# ink bubbles on the screen



## JimBo_B (Sep 25, 2018)

Long post. My apologies in advance.

So, I just started with the screen printing (How many posts in this topic start with that!) and I am having some major issues with printing white ink. Unfortunately, after a few hours of searching, I have not found anything similar in a post, so I figured I would create a new post.

Description of problem: 
Bubbles. All along the edges of my screen (see attached picture) after 2 to 5 prints. Also caking on the shirt print (ink sticking to screen) when using white ink, Green Galaxy Comet White.
It manifests itself on the shirt as fuzzy edges.
After cleaning the screen out, I can print 2 -5 more times with great looking images. (it appears that the emulsion is not deteriorating)

https://i.imgur.com/VvVC11l.jpg
The bubbles are on the outside of the image area.

The set up:
Riley Hopkins Jr set up
156 mesh screens
WBP emulsion (emulsified on both sides of screen)
UV light exposure unit
flash dryer
(The screenprinting.com semi pro set package)
All about 2 months old

Methods:
I have tried print/flash/print,
print/reprint on wet, 
print/cure/print, 
print/wait/print, 
and print really hard. 
All with little to no change.

Screen set up:
I have tried zero off contact, 1/2 inch off contact, 1/4 inch, 1/8 inch... etc. with and without washers at the end of the screen to maintain off contact. These changes changed the amount or prints I did before the bubbles appeared, but I have not been able to do more than 5 prints before it looked rough.

Technique: (where I suspect the problem is)
I have gone with a light touch with multiple flashes and prints (it works with spray painting, why not shirts? ) This gave me the best results, 5 good prints in a row. (3 good, 2 good enough)

Pressing down and really pushing the ink into the shirt. This seems to accelerate the bubbles. I get one good print, then fuzz on the next shirt.

I have also tried about every conceivable pressure and angle combination possible with no major changes.

I have the same results on large prints as I do small prints. Although the bulk of the experimentation has been on the MIKE print to maximize my attempts over a given garment.

I have done quite a few black ink on white, and blue ink on white with no problems but of course, that is an entirely different kind of ink altogether (its and entirely different kind of flying...)

Additional info:
I'm in a garage in FLA. But I do have an AC running. its probably 80 to 85 in there when I'm working.

I've seen a few videos on the you tubes, but nothing has come up directly addressing this issue. (the caking yes, but not the bubbles) There may be a video out there addressing it, and if you know of it, TIA for sharing!

I think that's about all the info I can get out there. If anyone has ANY tips whatsoever I would be most grateful.


Thanks!
Jamie

https://i.imgur.com/VvVC11l.jpg


----------



## shogren (Oct 2, 2018)

Have you tried printing on some newspaper after a few shirt runs? You could be getting some fuzz or debris from the shirt stuck on the backside of your screen. 

White is particularly sticky, so you could be gathering some artifacts on your print side. Do a couple pulls on some cheap paper to clear it out.


----------



## TABOB (Feb 13, 2018)

JimBo_B said:


> Pressing down and really pushing the ink into the shirt. This seems to accelerate the bubbles.


You've partly answered your own question.
You are definitely using too much pressure on the print stroke, and probably on the flood stroke as well. So you are pushing ink out, and then "crushing it", so it has nowhere to go but sideways.
Try this:

1. Food by barely toughing the screen.
2. Print with the minimum pressure possible, and use 2 print strokes if needed.
3. If you print-flash-print you need even less pressure.


You will still get this issue eventually, but you should be able to print a lot more than 5 shirts. Sometimes I can print 300 without problem, and sometimes I have to clean the screen every 50 prints. This is normal.


----------

