slimy back. why???

[Fleetee]

Hey guys so I'm running some exposure test with the 21 step wedge. I'm playing with the cryocoat (I did 1:1 coatings) with 200 and 230 mesh counts.
Im getting 6-8s on the test but for some odd reason, the back/ink side of the screen consistently is slimy. the front is fine. why do you guys think this is?
I dried it over night and this time around I even dried it for over 12 hrs to ensure they would be dry. I even left a heater in the room for the first 1-2 hrs to help/ensure that it would be dried tmrw for these test.
but since im getting 6-8s on the test. it only makes sense that the back/ink side of the screens are slimy because they were not completely dried yet?

[screenxpress]

Are you saying 6-8s (seconds?) on exposure?

If not, I'm missing something.

I use cryocoat (1 - 2) and my exposure times on a 6 blacklight bulb Lumitron unit takes me 2 minutes and 30 seconds.

[Fleetee]

Are you saying 6-8s (seconds?) on exposure?

If not, I'm missing something.

I use cryocoat (1 - 2) and my exposure times on a 6 blacklight bulb Lumitron unit takes me 2 minutes and 30 seconds.

Oh I meant I was getting a 6-8 on the 21 wedge step test. Because the goal of the test is to get 7, so I included that information in because I was trying to state that I know I am exposing the screen around the right ball park.

And I think I found the answer to my slimy back... It's the light source from my exposure unit that is exposing the shirt side completely but not the ink side. Not a strong enough wattage of light

[RICK STEFANICK]

I would be coating with the sharp edge and medium pressure on the print side and then one on the squeegie side. Your life will get much easier with that emulsion. Your under exposing and I am JUST GUESSING that your coating too thick.

[Doug B]

  I agree with Rick. Definitely underexposed and probably too thick also.

[mooseman]

Take the time you got from wedge test and add about 25% to that time . Coat your screen the same as you did before and expose it. If the screen is still showing slime which is most likely under exposed emulsion you may be coating too thick.
You might also try adding 50% exposure time as another indicator.
You can actually do this all in one screen just the same as you did as you performed the wedge test. Expose a part of the screen at your calculated time, another section at time + 25% and a third section of the screen at +50%.
I might suggest you are not totally evaluating the step wedge test results you are getting.
Lastly if your screen comes out OK and you was it out but the edgges of the design, (the emulsion) lifts and curls or just wrinkles then you have way too much coating thickness.
Most important change only one element at a try otherwise if your results change you will not know what change was responsible for the result.
mooseman

[GKitson]

https://www.youtube.com/watch?v=5UPRYQY7P2M&t=6s

Cryocoat will require an aggressive washout

[Frog]

Slime is definitely an indication of insufficient exposure.
Many here have stated that they figure the coating is too thick. I am not too sure of this as I would have a hard time coating only 1/1 and having too thick of a coating without also having quite a mess. With the round side, I would find myself generally using two coats on the print side, and then one to finish on the inside.
Of course, for plastisol, I use the glisten method to help me almost automatically get the optimum EOM on any mesh count. And, of course, practice helps.
Our newbie friend would be well advised to read the article about this on the home page. http://www.theshirtboard.com/index.php/topic,2621.0.html. There is also an article about exposure.
In fact, any newbie would be well advised to read any article there. Old, but still holding much validity, and good background.
(Also, we may lose this page when the complete update takes place)
As has been mentioned by others, questions are fine, but newbies are all advised to read, read, read. Take advantage of the years of knowledge stored here.

[Fleetee]

Thanks guys. I coated a bunch of screens with diazo yesterday. I used the sharper edge this time and did a 1:2. I wish i waited til I read this, I would've done a 1:1 with the sharper edge seeing that everyone is stating my coat is too thick, but I thought the EOM would be too low if I did a 1:1 with the sharp edge. Maybe a 1:1 with the round edge would be perfect? I will also keep in mind to put less pressure to apply less emulsion moving forward. Let's see how it goes.
Thanks guys

[Fleetee]

Slime is definitely an indication of insufficient exposure.
Many here have stated that they figure the coating is too thick. I am not too sure of this as I would have a hard time coating only 1/1 and having too thick of a coating without also having quite a mess. With the round side, I would find myself generally using two coats on the print side, and then one to finish on the inside.
Of course, for plastisol, I use the glisten method to help me almost automatically get the optimum EOM on any mesh count. And, of course, practice helps.
Our newbie friend would be well advised to read the article about this on the home page. http://www.theshirtboard.com/index.php/topic,2621.0.html. There is also an article about exposure.
In fact, any newbie would be well advised to read any article there. Old, but still holding much validity, and good background.
(Also, we may lose this page when the complete update takes place)
As has been mentioned by others, questions are fine, but newbies are all advised to read, read, read. Take advantage of the years of knowledge stored here.

