problems with underbasing

[Shanarchy]

From time to time I still have trouble with underbases. Printing manually, I lay down a pretty white/smooth first print. Sometimes I have a lot of trouble getting the top color to sit nice on it. Where you can still see tons of white dots, or the color isn't consistent (high and low shades). If I p-f-p the top color, the color is solid, but the print becomes too thick and shiny. Can the ink I'm using for the top color make a big difference? Last week I printed pink over a white underbase and it looked perfect. It was a Miami Ink HO color. It wasn't a super opaque that you could p-f-p without an underbase, but more so had better opacity. The ink I'm using now is a WM Plastics royal blue type shade. I'm not sure what it is (special mix), but I'm guessing it is an AP ink.

Are AP inks not ideal for printing over an underbase? Am I missing something obvious here?

Thoughts? Suggestions?

[Printficient]

This is a heat issue.  The first example of white dots is too much heat.  The second is not enough heat.  A "flashed" ink should feel like paper not sticky.  Also look at stroke speed and pressure.  Ink pushed into the garment competes with said garment for heat in flashing and curing.  The object is to lay the ink "on" top of the garment.  This is done with proper mesh, squeegee, and ink selection among other parameters like press level, off contact, etc.

[Shanarchy]

Sonny, do you think I'm over flashing my underbase? I don't think it's under flashed. I can touch the ink with my finger and it won't come up.

I should add that I'm printing these on a manual.

[Inkworks]

Off contact of your top colours is a big factor in how they go down too. Printing on a flashed base should be easy-peasy and clear in one stroke nicely, even on higher mesh counts.

Flash just enough so the base isn't tacky. Overflashing can cause fish-eye in the top colors during the trip through the oven.

[Printficient]

Sonny, do you think I'm over flashing my underbase? I don't think it's under flashed. I can touch the ink with my finger and it won't come up.

I should add that I'm printing these on a manual.

If it is tacky or sticky to the touch, then yes.

[alan802]

Sonny, do you think I'm over flashing my underbase? I don't think it's under flashed. I can touch the ink with my finger and it won't come up.

I should add that I'm printing these on a manual.

If it is tacky or sticky to the touch, then yes.

I'm going to disagree with Sonny on this one and I don't have much time to go into what I think the issue is right now but when I get a chance to sit down and type it out I will come back to this.  I don't see those characteristics, especially the UB poking through the top color, being caused by excessive flashing, just my opinion.  Other things cause those problems here at our shop, starting at the foundation/underbase.  Any imperfections in your underbase will be seen with your top colors. 

[Socalfmf]

It is because you are printing. Again you should not be worrying about that

Sam

[Dottonedan]

I imagine it like this. The base is on a pretty low mesh and your underbase white ink is thick. Add to that, the top blue ink (sounds thin). This could make your white halftones protrude thru the blue. With big dots on underbase and low mesh(causing a raised edge) and a over flashed base, cause it to really show even thinner since only a very thin layer of blue ink sits on top...and your blue ink falls to the shirt color on the outside of those dots. This makes the white dots seem to stand out even more. Your squeegee is scraping the blue ink coverage off of the mostly cured white dots.

Remember that a white underbase is only intended to be intense enough to help that blue maintain is true hue. If the blue overprints everything...you do not need a bright white lay down. For example, sometimes I use a 305 mesh as a white underbase with no halftone. Less ink, fast flash.

That's how I see it in me Lil head.

[Shanarchy]

I underbase with a 110. I print stroke followed by a dry stroke to make sure the print is flat and smooth. Then I flash. Top coat through a 160.

I know my mesh counts are on the low side, but I honestly do no know how people are (manually) printing white ink through high mesh counts and clearing the screen without killing their bodies.

The area in question is pretty much a solid 7"x 7" square. I'm sure that is not helping.

The underbase is not halftoned, but the topcoat has tons of white speckles still showing through the ink.

I tested and made sure the underbase was just brought to a proper flash. Not over flashed, and not anything being picked up on your fingers. I waited 2 minutes to make sure that pallet was nice and cool. Still having the same issue.

Obviously it must be something I'm doing, but not sure exactly what.

[Dottonedan]

Post up a pic of the art.  Do you have higher mesh?   What are the tensions like?

Your troubles printing on a manual are connected with your mesh, the inks and squeegee blade type.

Thick inks and low mesh make for clearing g the screen well.

Thin inks and high mesh make for clearing the mesh easier but you do need tight screens and the right inks. Hard squeegees help cut the ink. Softer squeegees wi sort of "mash" the inks thru to put it in basic terms

Higher tension, higher mesh, low off contact, thiner inks (inks designed fir high mesh) and sharp hard duro squeegees (like a 70, 70/90/70 an 80 or even a 90 with an almost verical angle to start...make for good manual printing ( for my recipe). I don't print in house yet, but that's what I suggest to many and they end up with great prints.

I know I'm reaching outside my bounds since I don't print yet myself, but for what it's worth, it works for others I've suggested to.

[GaryG]

I'd hedge to bet the 110 may seem smooth, but either of these can be happening:
-Any blowing agent (puff) in the white? The knuckles of a coarse 110 are making peaks,
with or without raising of UB.
-Not enough pressure on the blue. I've seen specks showing if not enough pressure,
or hit it twice without flashing, just to cover smooth.

Try a 125 or 156 to let the UB be smoother.
It will still print easy on a manual.

[screenxpress]

I always use a 156 to 160 for underbase.

[Shanarchy]

Dan,

I just checked the tension of the screens in question. The underbase is at 20 and the top ink is at 24. Both way lower than I'd like to admit. Looks like it may be a good time to go trough all of my screens and retension them real soon.

Squeegees are triple duro 70/90/70.

I'll get you a pic of the artwork in a bit.

Gary,

I'm using Miami Superior white. I don't know if there is a blowing agent in there, but it's not very noticeable if there is.

I don't think there is a pressure issue with the blue. The ink is clearing the screen. But I can always try to give it more pressure to see if it makes a difference.

I may get some 125 mesh to try with white and see how that differs from the 110. I also need to try underbasing with gray at some point.

[Shanarchy]

I always use a 156 to 160 for underbase.

Wayne,

You print manually, do you find it a struggle getting the white through a 160?

Something I've wondered recently is the rubber top Vastex pallets. It seems to be a different type of rubber than other pallets use. It seems softer (could be my imagination). Could my printing surface be softer than other presses (hard wood, standard rubber coated aluminum pallets)?

[Frog]

Shane, I am old and weak and print manually (push stroke on full size) and have almost eliminated 110's (at least for regular opaques)
I do not use retensionables.

I did switch to almost all 160's, and most cotton or low bleed inks print pretty well. These are not your father's inks nowadays.

That said, I did recently get some frames re-meshed with 140 and 125 for when I need a little more ooomph.
(a fleece only job will probably see the 125's)

Now, if you are having trouble with your white through a 160, you may want to put the whack on it (in it)
It will be smoother, easier to clear,  and as an underbase, a slight reduction in opacity probably won't matter