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screen printing => Screen Making => Topic started by: Prosperi-Tees on May 01, 2017, 06:49:23 PM
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Can you use diazo emulsion without adding the diazo? Why or why not?
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No. Without the Diazo, it has no reactivity with light. It's just essentially block-out.
Used to make our own at one shop with white glue, coloring, and I think sodium bichromate to make it photographically sensitive.
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I had a guy who threw away the diazo and coated screens with unsensitized emulsion. That was fun times troubleshooting
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Ok thanks. I was curious if the diazo was just for water resistance. I've been using sp1400 and while I love the price, the reclaiming is a bit tougher. Still have a couple gallons to go thru before thinking about changing to a one part with easier reclaim. Any suggestions on an inexpensive one part emulsion? Might be hard to beat the $30 sp1400 though.
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Can't beat the price of 30 bucks but a really good two part emulsion is Imagemate DC-521 44.95 a gal from Valleylitho.com which is now called Superior Screen Printing Supplies. Homer turned me on to HXT works with water base or DC inks I can't tell you the price I just order it might need to see what I'm paying LOL.
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I tried a 2 part from Xenon that reclaimed like a dream but was pinhole city so that one is out. I dont need water resistance. I am thinking of trying Ulano Orange again. It is about $45 a gal. I figure I could cut my exposure times in half and save a minute or so per screen and then I will be ahead of the game.
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I tried a 2 part from Xenon that reclaimed like a dream but was pinhole city so that one is out. I dont need water resistance. I am thinking of trying Ulano Orange again. It is about $45 a gal. I figure I could cut my exposure times in half and save a minute or so per screen and then I will be ahead of the game.
Pinholes are unlikely to be caused by a specific emulsion, but rather are a product of less-than-stellar housekeeping. Perhaps, though, some are more forgiving than others.
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Maybe so, but I experience zero pinholes on the SP1400, I can't remember having one for a couple years at least, once I switched over to the Xenon, pinholes. Can pinholes be caused by overexposure?
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For me. Pin holes are caused by good emulsion that can expose fine details. We need to wipe down our glass before exposure.
Spot colour: local emulsion, $5/kg
Halftone: imported $20/kg
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whats the differnce between diazo and presensitize emulsion? in presensitize they add diazo before?.
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Maybe so, but I experience zero pinholes on the SP1400, I can't remember having one for a couple years at least, once I switched over to the Xenon, pinholes. Can pinholes be caused by overexposure?
Pinholes are typically specks of dust which either break through during a run, or during developing. Overexposure would tend to make them bust through less due to stronger emulsion.
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whats the differnce between diazo and presensitize emulsion? in presensitize they add diazo before?.
Well, they add a sensitizer different than diazo. A photoreactive salt (Styryl Basolium Quaternary), is bonded to the polyvinyl base during the manufacturing process.
It has a much longer shelf life.
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I know we all want to save a buck or two but to me at least it seems that is one
of the things I don't mind paying for. Good SCREEN printing starts with good SCREENS.
I use the emulsion that works best for me regardless of the cost. I can cut corners in
other less critical areas.
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I agree. Thats why I want to shave some exposure time and some reclaim time. Just have to find one that works for me.
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SP-1400 reclaim issues? Diazo's are some of the easiest to reclaim. Try mixing ER-605 from Murakami at 8 parts water to 1 part ER-605. Are you letting the emulsion remover dry at all on the screen before blasting out? If so emulsion remover that is left to dry on a screen can make it almost permanent. the other tip would be to use a dip tank for reclaiming. PM me for other additives for hardened screens. Still reclaimable. Are you reclaiming with a pressure washer as well? Stronger PSI always helps in reclaiming. Used to have a 5000 psi pressure washer that could reclaim without emulsion remover!
Frog: Glad you are still kicking after using Bichromate sensitizer. For those that are unaware this is one serious cancer causing sensitizer that should never be used. There are a few parts of the world who still use it and it can kill all aquatic life in a stream for years for miles downstream.
Al
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Frog: Glad you are still kicking after using Bichromate sensitizer. For those that are unaware this is one serious cancer causing sensitizer that should never be used. There are a few parts of the world who still use it and it can kill all aquatic life in a stream for years for miles downstream.
Al
Next thing you're going to tell me that back in '63, we were supposed to know that we shouldn't clean polyester resin off of our skin with acetone.
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I was always under the impression that diazo emulsions were more difficult to reclaim due to their water resistance. I would not say I am having issues with reclaiming, I would say that it takes longer to reclaim than the Ulano Orange that I tried and also the Xenon diazo emulsion that I tried, those two emulsion just melted off the screen. The SP1400 takes a little more elbow grease with the pressure washer to get it done. I could use an upgrade at pressure washer as I use a cheap Lowes job.
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Yeah how did we survive those inks and then use MEK, Acetone, Butyl cellosolve or some exotic vinyl ink wash. I used to print the hang tags for our line of clothing with incredibly strong aromatic vinyl inks by hand on large screens. Late night hand printing away with the vinyl inks and the next thing I know I'm looking at the ceiling and the ink is totally dry in the screen. Or those Colonial tex-dyes that were pure Xylene. We are the Darwinian gene pool that survived those years!
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Prosper-tees PM me so I can get you a sample of Emulsion Remover that you can adjust to get the concentration that works to remove SP-1400.
Al
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Frog: Glad you are still kicking after using Bichromate sensitizer. For those that are unaware this is one serious cancer causing sensitizer that should never be used. There are a few parts of the world who still use it and it can kill all aquatic life in a stream for years for miles downstream.
Al
Next thing you're going to tell me that back in '63, we were supposed to know that we shouldn't clean polyester resin off of our skin with acetone.
That list of chems, along with the bichromate and lets not forget the carbon rod arc exposure! A toxic cocktail for sure. Surprising that you print pioneers did not end up like this poor guy.
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So the monsters we see in the movies are really old screen printers?