300S versus 305 for simulated process?

[Screen Dan]

Someone mentioned 300-40 (300-HD)...I have no need for that kind of ink control now that we have all of our other factors dialed in pretty good but I just have to say that 300-HD is a goddamned tank.  That mesh is in fact rather heavy duty, as the name implies.  I have never seen such a high mesh count hold tension (and even be retensioned successfully, repeatedly) with such giant holes in one side or the other.

I rarely replaced those when we used it.  Amazing stuff.

Okay, didn't mean to derail.

[ABuffington]

Hello everyone, Al from Murakami here.

1. The difference between our 300T and a 305 from other manufacturers is a conversion issue from metric to our system of measurement.  Thread counts listed on the bolt are how many threads per inch the mesh has before it is tensioned.  Depending on the 'elasticity' of the thread this changes after taking it up to tension.  It is no longer a 300 or 305, but slightly less per inch.  So depending on the elasticity of the thread you could have more or less threads per inch.  Smartmesh has less elongation than any mesh, it reaches tension far quicker and may have the same or a few more threads per inch depending on the tension level stretched to.

2. 300/34 = 300/T There is no S mesh in 300.  The next up is 310S, which I don't recommend for textiles, basically for Industrial Printing needs.  330S and 350S are two meshes that are often used in place of 300/T in textiles.  Moire is a little easier to control with more threads, but the big plus is they are less fragile.  350S also is thin enough that you can use 20 micron stochaistic and get excellent definition.  350S is my go to on our show shirts.  It puts down just the right amount of ink to avoid dot gain or too much ink in a fine sim process print.  I use 225S bases with 350S for color, plastisol,  225S for all color in discharge and wb halftone work, and 135/S-150S-225S for HSA.  I also like 300/40 or 300/HD for automatics.  Halftones do need to be curved and tonal range compressed a little on both ends, but 300/40/HD can withstand 30-35 newton tensioning which helps in plastisol printing for say a highlight white right after a flash.  The higher tension helps peel off on hot tacky surfaces, especially on designs with solid areas in the base plate and halftones. 

3. S-Mesh from Murakami uses our proprietary thread.  It resists elongation which keeps the screen at a workable tension on statics, on press it resists accumulated elongation which is caused by the squeegee warming up the mesh and stretching it causing loss of tension, but more importantly, loss of registration.  I highly recommend Shurloc panels for Newman Rollers, much less breakage since the mesh rests on the Shurloc strip and not the sharp edge of the channel which can have nicks and dents.

4. Totally agree on not flooding sometimes to avoid dot gain.  I use this technique a lot on faces where I want to have smooth tonal transitions.

5. On  S mesh or higher T mesh counts, round off your squeegee ends as smooth as you can.  A square squeegee end is like a knife going back and forth.

PM if you have any questions on our pre-stretched screens, re-stretching services, or articles on how to handle, stretch S Mesh.

Thanks
Al

 

[JBLUE]

Wow, big thanks to everyone for helping out with this.  It's been really enlightening!  River City's website has actually been changed now to reflect the difference in thread size.  Got everything ordered this morning, and it was good to talk to Kevin for a few minutes.  Can't wait to try out our new screens, ink, and squeegees.  Bought five 70-90-70s in aluminum handles for our top colors, and a bucket of Triangle Phoenix White.  A smart guy would change one variable at a time, but I know I'm doing too many things wrong at once to not be impatient about it.  Fun stuff!

I would change the Triangle ink out at the same time. Get a double bonus doing that too.......

[andyandtobie]

Not a fan of Triangle?  What's your preference, if I might ask?  The only white plastisol I've had so far has been QCM 159, and I have a hunch that we're victims of the batch inconsistency that people have reported here about 159.  We heated it up to 90 degrees and drilled it like crazy, and it was, well, "okay."  Even through a 150-S, it didn't seem like it really wanted to go through the screen all that well, and we had some pretty serious texture.

Again, huge thanks to everyone who has posted to this thread.  Amazing how much you can learn here in such a short time from you guys!

[Screen Dan]

Not a fan of Triangle?  What's your preference, if I might ask?  The only white plastisol I've had so far has been QCM 159, and I have a hunch that we're victims of the batch inconsistency that people have reported here about 159.  We heated it up to 90 degrees and drilled it like crazy, and it was, well, "okay." 

...we had our QCM rep and one of their techs out to check the ink.  I was told months ago to "do something" about my screens.  Nothing was wrong with any other color except the white but I accepted the challenge.  Upped our tension standards further, increased retension frequency, played with EOM between 25% and 300% higher, experimented with chemistry, trashed certain screens...blah blah blah blah blah....to the point where I said "it has to be the ink" ...and I'm not one to point blame or give up in the face of a technical challenge.  I was head operator on that floor for over 7 years, it's not like I have no experience with that kind of stuff.  I've probably printed over two million shirts, maybe twice that...maybe quadruple that (we weren't that big into analytics back then).

So I threw my hands up, they brought the tech in.  He asked me a bunch of questions, rather detailed in nature...come to find that "some batches" of this QCM ink has some particle size, I'm assuming its PVC, that was inconsistent throughout some batches.  Therefore if your minimum feature size was around as big as the maximum particle size (or anywhere close, probably) it would very quickly hang up in your mesh.  (45LPI had no problems, 55LPI did, 60LPI wasn't worth the effort)  After a round or two on the 14 color you'd have to stop and wipe down the white.  Sometimes even worse than that.  This is through 150-S and 150-LX...yeah, it was that bad.

It drove us nuts.  It appears to be all taken care of now...but that was going on for years and got especially horrible in the past couple months.

Seems fixed now though.

[andyandtobie]

Dan, thanks a lot for posting your experience, it explains a lot.  As I think I've mentioned before, I've only run waterbase up until recently, and 159 is the only plastisol white I've used so far.  Your experience with it sounds almost exactly like what was happening to us.  We're set at 50LPI, which I'll bet is just enough for this to be a problem.  We would print a few shirts, they would look great, then we would start to get blobs of buildup that would ruin the print until we wiped the screen down and cleaned it.  Then we would print a few more shirts until the blobs started building up again (and ruining more shirts).  That's the biggest reason why we've been back to all-waterbased for the last six months.  I'd assumed it was a case of too open of a screen combined with the wrong squeegee, but now I see that that obviously has nothing to do with this problem.  Maybe we'll give 159 another try later, but I feel like I should try other whites for a year or so until the old 159 has a chance to move through the supply chain. 

[Screen Dan]

Maybe we'll give 159 another try later, but I feel like I should try other whites for a year or so until the old 159 has a chance to move through the supply chain.

That sounds wise.  We only switched to QCM to go phthlate free, and it was the cheapest option to do so.  From the couple of times I screwed around with it on press while doing R&D I was not thrilled with the white's performance...and this is before it started becoming a problem.

My favorite white to print with is a tossup between Street Fighter and Buffalo...though I recall Buffalo having a very strange flood that you just couldn't get to cover evenly...like craters where there would be no white.  Printed great though.