crosslink properly.
How long you'd need to leave it in the sunlight is like asking how long it takes to fill a bucket with water. Its going to depend how much water is pouring through faucet. Is the water dripping or is it pouring out full force.
Using the sun is the same way. Are you exposing at 9am, 12noon or 4pm? Is it a cloudless day or partly cloudy. All of these thing effect how much of that specific wavelength of light that the emulsion needs reaches the screen.
My recommendation is to burn the screen with a exposure unit. The key thing about any screen printing is that you need to have repeatable consistency. This is especially true when it comes to having trouble-free screens.
[ December 30, 2012, 12:26 PM: Message edited by: Glenn Taylor ]
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We have a proper exposure unit now, but used to use the sun. It took a while to calibrate both the sun & the unit properly, depending on the distance to the source, and the nature or opacity of the clear part of the screen-positive. (& the time of day & season- but I found 10:30 am - 1:00 pm relatively stable & reliable if it wasn't cloudy.)
The carbon-arc burner is reliable and FAST. You have to hold your breath though-don;t inhale the fumes.
Also, if the screen wasn't holding up, perhaps it hadn't been cleaned properly, before having the emulsion applied?
Good luck anyhow!
-------------------- "Stewey" on chat
"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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I use Autotype 2000.Nazdar has it and you can wash a screen many times over with laquer thinner and your image will remain clear and crisp.I expose my screens for 8 min on a florescent based vacum system.This works for me.
-------------------- Bill Wood Bill Wood, Sign Artist 3628 Ogburn Ave., NE Winston-Salem, NC 27105-3752 336-682-5820 Posts: 397 | From: Winston-Salem, NC | Registered: May 2006
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Can you expose this in sunlight?
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