[rustyhill]

Greetings,

I am not new to screen printing or this forum. I just do not use either enough to be an expert. I have no trouble with water base inks and printing on fabric. Unfortunately, the Nazdar 9700 ink series has caused me a bit of trouble.
Here is what I am doing:
I am using a m&r chameleon manual press. The screen is a 230 mesh count which I am applying a 2:1 application using the sharp side of the trough. The emulsion is IMS 905 Image Star. The screen looks great after exposed and dried. The substrate is a clear overlay plastic binder. I am adding NB80 Adhesive promoter (10%) to 9700 ink. I keep it simple and just do 100 grams of 9700 to 10 grams of adhesive promoter. I am having problems after the first binder where the ink will dry in the thin lines of the artwork in the screen. I am also flooding the screen completely right after the print. In the attachments I have 2 pics of the 2 binders I printed. binder 1 is the good print and binder 2 I started loosing detail under the building and ink started to fill in the vertical lettering on the right. Please help!

 

[JeridHill]

The problem with reverse prints like you are doing can be fixed, but there are several things to consider.

1. Flood Coating: If you do flood coat, you need to cut it sharply. Do not let the ink pile onto the screen like you do in plastisol inks.

2. No Flood Coating: If you do not flood coat, you need to work quickly. Typically with a reverse print, I printed with no flood coating, but the conditions are:
a. Work very fast
b. Keep your inks thinned down, in order to do this, you can put a thinner in a spray bottle and when the ink begins to thicken, spray a couple of mists over the ink and it will work itself in when you are printing.
c. Flood coat in between every 4th or 5th print. This keeps the ink flowing in the thin areas, but does not build up in the areas you don't want it to.

Good Luck....

 

[rustyhill]

I also forgot to mention I have purchased Care 53 slow retarder from Nazdar, but not used it yet.

Also I purchased Kiwocol Poly-Plus S for a stronger more durable emulsion for this detailed artwork. I personally don't think I need it, but it is just another option.

Do you think I need either of these?

 

[JeridHill]

The retarder can help if you aren't working quick enough and it's very humid, but I never really used it, instead I just made sure the ink stayed thin by spraying a couple mists of thinner when needed.

 

[rustyhill]

What type(brand) of thinner do you use? And when you say work quickly how many seconds between each print? I have to print on 100 of these binders so is it possible to make it to the end of the job with these methods?

and thank you so much for your quick response!

 

[JeridHill]

I used the thinner they sold for the ink. If you call tech support, they will tell you what it is if you need it immediately. I don't remember what I used, but they are pretty open with the info. As for how quickly you should print, 3 to 4 a minute is ideal and with the methods above, you shouldn't have a problem printing the job. I've done much larger runs.

 

[rustyhill]

the pic I just sent was what started happening after about the 20th print. Is that just ink that possibly ran through the artwork and got on the other side of the screen? Could it be the ink breaking down the emulsion. Tech support said that is possible and I might have to buy a more durable emulsion.

 

[JeridHill]

Are you spraying the screen with the thinner? If so, it looks like it's too much.

 

[rustyhill]

No I didn't use thinner, but I had it ordered and it should be here tomorrow for me to try.

I tried the Care 53 slow retardant 5% weight mixed with the ink. I thought it thickened it up, but it does still seem thin. I have had this issue on the binders before and forgot to post the pic.

I also wonder if its my off contact. Its possible that I have the screen too close to the platen. It seems like there is too many variables. Our sales rep from Nazdar thinks the emulsion might be deteriorating in those areas and thats why she recommended the solvent resistant emulsion I mentioned in the earlier post.

Have you ever had this issue?

 

[JeridHill]

Any time I've ever had this issue, there was too much moisture or it was too thin on the edges. Are you flood coating at this point or are you just printing straight?

I don't believe it's emulsion breaking down, if it were, the edges of the lines would not be crisp.

 

[wormil]

In the sign shop we used quite a bit of thinner and added it right to the can of ink, 9700 doesn't suffer from it the way fabric inks do. Keep doing the flood stroke though and anytime you stop for a minute, wipe down the bottom of the screen.

