Discharge Woes

[sqslabs]

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. 

[jvanick]

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.

[sqslabs]

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.

[jvanick]

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.

[ericheartsu]

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.

[sqslabs]

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?

[jvanick]

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.

[ABuffington]

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

[ericheartsu]

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

[sqslabs]

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.

[ericheartsu]

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.

[sqslabs]

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.

[ericheartsu]

Yep! we order from joe. the white knights are not always in stock though!

and yeah it's the bevels!

[TCT]

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 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! 

[tonypep]

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.