Yea but I was confused because I was getting a 6-7 on the test meaning the exposure time was correct but the back/ink side was still slimy. Thought it was because of my weak exposure unit not exposing all the way to the back/ink side of the screen.

[Frog]

Slime is definitely an indication of insufficient exposure.
Many here have stated that they figure the coating is too thick. I am not too sure of this as I would have a hard time coating only 1/1 and having too thick of a coating without also having quite a mess. With the round side, I would find myself generally using two coats on the print side, and then one to finish on the inside.
Of course, for plastisol, I use the glisten method to help me almost automatically get the optimum EOM on any mesh count. And, of course, practice helps.
Our newbie friend would be well advised to read the article about this on the home page. http://www.theshirtboard.com/index.php/topic,2621.0.html. There is also an article about exposure.
In fact, any newbie would be well advised to read any article there. Old, but still holding much validity, and good background.
(Also, we may lose this page when the complete update takes place)
As has been mentioned by others, questions are fine, but newbies are all advised to read, read, read. Take advantage of the years of knowledge stored here.

Yea but I was confused because I was getting a 6-7 on the test meaning the exposure time was correct but the back/ink side was still slimy. Thought it was because of my weak exposure unit not exposing all the way to the back/ink side of the screen.

Might well be. In fact, this was even a complaint many were having with newer LED's with certain emulsions as well.
Have you tried kicking up the time? Did it change the test strip result?

Thanks guys. I coated a bunch of screens with diazo yesterday. I used the sharper edge this time and did a 1:2. I wish i waited til I read this, I would've done a 1:1 with the sharper edge seeing that everyone is stating my coat is too thick, but I thought the EOM would be too low if I did a 1:1 with the sharp edge. Maybe a 1:1 with the round edge would be perfect? I will also keep in mind to put less pressure to apply less emulsion moving forward. Let's see how it goes.
Thanks guys

First off, remember that this glisten coating method is applicable only to plastisol ink. (Water base will be a whole new learning curve for you)
The glisten method provides a visual reference as to how much emulsion to use, and then, self-corrects. It even allows you to go back and re-do a problem stroke, as it is the final stroke on the squeegee side that actually takes this extra back. As Douglas states in the article "Regardless of the number of strokes on the substrate side, the amount of emulsion deposited is always controlled by the final strokes on the squeegee side pushing emulsion to the print side while metering the total emulsion by returning excess back into the coater."
Using the round edge merely speeds up the process.

[blue moon]

Slime is definitely an indication of insufficient exposure.
Many here have stated that they figure the coating is too thick. I am not too sure of this as I would have a hard time coating only 1/1 and having too thick of a coating without also having quite a mess. With the round side, I would find myself generally using two coats on the print side, and then one to finish on the inside.
Of course, for plastisol, I use the glisten method to help me almost automatically get the optimum EOM on any mesh count. And, of course, practice helps.
Our newbie friend would be well advised to read the article about this on the home page. http://www.theshirtboard.com/index.php/topic,2621.0.html. There is also an article about exposure.
In fact, any newbie would be well advised to read any article there. Old, but still holding much validity, and good background.
(Also, we may lose this page when the complete update takes place)
As has been mentioned by others, questions are fine, but newbies are all advised to read, read, read. Take advantage of the years of knowledge stored here.

Yea but I was confused because I was getting a 6-7 on the test meaning the exposure time was correct but the back/ink side was still slimy. Thought it was because of my weak exposure unit not exposing all the way to the back/ink side of the screen.

you mentioned 6-8 in the original post. solid 8 will require about double the exposure of a 6, so while the numbers are not that far apart, the results are.

Additionally, no all emulsions will expose properly at 7. If you get a solid 7 on every screen, that just means you are exposing them all the same (assuming your EOM, mesh and emulsion are the same). You might require a solid 8 based on what you are saying.

pierre

there is a lot more to this than can fit in a forum answer. Additionally, you are probably misinterpreting a lot that is being said. Get somebody who know's what's going on to help you on site. All you are doing right now is struggling to get below entry level results. It will take you another two years to get to the best practices at this pace. . .