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screen printing => Waterbase and Discharge => Topic started by: sqslabs on December 29, 2014, 11:14:41 AM
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So I recently received my new press (RPM Revolution), and it is the first press I've ever had with a chopper setup, so for the most part I've had to start from square one again, which also happened to coincide with my busiest month this year. I got my plastisol prints dialed in very quickly, but have really been struggling with discharge jobs on the new setup.
Since my first discharge job on the new press, I've struggled with ink rapidly drying in the screen, lack of penetration, squeegees stuttering down the screen, and many other fun and exciting issues. These aren't issues I ran into on the old press, so I'm a bit stumped as to exactly what's going on. Many of the problems have been related to white discharge, both Matsui (mixed 50% Discharge White, 50% Discharge Base, 6% Activator), and CCI (D-White straight out of the bucket with 5% activator). I've been running that Matsui mix for six years and never ran into these issues with it until recent months, but from what I've heard they haven't changed the formulas at all. I'm new to D-White, but haven't seen much difference with that either. I'll be testing a different batch of Matsui White today as well as implementing a new batch of activator to see if it changes anything. I've also ordered in some Matsui Brite Base to test as an option, and will be giving the Rutland white a shot as well.
My squeegees are at 12-15 degrees, 70 duro, and running at 40 PSI, double stroke. I am seeing some head/pallet deflection, but from what I've been told it isn't any more than normal on this press. I'm running everything through 150S mesh with minimal off contact.
I've already reprinted roughly 300-400 shirts this month, and am currently at my wits end. With the new press/chopper system in addition to the inks themselves there are now so many variables involved that I'm having trouble isolating the issue and am running out of time to get the jobs completed. Any input would be greatly appreciated as I'm on the verge of placing my head between two pallets and indexing the press.
Thank youuuu. 8)
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Will be watching this for later as we haven't run any discharge/wb jobs on our new press...
and if I remember correctly, you also converted from a javelin v-squeegee setup right?
on our chopper heads on our old Javelin, we used to run at 50-60psi, 70/90/70 duro, 20ish degree angle with very few problems...
will be interested to see what others recommend.
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Will be watching this for later as we haven't run any discharge/wb jobs on our new press...
and if I remember correctly, you also converted from a javelin v-squeegee setup right?
on our chopper heads on our old Javelin, we used to run at 50-60psi, 70/90/70 duro, 20ish degree angle with very few problems...
will be interested to see what others recommend.
Yep, our Javelin is 100% v-squeegees so the chopper setup is a whole new ballgame here. I don't have a PSI readout on that press, but we'd just jam it in at an angle similar to what you're talking about. I'm definitely running a sharper angle on the new press, and I'm guessing with much more pressure as well. Which I thought would be of help on these jobs, but so far haven't achieved anywhere close to the results that I did on the old press. Its mind-boggling.
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The thing about the v-squeegees that I found is that during your flood stroke, you'd be 'loading' the screen a lot more than a chopper flood bar does. not sure what the correct answer is here as if I did the same as I did with the javelin, I'd be tearing screens.
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Try upping your pressure, that's what we had to do on our new sportsman. Most prints are around 50psi, and once we did that, no issues.
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The thing about the v-squeegees that I found is that during your flood stroke, you'd be 'loading' the screen a lot more than a chopper flood bar does. not sure what the correct answer is here as if I did the same as I did with the javelin, I'd be tearing screens.
That's an interesting point. I wonder if it would actually be better to run a squeegee at a reverse angle instead of a floodbar for discharge/wb. I will definitely be giving that a shot.
Try upping your pressure, that's what we had to do on our new sportsman. Most prints are around 50psi, and once we did that, no issues.
Thanks man, will give it a shot. What squeegee duro/angle/off contact are you running?
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Try upping your pressure, that's what we had to do on our new sportsman. Most prints are around 50psi, and once we did that, no issues.
Agreed on this. 50psi on the Sportsman is like 35psi on the Javelin chopper heads -- (I had mine modified with pressure regulators which IMHO, is quite stupid that Workhorse didn't think of when they made the chopper upgrade).
Interesting that it's so different, but then again, the cylinder bore is different on the Sportsman vs. Javelin, so I can see that 35psi vs 50psi could be a different 'ultimate' pressure.
