Can someone explain to me how much emulsion I should apply?
I've ready just a thin coat on the shirt side is enough but also read one coat on the squeegee and shirt side and some say 2 or more on each. I'm just silkscreening line drawings on thin woven fabric with water based inks. Any advice?
Re: Can someone explain to me how much emulsion I should apply?
You need at least 1 and 1. Anyone who says one thin coat on one side of the screen is simply wrong. Beyond that, there's a lot of debate about 2 and 1, 2 and 2, 1 and 1, etc. The thickness of the emulsion is one of a few factors that will dictate how much ink you lay down. Given what you're printing, I don't imagine you want a lot of ink. 1 and 1 should be fine.
Screen makers don't really coat - we scrape. Mesh has holes in it, so maybe emulsion ends up on the other side! This is why you should coat with a rounded lip trough. You can prove this to yourself with a stepped coating that costs you a dollar in emulsion and you get measurable proof of what YOU are doing.
Start coating on the bottom of the screen until you see the emulsion link up on the other side, and form a shiny gloss coating.
If you don't fill the holes, when you turn the frame and make final coats from the inside of the screen, air will get trapped in the holes that are now bubbles, reducing the amount of emulsion in the holes as the water evaporates. That thin coating ends up looking like a waffle when it's dry.
Remember, emulsion can be as little 30% solids (70% water). When the water evaporates, the stencil shrinks and takes on the shape of the mesh. The shrinking usually means very little stencil on the bottom of the mesh, to make a gasket that will control the ink that makes your image.
__________________
How are you measuring? retired Ulano Technical Support Screen printing since 1979 - SGIA Academy Member
Last edited by RichardGreaves; March 14th, 2009 at 06:38 AM.
Re: Can someone explain to me how much emulsion I should apply?
Uh oh, I coated a few screens already with only one layer on the shirt side (but I did run it t least two times to try to achieve the even coat, does this count as a second coat). Anyways, the screens are dried, could I still apply another coat even that they're already dried?
Screen makers don't really coat - we scrape. Mesh has holes in it, so maybe emulsion ends up on the other side! This is why you should coat with a rounded lip trough. You can prove this to yourself with a stepped coating that costs you a dollar in emulsion and you get measurable proof of what YOU are doing.
Start coating on the bottom of the screen until you see the emulsion link up on the other side, and form a shiny gloss coating.
If you don't fill the holes, when you turn the frame and make final coats from the inside of the screen, air will get trapped in the holes that are now bubbles, reducing the amount of emulsion in the holes as the water evaporates. That thin coating ends up looking like a waffle when it's dry.
Remember, emulsion can be as little 30% solids (70% water). When the water evaporates, the stencil shrinks and takes on the shape of the mesh. The shrinking usually means very little stencil on the bottom of the mesh, to make a gasket that will control the ink that makes your image.
Thanks Richard for all your valuable info. Your products are the best and the easiest to find!
Re: Can someone explain to me how much emulsion I should apply?
Yes. Use the sharp lip of the trough. This is called a face coat.
Anything coated can have multiple coats - cars, fingernails or bathroom walls. What is unique about coating screens is that the the first coat has to fill the holes like a primer.
__________________
How are you measuring? retired Ulano Technical Support Screen printing since 1979 - SGIA Academy Member
Re: Can someone explain to me how much emulsion I should apply?
Quote:
Originally Posted by RichardGreaves
Yes. Use the sharp lip of the trough. This is called a face coat.
Anything coated can have multiple coats - cars, fingernails or bathroom walls. What is unique about coating screens is that the the first coat has to fill the holes like a primer.
Richard, thanks again! So a second coat even if the first coat is dried is fine. Can you explain to me why 1 coat won't be enough? I haven't yet used any screens with one coat but I'm just curious what would happen when I'm ready to squeegee
Can someone explain to me how much emulsion I should apply? 
