[DreSilva]

HI,

New to screen printing here. After several attempts at burning a screen, i thought i got close with two OK looking screens but after running white plastisol ink on the meshes i am getting weird edges showing up on the screen. Was wondering if some one could point out the problem I'm having or a direction to look into to solve the issue im having. I know its all trial and error but just getting to the point of burning a good screen to print has been a bit frustrating.

I'm using #110 screens, Ulano Orange, exposure unit Vastex E-100 with Stouffer 21-step calc and Ecotex White plastisol.

Exposure times was 42 sec for one screen and 29 sec for the second screen but both screen have the same edge issue.

Currently those screen where only coated on the print side only (heard Ulano could be used with one coat). I currently have 1:1 screens drying.

This is all new to me so even setting the press

up may be part of it. Using the Quarter method for Off contact.

I've attached a few picture to show the issue I'm having. I would really appreciate any info or advice tremendously.

Thanks
Andre

Edit: sorry forgot to say, that im using old T-shirt material to print on, in the process of getting new material to test print on. Also it seems i get a bumpy print and sometimes streaking?

 

[TABOB]

Too much pressure for the ink and mesh combination.
Lower the off-contact to 1/32 inch (half the thickness of a quarter), and use a smaller squeegee.
This way you will be able to print with less pressure.
Try this and report back.

 

[DreSilva]

Too much pressure for the ink and mesh combination.
Lower the off-contact to 1/32 inch (half the thickness of a quarter), and use a smaller squeegee.
This way you will be able to print with less pressure.
Try this and report back.

Thanks Bob, will do.

 

[Rockers]

This looks almost like your emulsion is delaminating the mesh around the edges of the image. Are you degreasing your screens? Not that you need to if you have a proper power washer but many shops use a cheap one from the home center that just won`t do the job.
Recommended exposure time for Ulano Orange is 1 Minute for a 305 mesh, you are on a 110 and you are not even exposing the screen for the minimum time recommended for a much higher mesh count. I would increase exposure time see if you get the same issue around your edges. You have read the technical datasheet for Ulano Orange, right? https://static1.squarespace.com/sta...707f4df1/1531244808661/ulanoorangetds2012.pdf

 

[TABOB]

This looks almost like your emulsion is delaminating the mesh around the edges of the image.

It isn't and it wouldn't matter anyway.

Not that you need to if you have a proper power washer but many shops use a cheap one from the home center that just won`t do the job.

For the designs shown above regular water pressure is more than enough.
Too much water pressure will destroy the screen and is not a substitute to de-greasing.
Cheap power washers do an excellent job for halftones and for reclaiming screens. The problem is that they don't last.

 

[Rockers]

It isn't and it wouldn't matter anyway.


For the designs shown above regular water pressure is more than enough.
Too much water pressure will destroy the screen and is not a substitute to de-greasing.
Cheap power washers do an excellent job for halftones and for reclaiming screens. The problem is that they don't last.

Oh I might have incorrectly given you the impression we develop with extremely high pressure, no way... we would blow the image right off. We have two pressure washers, a consumer one and a professional range washer. All screens are developed with lower pressure. But like I said we have not used degreaser in over 8 years. The higher pressure will take care of it. There are plenty of shops out there, especially in the States that have made degreasing a thing of the past. But of course, what works in my shop might not work in your shop. And yes the cheap washers need replacing every few month.

 

[Rockers]

I just noticed this now, but your stencil is sitting on the squeegee side of your screen, anything but ideal. I`m pretty certain you would not have these issues if you would coat your screen 1/1 with the last coat on the squeegee side of the screen pushing the emulsion to the substrate side of the screen. When you flood the screen there is no stencil on the substrate side of the screen for the ink can sit in or in this case hang in. Well I guess or hope you know what I mean.

 

[TABOB]

I just noticed this now, but your stencil is sitting on the squeegee side of your screen, anything but ideal.

It's actually the opposite... The stencil is on the print side.
This is perfectly OK for small runs, and helpful when printing with a push stroke... The squeegee does not stick.

 

[Rockers]

It's actually the opposite... The stencil is on the print side.
This is perfectly OK for small runs, and helpful when printing with a push stroke... The squeegee does not stick.

So you are saying in the top photo the stencil is on the print side? Print side = substrate side, the side facing the garment? Sorry we might just be talking past each other as English is not my first language.

 

[TABOB]

So you are saying in the top photo the stencil is on the print side? Print side = substrate side, the side facing the garment?

Currently those screen where only coated on the print side only

That's what the OP wrote in the first post, and it is also obvious in the first photo.
This is similar to using capillary film, and there is nothing wrong with it.

 

[Rockers]

That's what the OP wrote in the first post, and it is also obvious in the first photo.
This is similar to using capillary film, and there is nothing wrong with it.

Yes I totally agree, if the stencil would be on the print side of the screen similar to capillary film. As a matter of fact one would assume the stencil, regardless how it was made ( capillary film or liquid emulsion) should always be on the print side of the screen. But as we can see in his first photo the stencil is on the squeegee side of the screen, unless he always puts his ink on the print side of the screen
Now what he said was he coated the screen on the print side (only one coat) and no coat on the squeegee side. The result of this is in most cases that the emulsion is pushed through the mesh to the squeegee side of the screen. That`s why normally a second coat from the squeegee side is required to push the emulsion back through the mesh towards the print side, and then gravity will do the rest during the drying process if the screen was placed mesh down in the screen drying cabinet.

 

[DreSilva]

Hi guys,
Thank you for the responses. a lot of info LOL

I have been out of town so i haven't been able to do a lot of testing but i am starting back up this week. The short exposure times i had i was getting from the the 21 step calculator, i am going to try to do more exposure runs at the higher exposure times. BUT at the low times, visually the screen looks good after the exposure, but that's just visually to my eyes which isn't really saying much as i am a newb, i had done a few print test where i adjusted my Off Contact and that did stop the weird edges like on the third photo, but I'm using a pretty old press and the micro adjustments are really difficult to use. Again on 110 meshes. I still can't get good coverage pass of white on the substrate? even after warming and stirring the plastisol and flooding the mesh first. I think i do get a better pass when i do a push with the squeegee but still difficult to do a complete pass on the substrate. The next test exposures i will be using 205 and 305 meshes that i have plus i have new jersey knitted fabric to print on.

I will be trying your suggestions and i really appreciate the help. I'll post more pics as soon as i can.

Thanks