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Increasing angle and slowing down the speed may help prevent this. Brand new squeegees really bite into the mesh and emulsion if the angle is too vertical. I look at the print process of discharge as "pinching" the ink rather than "scraping' the ink that is common with plastisol. Slowing down the print stroke a little should also help.
Yes you can use a squeegee as a floodbar, works nicely to fill ink well completely and can help back off print pressure. Also helps to preserve the stencil with a softer blade set at a slight angle.
The last trick is to use a bias stretched screen on coarser mesh. Could be a sharp squeegee is catching the threads like speed bumps. Bias stretched screens avoid squeegee chatter, especially on coarser meshes. 150 is not that coarse. You could also use Murakami 150S LX mesh. We fuse the mesh threads at the knuckles and the thread itself is also softer to provide a lower RZ value on the inside of the screen. You can also face coat the inside of the screen to smooth out any mesh bumps.
Al
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Try upping your pressure, that's what we had to do on our new sportsman. Most prints are around 50psi, and once we did that, no issues.
Thanks man, will give it a shot. What squeegee duro/angle/off contact are you running?
We use Smiling Jack Squeegees, straight up and down, typically on contact or one step up from on contact. We use their "white knight" blade
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Increasing angle and slowing down the speed may help prevent this. Brand new squeegees really bite into the mesh and emulsion if the angle is too vertical. I look at the print process of discharge as "pinching" the ink rather than "scraping' the ink that is common with plastisol. Slowing down the print stroke a little should also help.
Yes you can use a squeegee as a floodbar, works nicely to fill ink well completely and can help back off print pressure. Also helps to preserve the stencil with a softer blade set at a slight angle.
The last trick is to use a bias stretched screen on coarser mesh. Could be a sharp squeegee is catching the threads like speed bumps. Bias stretched screens avoid squeegee chatter, especially on coarser meshes. 150 is not that coarse. You could also use Murakami 150S LX mesh. We fuse the mesh threads at the knuckles and the thread itself is also softer to provide a lower RZ value on the inside of the screen. You can also face coat the inside of the screen to smooth out any mesh bumps.
Al
Thanks Alan, all of that makes a lot of sense. And as you suspected, the blades we are using are pretty much new.
I hadn't thought of face coating the screens but will give that a shot as well. In regards to the LX mesh, is there anywhere to get that by the yard or is it only sold by the bolt or in panels?
And while you're here, I'm currently using HVP as my emulsion but have been hearing good things about SP1400 for WB/discharge applications. Wondering what your stance is on the best Murakami emulsion geared toward these inks. Apologies if this has already been discussed before.
We use Smiling Jack Squeegees, straight up and down, typically on contact or one step up from on contact. We use their "white knight" blade
What is this "white knight" you speak of? I got some red Jacks but they have not been knighted.
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We tried the SP1400, and we weren't a huge fan. I know some shops like it a ton, but Brandon had us try the Saati Red PHU and that's working AWESOME. Also Tony had us give the CCI WR14 a try, and that emulsion is amazing.
The White Knight is a yellow blade, very similar to the red smiling jack. Each color puts down a different ink deposit, and the white knight puts down the most in our research so far. It works really well for discharge prints.
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We tried the SP1400, and we weren't a huge fan. I know some shops like it a ton, but Brandon had us try the Saati Red PHU and that's working AWESOME. Also Tony had us give the CCI WR14 a try, and that emulsion is amazing.
The White Knight is a yellow blade, very similar to the red smiling jack. Each color puts down a different ink deposit, and the white knight puts down the most in our research so far. It works really well for discharge prints.
Good look on the emulsions. I've been with HVP for about five years but am looking to test a few others in the new year, specifically for discharge/wb applications.
Out of curiosity, is the difference between the blades the angle of the bevel? And are you getting these from Mr. Clarke himself, or is there a supplier selling them? I've only been able to track down the red ones.
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Yep! we order from joe. the white knights are not always in stock though!
and yeah it's the bevels!
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I hadn't thought of face coating the screens but will give that a shot as well. In regards to the LX mesh, is there anywhere to get that by the yard or is it only sold by the bolt or in panels?
