The Importance of Speed and Pressure

[alan802]

I hope these pics translate like they do in person, but I had a chance to do some testing yesterday and I was specifically testing some blades using One Stroke Production White which isn't a very fast shearing ink but I didn't want to switch out the ink because we were on lunch break from a larger run.  I used the same blade and between these two prints, I changed the speed and pressure but the pressure was added only to help shear the ink at a higher speed.  So the top print was printed at 25"/sec at 25psi.  The bottom print was 4"/sec at 20psi.  Now for clarification, if the ink would shear at 25"/sec at 20psi, then it would be better than 25psi, but you have to find that line where the ink shears and the pressure isn't too great so that it penetrates the garment.  I just wanted to share this and open a discussion on it since we've finally gotten back to normal around here and I have time to breath and talk about stuff like this.

Looking at the pics it doesn't really do the difference justice but oh well, it does show enough of a difference in opacity.  In person it's close to a 40% difference in opacity but it doesn't really show that in the pics.

[alan802]

I'm going to try and take better pics, this is bothering me looking at the shirt in person then looking at the pics.

[jsheridan]

I can tell one is smoother.

That sheer point is tricky and contains multitude of factors.

I put the ink in the screen room the other night so first thing on a cool morning the ink was at 80 degrees.. into the screen and printed like buttah

this morning shop in the 60's and OP is having a heck of time to get the ink sheered and smooth.

Are you using a roller squeegee or any kind of after flash smoothing screen?

[alan802]

I tried the roller squeegee and it did very little for us.  It certainly wasn't worth the effort to mess with that extra screen even if it is fairly low maintenance.

The top print is not all that smooth as I was using a poly ink and pushing it to the edge with speed, but opacity wise, the top is way more opaque and getting it smooth is a matter of dialing back the speed a few inches per second or using a shear friendly ink.  With a better shearing ink I could do that print as a one hit white on a decent garment.  If I got that opacity with an ink that isn't ideal, I know under the best circumstances I can get 100% opacity with one stroke.

[alan802]

Ok, let's see if these are any better.

[alan802]

Some of you may recognize the shirt it's printed on, one of my least favorite, beefy T, which makes getting a little more ink on top of the shirt that much more important.  There is nothing worse than a hairy substrate and penetrating ink into that type of weave is asking for trouble after the first wash, and then it gets worse from there.

Most poly inks HAVE to be printed slow, and this ink is only a little better than most poly inks which makes a difference when pushing the speed and pressure limits.  If I were to put Tidy white into this screen I could have printed at top speed with about 20psi, and if our press would print faster than 30"/sec then we would likely get even more out of the combination.  I printed the faster print first then all I did was lower the pressure to compensate for the slower speed then pulled the first image off the pallet and printed the second.  I didn't change the angle or squeegee and there was only about 15 seconds between these two prints.

[mimosatexas]

Interesting thread, and a topic I keep seeing pop up in other threads.  Today is actually a little slow for me so I decided to use a small run this afternoon as a test.  I am a manual printer as most of you know, so this isn't exactly apples to apples, but it was interesting.

I usually p/f/p my whites using a 180S or 225S.  I use Triangle Poly Excel for almost all my white prints on 100% cotton and 50/50 which is 99% of what I print.  It works great on both and is the easiest to work with white ink for printing manually I have ever found that also has bleed resistance, good mat down, doesn't fling all over the place, etc.  I am really liking some of the One Stroke whites, but haven't thoroughly tested them enough to switch.

Anyway, back on topic...I decided to test my standard p/f/p with 225S coated 2/1 sharp with SP1400 (slowly becoming my go to for anything that isnt low mesh) vs a double stroke no flash using a 135S coated 2/2 round with HVP.  The 225S I soft flooded and stroked at my normal speed and pressure which gives me the best control etc.  The 135S I stroked as fast as I could and as light as I could with minimal pressure.  It made it hard to keep everything consistent, and there are some edge definition issues as a result, but still acceptable.

Opacity-wise the prints are both basically perfect.  I'm not sure if the 135S would be considered a true one hit white due to double stroking, but it is definitely a no flash white.

The final look from afar is great, but I did notice a huge difference in the actual texture of the ink, shown in the photos below.  The 225S p/f/p is MUCH smoother, like night and day.  That alone would keep me from switching methods currently.

Just thought I would share...

edit: both photos are zoomed in as close as my cell phone would take them, then cropped to the area with the best focus, and edited to be darker than reality to highlight the texture.  Just FYI.

[alan802]

For clarification if needed, we would PFP this job. I'm not saying this is a one hit white or really that close.  I'd say the top print is about 80-85% opaque, which would put it far from the accepted 100% opacity, which is subjective of course.

[sqslabs]

Nothing to add, but great thread!

[Prosperi-Tees]

Alan, do you still have the roller squeegee?

[ZooCity]

Texture of the print is a buzzkill with the 135 coated thicker. 

That mesh can drop so much ink onto a shirt that you could one stroke, one screen everything if you build a thick enough stencil and deal with the texture of the cured print. 

The edge definition issue is surmountable with perfect everything on the print head but would really require an auto, a pretty well cared for one, to achieve regularly. 

[alan802]

Alan, do you still have the roller squeegee?

This guy I barely know that keeps me on my toes let me borrow his one day while he was passing through town and we set it up on the press and ran a few jobs.  It was noticeable on one print where we were using a poly white ink for an underbase but for the other jobs it really didn't offer anything of significance.  I see the huge group of great printers here using them and I keep wanting to try it again to see if anything has changed but honestly our prints now are brighter and smoother than they were when we tested it.  My thinking is if we didn't get decent results then I don't think there will be anything different this time around.  But like everything else, I'll keep on testing and trying to make us better in any way I can.  If anyone wants to send theirs to me for a week or so to test out I'll send you a squeegee blade to test out for the same time period. Email me.

[jsheridan]

talk to Eric at Action alan... you want the roller.

[brandon]

Hey, so work with me here on this question with an open mind.

I have a friend that uses the roller on water base / discharge prints.

We are mostly water base / discharge and now some HSA inks in there as well. Any plastisol has a clear discharge base. All prints are smooth

Anyone else using the roller on water base?

[ericheartsu]

we more or less use a roller for almost every base, plastisol or discharge