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[rustyhill]

thanks for the replies,

It is fairly humid, but we haven't had any issues before until we started using the the 9700 series. As far as too thin on the edges when I printed on the binder, the building in the pic was vertical so it was dead center of the squeegee. Hope that was what you meant by too thin on the edges. I am still flood coating after every print, but that was yesterday. Figured I would try printing 3 to 4 times and then spray the thinner that just came in this morning. I agree on the emulsion though.

So if you are saying you had this problem before then how were able to possibly thicken the ink? I don't know if I can adjust the moisture without turning several fans on.

 

[JeridHill]

It could also be a pressure issue. Where it's blurring, is that what you print first, then the middle, then the bottom is blurry as well? If so, do you have it built up so it's stable underneath or are printing on the flat prior to having rings. It sounds like you are printing finished binders??

You will notice a pretty big difference with these inks compared to plastisols.

 

[rustyhill]

wormil,

what was your ratio for the thinner when mixing it with the 9700 ink. All my can sizes are 1 kilo.

Oh and how were you cleaning the bottom of the screen? The mineral spirits I have been using played no effect in removing ink from the bottom of the screen. It actually just smeared and dried.

 

[JeridHill]

If you clean the bottom of the screens, you will need to make sure there is absolutely no chemical residue on it, or you will get the same issue you are having now, except everywhere and not just one spot.

 

[rustyhill]

the building is the last thing that gets printed which is 2-3 inches from the edge of the screen. After I (pull) print the ink basically wants to flow back into the screen right where the end of the building starts. I am pretty sure its a finished binder. When I am printing I use a good bit of force, but when I hit the crevices where the front and back fold it throws my pressure off ever so slightly.
here is an illustration.

 

[rustyhill]

Oh I am not having any trouble with the front. It starts several inches from the top of the frame. It looks great every time. Hopefully by the illustration you can see that it is just plastic with nothing else attached such as the rings or mounts. I have the binder laying flat on the platen. The platen is pre-sprayed with adhesive so the binder will hold in place.

FYI, the first thing I do: I print directly on to every platen (which has a paper covering) and flash it. I use that as my templates.

 

[wormil]

We used a 50/50 mix of xylene and acetone as a thinner and screen cleaner, no fixed ratio, just eyeballed it but we were pretty liberal. Just remember that solvent inks are going to dry in the screen no matter what, high or low humidity, so you'll need thinner for sure. And if you leave the can open it will thicken so keep the lid on.

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[srking]

Hi Rusty,Your problems with the ink drying into the screens is fairly controllable.
1) As you stated a Retarder will help keep your screens open. , You say you got the Care 53 and that will work just fine or you can use the 9731 retarder made for the 9700 inks. Add up to 10%.
2) Remember to control the air-flow around the print station to prevent ink dry in. Anything that creates “air movement” will accelerate the evaporation of the solvents. Fans, air-conditioners, heaters, swinging doors, open windows, etc.Just don’t forget to keep enough fresh air to manage the fumes.
3) A finer mesh count (305 tpi for example) will result in faster screen dry-in than a more coarse mesh (200 tpi for example). If your application and image allows try a coarser mesh.
4) Are you using proper flood use and technique? Use a heavily angled squeegee (~60° would be typical) stroke. The purpose is not to push ink through the screen but to leave a relatively heavy layer of ink in the mesh and on top of the mesh. A flooded screen will dry slower than an un-flooded screen. The screen should be flooded whenever the printing process has come to a stop. In between substrate changes, etc.
If you need a thinner, the RE180 is the thinner to use with 9700

 

[rustyhill]

thanks to all that replied to my post. It seems the final verdict related to my artwork being to close to the edge of my frame.
This was creating an inconsistent pressure while I was printing. I also had no ink well for my ink to sit before I started to flood. This caused the ink to basically fall back into my artwork and bled through to the other side of the screen. I resolved this by moving my artwork further back to the middle of the screen. I have ordered the extra components everyone mentioned and they have contributed to better outcomes for this project.

Thanks again!