I know it is not exactly close to you but these guys sell the 150LX and 180LX by the yard.- www.nwgraphic.com (http://www.nwgraphic.com) I have some too I could send you if you want. To each their own, but the only time we will use the 150LX for discharge is on hoodies. I know there is minimal difference but we found for us the 180S or 180LX leave a much softer hand.
You got much more intelligent responses here compared to my mumblings yesterday! ;D
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I'm sure all of these suggestions are valid but we do not use special mesh or squeegees. Could the Charleston climate which year round is either damp or humid.
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SP-1400 is an economical diazo emulsion for all ink systems. Being a diazo emulsion it needs a little longer exposure. If you have high volume screen production go with HVP plus diazo. It is worth noting you can add 8 grams per gallon, or double it to 16 grams per gallon for added strength. On 5k+ systems this often means you will not need a hardener. We also have 2 new emulsions, Murakami T3, no hardener needed for dc and wb and Murakami TSR for High Solid Acrylics as well as dc and wb. Too many are referring to high solids acrylics as a water base ink. It is a co-solvent ink, so it requires different emulsions. For discharge however a good exposure works wonders on either SP-1400 or HVP.
Happy New Year everyone, lets rock 2015 and all have our best year ever.
Al
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I know it is not exactly close to you but these guys sell the 150LX and 180LX by the yard.- [url=http://www.nwgraphic.com]www.nwgraphic.com[/url] ([url]http://www.nwgraphic.com[/url]) I have some too I could send you if you want. To each their own, but the only time we will use the 150LX for discharge is on hoodies. I know there is minimal difference but we found for us the 180S or 180LX leave a much softer hand.
You got much more intelligent responses here compared to my mumblings yesterday! ;D
I didn't see it on their website, but will give them a call. Any chance they sell S-Mesh by the yard in counts other than what River City carries?
And your "mumblings" were some of the best info I've received on the subject! I even took notes!! ;D
I'm sure all of these suggestions are valid but we do not use special mesh or squeegees. Could the Charleston climate which year round is either damp or humid.
Funny you should say that. I printed discharge without these issues for years using 158 statics at 12-15N with a 70 duro blade on a press without pressure adjustment or the ability to adjust off contact. Maybe its time to get back to basics. On the subject of humidity, we certainly aren't lacking that in Fort Lauderdale. :o
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You can order any of our meshes through our distributors and have it dropped shipped to your location. This helps the local distributor see demand so they will stock it. So many meshes, it's hard for a distributor to stock all of it. LX Mesh is often not stocked by dealers, but it works well.
A couple of print techniques for discharge:
1. Try using a slightly thicker stencil. This helps hold more ink in the image area to transfer. 1 additional coat can do wonders, as can face coating print side. For durability face coating squeegee side as well and upping the exposure time also helps.
2. Try on contact printing. A flooded screen on contact will start to wick into the fabric before the squeegee even makes the pass and the fabric will have time to soak up more discharge.
3. I liked a worn 70 durometer with a rounded edge at 5 degree more angle. I would often save the worn plastisol base plate squeegee that couldn't cut plastisol anymore and use it for discharge and wb. Watch for nicks though, they will affect the print.
4. Angle: Most shops never change angle of squeegee, yet this is crucial for discharge IMO. Bright color comes from loading the shirt fabric. A fast moving vertical squeegee used for plastiosl overprints is nowhere near the quality of a rounded edge squeegee with a slightly slower squeegee speed with more angle. Go ahead and crush the print with plastisol squeegee settings to drive it in, but this is best for short runs. Long runs benefit from more angle and ever so slightly slower squeegee speed. Slowing down the flood so it completes it's pass just as the head drops or pallets raise also helps fill the image area with a more complete load of ink. You can still print fast with just slight adjustments of speed.
5. Localize your inks. By that I mean use ink dams made of tape on all four sides of the squeegee path. This limits the inks exposure to air which can lower the discharge effect and cause color shifts. Run with a full blade of ink at all times, also keeps activators in balance with the bases, controls color well. We had ink personnel who added a drop of ink about every ten to twenty prints who would simply walk back and forth over three presses to maintain ink levels. Localizing ink also prevents dark ink ribbons in the open areas of the print when ink is pushed back into the print area after sitting exposed to the air.
