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screen printing => Waterbase and Discharge => Topic started by: screenprintguy on April 18, 2012, 06:50:21 PM
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I just saw a vid of Alan doing a print, discharge under base, then plastisol on finish. Alan, and anyone else doing this method.
1-Are you activating your UB any different then when you are just printing discharge normally?
2-Is there anything special needing to be added to the plastisol to make it adhere to the shirt over the water based discharge?
3-How is a simulated process plastisol print over a discharge under base coming out?
4-Can you use white discharge as your base?
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I just saw a vid of Alan doing a print, discharge under base, then plastisol on finish. Alan, and anyone else doing this method.
1-Are you activating your UB any different then when you are just printing discharge normally?
2-Is there anything special needing to be added to the plastisol to make it adhere to the shirt over the water based discharge?
3-How is a simulated process plastisol print over a discharge under base coming out?
4-Can you use white discharge as your base?
We do it all the time. We use matsui discharge white and discharge base .Make sure you flash your discharge white base so it doesn't pick up. With Discharge base it's best to not flash it, as there are spots that will show up.
When you put your garment through the dryer, test your cure time, as if it's to fast the discharge won't cure correctly, if it's to slow your plastisol may stick or bubble.
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Thanks man, I'm going to give it a try!
Mike
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Base to white ratio typically 70/30 or 80/20. Straight white is pretty chalky
tp
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I just saw a vid of Alan doing a print, discharge under base, then plastisol on finish. Alan, and anyone else doing this method.
1-Are you activating your UB any different then when you are just printing discharge normally?
2-Is there anything special needing to be added to the plastisol to make it adhere to the shirt over the water based discharge?
3-How is a simulated process plastisol print over a discharge under base coming out?
4-Can you use white discharge as your base?
I tried printing plastisol directly on a white discharge and it did not work. I think you have to base down the white discharge around 80% regular discharge base, 20% white discharge and then you can print on top of it with a plastisol but I haven't tried it yet.
We did a sim process on discharge base the other day and the print turned out much better than it did with a white plastisol base but we ran into issues with the discharge ink seeping to the shirt side of the screen at the edges of the tape and having misprints, but I never found out why it was happening. We've printed discharge enough and have never had this issue.
We do nothing different on either the discharge base or plastisol as we do if printing them alone, it's the exact same as plastisol underbasing but you don't really need to flash. I do flash just for a second or so for some reason I really don't know why, just do.
If I can figure out why I had seepage on the discharge screen I'll continue to use it more and more, but that job was 2500 pieces and we had to stop every 20 minutes or so to wipe down the screen and check for leakage and out of all those shirts, we had 20 misprints that had the discharge lines around where the edges of the tape was.
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Alan try hardenerX fromCCI. Designed to use in conjunction with there emulsion but it could work with what you use. It is a sodium hydroxide solution. I call it insurance
tp
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Base to white ratio typically 70/30 or 80/20. Straight white is pretty chalky
tp
This is a good recommendation for a successful BRIGHT white base under plastisol. And I agree Tony, straight white discharge is chalky and I don't see how plastisol could play well over top of that.
I have done a few jobs of just matsui bright base with cmyk over top and they turned out great. A highlight white thinned plastisol at the end would be icing on the cake and add no more feel to the garment than the process inks.
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I'll be doing a sim process design with a discharge base. I think my mix of 50% base and 50% white needs to be closer to your 70/30. . .and come to think of it, Rick did tell me that. . .I'll base down my HW too. I hope I can pull this off, I can always flash the base if I have to but I want to try this guy wow. . I'll put the screens in the sun for a bit to see if that helps with the hardening. . do you guys think 1/1 coating on emulsion is sufficient for a discharge base white? I think I'm dragging two threads in here, I'll start a new.
side note -Atlas was out of Sericol base but the fellow told me I can use the matsui bright base with the same results. . true? I have some here, maybe worth a shot on a small run.
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2 over two definitely......insurance against leaks!
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2 over 2 and post expose in the sun but make sure you dont underexpose initially.
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I was hoping not to have to use another additive and I've done 500-800 piece runs before and not had the issues I was having the other day. The screen wasn't breaking down in the sense that I think that it would, it was like the ink was seeping out of the tape on the inside of the screen but i never found any evidence at all that the ink got throu the barrier layer of tape. I'll take some pics of what the misprints looked like and the screen if I ever have time. We have printed more shirts in the last two weeks than any two week period we've been open, almost 20k imprints in the last 8 days. Not bad for a small crew. We normally do lots of small runs, but lately we've had 6 jobs over 1k pieces, one 2500 front/back and several more 600-800 piece ones. It's been a little ridiculous but it's a good thing.
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I usually tape inside and out and tape almost the whole back of the screen well at least as far as the squeegee/flood travel
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Hey Alan, just sent you an email with a ton of trial/error info.
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We experimented with this a number of years ago, and found a discharge base, not white, for the underbase, then the top colors including a highlight white
on 230, was working best for us. We haven't done it in a long time though, we're not that crazy about the smell...
Steve
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Hey Alan, just sent you an email with a ton of trial/error info.
Got it Mike, thanks. One thing different with this last run is the emulsion. I was using the 925WR as a matter of fact on past runs and had changed to the CP Tex recently and this was the first run of significant numbers with it so it's probably just not as good of an emulsion as the 925. I always post-expose so I guess I better bite the bullet and get some hardener in here for the longer runs and also switch back to the 925. I had zero issues on 500+ shirts with no hardener with the 925 so I'm going back to it.
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Hey Alan, just sent you an email with a ton of trial/error info.
