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screen printing => Screen Making => Topic started by: noortrd on January 27, 2014, 08:45:41 AM
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Anybody tell us the good no diazo without hardener emulsion for water based?.
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honestly, it does not exist.
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I will second that....
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For long runs, I'll third that(can you third something?)
For basic and smaller runs we use Murakami HVP, allow for proper drying and post expose.
Longer runs we use Murakami SP1400. Holds up better on WB and is ridiculously cheap. Downside is longer exposure, need to mix in diazo, lower solids and more intensive reclaiming...
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For extremely long runs with home-made emulsion, some people don't use hardener. They use wood varnish. We don't do it in house, it is just too time consuming. We contract it out.
These are the steps.
1. expose screen as usual.
2. brush on wood varnish on one side of screen.
3. Lay the screen horizontal with varnish side up.
4. Use a rag dipped in methylated spirit and gently rub it on the other side of the screen. The methylated spirit will dilute the varnish and the cloth soaks up the diluted varnish.
5. Once dried, turn over and repeat the process.
The varnish acts as a water proof barrier.
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We have only done short runs but the Saati PHU hold up fine with a post exposure, usually in the sun.
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Ulano 925WR. Not the best in detail but it has excellent water resistance when properly exposed. It has a very wide exposure latitude though, so don't be fooled - it needs to be exposed out to the maximum end of the exposure range (before pinching detail) to get the best water resistance.
Hold up to discharge without hardening on small runs.
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The OP is looking for an emulsion that does not require diazo.
He wants the fast exposure of a photopolymer, but the water resistance of diazo or hardener without adding either.
Really tough search for this one.
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The OP is looking for an emulsion that does not require diazo.
He wants the fast exposure of a photopolymer, but the water resistance of diazo or hardener without adding either.
Really tough search for this one.
Doh. Didn't notice the "no diazo" part.
This is a have-cake-and-eat-it-too situation. If you want good water resistance, it's diazo or hardender or both.
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I thought the Xenon Nova and CCI HXT were options along with the Aquasol HV/P? Depends on your definition of long runs I guess but haven't there been printers here that have done 3-5K pieces with these emulsions above without using the optional diazo? We've done 1500 on one set of screens without diazo and we didn't do more because that was the size of the job.
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I thought the Xenon Nova and CCI HXT were options along with the Aquasol HV/P? Depends on your definition of long runs I guess but haven't there been printers here that have done 3-5K pieces with these emulsions above without using the optional diazo? We've done 1500 on one set of screens without diazo and we didn't do more because that was the size of the job.
I would bet that especially with discharge, most printers running 3-5k would use the hardener if they didn't want to lose the exposure speed by adding diazo.
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How long is the hardener step for everyone? Is it something that adds very little time to our pre-press discharge procedure. Spray on, wipe down both sides, sits in front of a fan for a minute or two and we're press ready. Others may spend more time on this step and the fact that we aren't doing thousands of pieces may be the reason this step being hurried hasn't bit us in the A-nus. Thoughts?
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How long is the hardener step for everyone? Is it something that adds very little time to our pre-press discharge procedure. Spray on, wipe down both sides, sits in front of a fan for a minute or two and we're press ready. Others may spend more time on this step and the fact that we aren't doing thousands of pieces may be the reason this step being hurried hasn't bit us in the A-nus. Thoughts?
The OP, noortrd will have to explain why he doesn't want to use hardener. Perhaps worry of reclaim difficulty?
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With Murakami's non-permanent hardener the extra effort in reclaim is minimal. The emulsion comes
off a little chunkier but other than that not much difference. Application is as easy as Alan described as well,
and given the small extra effort we use it on most runs over 50 or where fine detail/halftones are involved.
Cheap insurance.
We do let the hardener sit without a fan/sun for as long as possible though.
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With hardener application like any proper screen exposure it should be done at least a day in advance. I am almost positive that even the instructions on the hardener say to let set 24 in advance. I'm probably wrong though haha. I just like to have everything ready in advance. With the Aquasol emulsion before I sold my last shop we were doing large runs of several thousand no breakdown easy.
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With any hardener, higher heat (80 degrees to high 90's), lot's of air movement/low humidity, and at least 12 hours of dry time is recommended.
All emulsion companies will tell you to use the softest squeegee possible coupled with the lightest pressure possible to ensure maximum screen life.
I have not been able to exceed a couple thousand print strokes before screen breakdown using Murakami HV and Saati PHU with a general hardener. This is printing Discharge Inks.
If I make my screens bullet proof, I can exceed 10K impressions. At that point I just pop in new screens just to make sure nothing fails past 10k prints.
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Our first wave of testing to try and get a no post-expo, no hardener, durable emulsion made us conclude that we can eliminate post-expo but not hardening. There's lots more to test though.
Nova with Diazo is some amazing emulsion. Expo is very long and we do still need to apply hardener. I know others are getting the goods from Nova without hardening though. Nova can hold detail that is over the top and, unlike any emulsion we've yet to trial, will print a run with WB ink that is much more aggressive than many of the textile inks and, after cleanup in the booth, looks like it could run again. Our challenge with Nova has been getting the stencil's EOM where we need it, trying to get more EOM on the squeegee side in this case as delamination has been pretty much it's only weakness.
We were sent a pint, seriously a single pint, of CCI's HXT so we haven't been able to give it a fair shake. We dialed in the expo but the couple screens we put on press were pulled by my printer as they exhibited immediate issues....and then the pint was spent.
We have to revisit this in the Spring when it warms up, too cold to reliably ship emulsion right now and I think we may have had a "stale" bulb that we purchased so we need to retry things after we move.
Big time agree that cooking screens after hardening is beneficial. Alan at Murakami tipped us off to this awhile ago.
Has anyone tried Autosol 8000? TW Ink recommended it and their inks are the most aggressive WB inks I've ever seen or heard of.
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Just FYI - don't apply hardener and put the screen in the sun before it's fully dry, it can damage finer mesh. Found out the hard way.
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I should elaborate. We did post exposure on the Aquasol as well. I have been told even with proper exposure and when youthink you have it dialed in you still have aaround 10% percent that is not completely exposed. And as I was saying we did our reclaimable hardener a day in advance and let it sit in our "hot room" if that makes sense.
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Sorry for the misspellings on my phone and it's late. Good night everyone