6. Pillow flood higher mesh counts so you can't see the image. On lower mesh counts with S mesh you may not want to pillow flood and leave a pile of ink on top of the image since it can drip through. But for 180-225S it can help pop the color more.
7. If you see stripes in your print it is a mesh/shirt fabric interference pattern. Consider going to a 22.5 degree bias stretch, or to the next S mesh count up or down. Sometimes I have seen this with hard squeegees and too much squeegee pressure as well.
8. Put a flash in the last head. This allows the unloader to catch pinholes that discharge faster than solid areas of discharge.
9. Use a black sharpie to cover discharge pinholes on black.
10. Only activate what the press can print in an hour. We used master buckets of color for long runs. keep a quart container by each color. Activate a quart with pre-weighed activator in plastic cups with plastic wrap and a rubber band over them so it stays fresh. When quart runs out, scoop out another quart, leave a 1/2 inch from top, add pre weighed activator, mix and add a drop every ten to 20 shirts. We also set up hand pump dispensers zip tied to the press so it put a drop in every time it printed and a long tube into the activated quart that sat in a welded cup holder on the head. Takes some fine tuning to position the pump and locate it so it doesn't pump out on the image. We only did this on 20k runs or higher.
Perhaps the craziest thing we ever did was a run with large cookie trays of different fluo discharge colors and a bunch of different tires like small bike tires, car tires, all with crazy tread patterns. Roll the tires in the inks then roll them randomly over spray tacked black shirts adhered to a clean floor. 3x3 set up of shirts on the floor to do nine at a time. There are spray tacks for the shirt to floor as well as different spray tack on inside of shirt that keeps it all flat. Some of the coolest prints were tires that didn't make it across and spun down on the shirt. This idea came from a Hendrix song lyrics of 'tires tracks all across my back" and maybe a few beers. The mess, is well a big mess. When the trays are running out of inks you can take spatulas and brushes and fling the ink across the shirts as well. Charlie Taublieb has tons of more cool effects with discharge if you can ever take one of his totally t shirt seminars at SGIA.
See you all at ISS for those coming.
Al
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All good tips Al. We keep 50 duro sharp blades around they can do wonders. Medium to low tension. We now know how to stretch activated inks up to 10 hrs but have master color kitchen with about 80 colors kept in gallons and activate as needed with little waste. New color recipie books almost finished
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These were always fun. Found a way to keep the mess to a minimum using transfer paper
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Ummm. Sweet info. Thanks...going out to the shed right now to get an old bike.
Murphy37
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One more crazy trick we tried. Wash the shirts in a washer. Stop at spin cycle. take Ketchup bottles and squirt multiple colors of discharge on them while they are in the machine. Start spin cycle. Not recommended, but you can push a pencil in the lid to keep spin cycle on and spray some more. Craziest looking shirts ever. with subtle tones and bright highlights if you spray at the very end of cycle. Curing is a pain though, ten passes through the oven and we had a 20' gas oven with electric panels in and out. We experimented with spininng them twice, which got a lot of water out of the shirts and made more vibrant areas. Run many cycles afterword to avoid the wife confrontation however when her clothing gets fades marks all over. The things I have put that poor woman through.
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Wow, awesome posts Alan. Thanks for taking the time to write all that up, it will definitely be going to good use in my shop.
As an update to my original post, I seem to have solved the issue one way or another. I'm not exactly sure what exactly it was as there are so many variables involved, but I'm leaning toward an old batch of activator possibly being the culprit. In any case, the following changes were made:
New batch of Matsui Discharge White
New batch of Matsui activator
Added 3% Rutland Penetrant
Added 3% Rutland Lubricant
Increased burn time by 85%!
Much more liberal use of hardner
Changed blade angle from 12 to 18/19
Increased pressure from 40 to 50psi
Moved pallets in toward the press
Moved image further down the pallet
Brought off contact a bit tighter to to .05, which feels pretty much like zero with a shirt on the pallet
These changes were all made on Monday and we ran discharge for two days straight without a hiccup, up to 200 pieces per run. Thanks to everyone who wrote here and contacted me privately to help with the situation, it is GREATLY appreciated. I can't thank you guys enough, this forum and its members are the freakin best.