Got it Mike, thanks. One thing different with this last run is the emulsion. I was using the 925WR as a matter of fact on past runs and had changed to the CP Tex recently and this was the first run of significant numbers with it so it's probably just not as good of an emulsion as the 925. I always post-expose so I guess I better bite the bullet and get some hardener in here for the longer runs and also switch back to the 925. I had zero issues on 500+ shirts with no hardener with the 925 so I'm going back to it.
We use cptex now and have zero problems with it. For longer runs we do use the CCI semi-hardner, and make sure that we tape up our screens really well, using split tape on the squeegee side, and clear tape on the substrate side.
It really depends on the job, but we've had pretty good success using a matsui clear discharge base or matsui white discharge base, through a 110 newman frame.
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Hey Alan, just sent you an email with a ton of trial/error info.
Got it Mike, thanks. One thing different with this last run is the emulsion. I was using the 925WR as a matter of fact on past runs and had changed to the CP Tex recently and this was the first run of significant numbers with it so it's probably just not as good of an emulsion as the 925. I always post-expose so I guess I better bite the bullet and get some hardener in here for the longer runs and also switch back to the 925. I had zero issues on 500+ shirts with no hardener with the 925 so I'm going back to it.
925WR just won't die, I bet I've used over 20 years. When something works, it works
Steve
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It's possible that I did something wrong on the CP Tex but I went through 3 screens for that job and you should have seen the tape job I did on that SOB, it was epic. I've still got the last one sitting off to the side so I can examine it so maybe I'll take a pic of that when I can. I post exposed for a good 10 minutes under the 10K lamp on all 3 screens and it just wasn't enough. I've got almost an entire gallon of the Tex so I want to go through it but if I still think I'll go back to the 925 when I'm done with it.
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For the base you guys are using 80/20 base/white? I just dont understand how that would be brighter than 100% white. Im gonna print a small run this afternoon and am gonna try it.
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Its not brighter, it's softer and easier to overprint. You do not need to discharge the garment to titanium white for an underbase.
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For a main white is 100% white the way to go then?
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Yes I usually thin with a bit of water though.
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I keep saying I want to try a discharge... I have a job (maybe) coming up that sounds just like this. It will be a rainbow (4cp) type print on about 500 each of 4 different shirt colors. I was thinking of a discharge underbase and plastisol on top. I will take any advise I can get.
Do any of the suppliers offer a sample or starter kit. I really want everything I need in one box.
Matt
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I keep saying I want to try a discharge... I have a job (maybe) coming up that sounds just like this. It will be a rainbow (4cp) type print on about 500 each of 4 different shirt colors. I was thinking of a discharge underbase and plastisol on top. I will take any advise I can get.
Do any of the suppliers offer a sample or starter kit. I really want everything I need in one box.
Matt
All you need is the emulsion that we've mentioned, the 925 preferably and a good manufacturers "Discharge Base w/ Activator". You don't need any pigment, or pigmented discharge ink or anything like that, just the straight base. I like the Jantex Discharge Base FS Sweet, it has served me well but I can't say I've tried any other regular base so others might be better at giving the advice on a better base. Well, you gotta have a scale too to measure out the correct activator % but those can be found cheap if you don't already have one. Mix the activator into enough base to get you through the print run and not any more. Once you add the activator you have to use what you've mixed within 8 hours (I've printed with it 24 hours after mixing without any issue) per the manufacturer's advice.
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I have been using CCI wr25 with great results buy my biggest run so far with this emulsion is 150 pieces so I can't say how well it will do for long runs.
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Just tossing this out there - I believe over-taping the underside actually accelerates the breakdown of a wb screen.
I tape minimally on the print side though I do stick a little border around the edge of the emulsion on the backside. WB ink really likes to wriggle it's way under all your tape it seems.
I've only done wb using some matsui rc colors on hankys and thin garments and then our TW flatstock inks on paper. The matsui doesn't even put a dent in a regular Aquasol HV screen (no diazo added), properly exposed, dried and post exposed. I doubt it could break it down at any length of run. The TW is more aggressive or, maybe not, since it is used with much thinner stencils and does indeed make an attempt an melting my stencils. I've found that letting the print side 'breath' helps a lot here. The underside tends to get slightly damp but if left free of tape will hold for the run. I'm guessing the water evaporates off out the back end or something like that. In the end, any screen getting damp on the print side has a stencil deficiency and I clearly need to add diazo to those stencils or find an alternate emulsion for those inks but it illustrates my point a little.
Anyways, this may be completely incorrect or it may be something that's technically true but too difficult to obtain in real life possibly, but it's what I'm seeing in my limited experience. I feel like you ought to be able to build wb screens that can hold through thousands of prints without over taping the underside or even taping at all.
Alan you have a 8kw halide unit right? That little solar entity ought to make wb screens to beat all hell if you expose at full wattage. Given proper exposure and post exposure, I'd ditch any emulsion that doesn't hold up after being blasted by that thing.
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I've done a few jobs that came out great with discharge base then plastisols on top.
I used regular packing tape since other tape the water based ink would slip around on. Worked fine for 600+ pieces.
One thing I had an issue with was that tack on the platens wasn't working due to the dampness. I was flashing for a couple seconds after the discharge base but tack wasn't quite working, any idea what to do?
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use the roll on tack they sell for the sprayers. works great. the water actually helps it stay tackier..
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use the roll on tack they sell for the sprayers. works great. the water actually helps it stay tackier..
right now I'm using mostly the Tekmar TP-HV carded on
spray tack for smaller jobs / inbetween to save time
but I'll see if just using the Tekbond TB-HV works better next time