# How necessary is it to coat BOTH sides of the screen with emulsion?



## Megaman (Sep 15, 2010)

I was just wondering how necessary emulsion coating BOTH sides of the screen is. Ive heard from people and seen in videos that it is not a necessary step and uses more emulsion. What advice can you guys give me on this? do you condone this?


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## Solmu (Aug 15, 2005)

Both if you want it to bond properly. You might get away with coating one side some of the time, but you're taking unnecessary risks at that point.


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## chasamax (Jul 12, 2010)

I agree. I have heard of some people coating just the print side.. to me, that is a disaster in the making. Especially for long print runs (like more than one print


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## cubedecibel (Nov 1, 2009)

I coat only the outside. Works for me.


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## reximages (Apr 3, 2010)

I coat once on the putside and twice on the inside. I never have pinholes and like one person said ... you can print long runs with little to no headache. I use the rounder side of the scooper.


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## CNClark (Mar 2, 2010)

It can be done, however stencil thickness is an important aspect of screen printing, and often overlooked. If you break down the cost of emulsion to a per print price, what are you really gaining by not coating the ink side. Nothing! And you are putting additional wear on your blades, you are probably having to make two passes with the squeegee to get proper coverage of the ink due to lack of stencil thickness. I would suggest coating both sides, that will make the best stencil.


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## cubedecibel (Nov 1, 2009)

CNClark said:


> ..stencil thickness is an important aspect of screen printing.


I have never heard of that. Can you explain why that is important?

I'm definetly gonna try coating both sides, to see if there is a difference. Should I set the exposure time any different?

This is interesting. 

Edit: I'm using Azocol Z8, btw


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## CNClark (Mar 2, 2010)

The amount of ink you lay down is directly linked to the thickness of your stencil. Theoretically, however thick your stencil is, is how thick the ink deposit will be. Of course, there are other factors at play, tension, off-contact, and squeegee pressure. But assuming those variables are optimal, stencil thickness determines ink deposit.


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## CNClark (Mar 2, 2010)

And yes, you will need to reevaluate burn times, as they will increase when adding another coat. Process is 2 passes on substrate side, followed by one pass on squeegee side in my shop. Screens are stored substrate side down.


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## chasamax (Jul 12, 2010)

cubedecibel said:


> I have never heard of that. Can you explain why that is important?
> 
> I'm definetly gonna try coating both sides, to see if there is a difference. Should I set the exposure time any different?
> 
> ...


Stencil thickness is what dictates the amount of ink that goes on the shirt. Especially important when dealing with white ink on dark shirts.

I usually do 1/1, let it dry and then do another coating on the print side using the rounded edge of the scoop coater. Let that dry and it seems to do the trick for a better ink deposit.

I use Ulano QX-1 and QTX.


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## cubedecibel (Nov 1, 2009)

Hmm, but I'm using waterbased ink, that is not thick at all. Almost runny. I have no problems getting the garment, with one or two strokes.

I guess it's more important if you use plastisol?


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## chasamax (Jul 12, 2010)

Sorry. I was thinking 'Plastisol'. I haven't used waterbased so i surely couldn't answer that question.


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## Megaman (Sep 15, 2010)

i will be using water based as well...


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## Solmu (Aug 15, 2005)

It doesn't matter if you're using waterbased ink or plastisol. If you want to minimise pinholes, screen breakdown over the course of a print run, even inking of the print, hold fine detail on your screens, etc. etc. then coating both sides is better than just one. Most of these benefits are about the screen itself; it doesn't matter what ink you're using.

As Chris said above, the cost saving would be minimal anyway (it could even cost more in the long run if your screen breaks down during a print run without you noticing). Screen prep is one place not to cheapen out.


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## 73eyes (Jan 22, 2010)

Along with the "Cost savings is minimal" comments, if you're a small operation (and I mean small), its sometimes a rush to get all the emulsion used up before it starts to become difficult to rinse out. I take care of my emulsion, but at the same time, I figure its cheaper to buy it by the gallon and use it liberally than spend more on a quart size and be worried about running out.


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