# Scoop Coater



## Smacken3 (Mar 8, 2007)

I just ordered a scoop coater to coat my screens with emulsion. ( trough shaped device) Was wondering if anyone uses one or has used one and if you like using it. What are the pros and cons of it?


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## Locklear (Nov 24, 2006)

I recently started using one as well. So far so good...just takes a little bit of practice to get the right consistency of emulsion on the screen.

I did have some problems getting too much emulsion at the bottoms and sides, but after a few tries, I got a lot better. 

It's definitely the best way to get a smooth, even coat of emulsion.


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## Smacken3 (Mar 8, 2007)

Locklear said:


> I recently started using one as well. So far so good...just takes a little bit of practice to get the right consistency of emulsion on the screen.
> 
> I did have some problems getting too much emulsion at the bottoms and sides, but after a few tries, I got a lot better.
> 
> It's definitely the best way to get a smooth, even coat of emulsion.


How exactly do you use it? What are some good techniques you have discovered to spread the emulsion precisely? Do you do it on just one side of the screen and then use a squeegee on the other?


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## Fluid (Jun 20, 2005)

http://screenprinters.net/articles/index.php?art=38
heres some info that might help.


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## RichardGreaves (Nov 7, 2006)

*Re: Scoop Coater is a registered trade mark for an emulsion coater*



Smacken3 said:


> How exactly do you use it?


I want you to use an emulsion trough with a rounded (2mm) thick edge and a thin edge.

Use the rounded edge for initial coats. Keep the coater filled with emulsion so there is some liquid pressure and you don't have to wait as tip the coater against the screen and start to coat.

Remember, the emulsion ends up on the other side of the mesh that you are coating.

Tip the coater against the mesh until the liquid touches all the way across the edge.

With a slow, even stroke, coat the mesh. Slow and stop before you get to the top and roll you hands back, then scrape the last little bit, back into the coater.








No one can tell you how many times to coat.
No one can tell you how many times to coat.

You have to check to see if you have pushed enough emulsion through the mesh for it to link up on the other side and make a *smooth, glass like finish* on the squeegee side of the screen.









Now turn the screen around and make a final coat on the squeegee side of the mesh and it will push all the emulsion through the mesh to the stencil side where all the work will be done.

Emulsion is mostly water that must evaporate befor you can expost the screen. As the water leaves the film it shrinks and takes on the rough shape of the mesh.

If you want a smooth gasket to control the ink, you should add a face coat to the stencil side (it doesn't help to add more emulsion to the squeegee side) with the SHARP end of the squeegee.

While you are at it, try an experiment. Coat a screen with the rounded edge until it is glossy in the inside. Take another screen of the same mesh and coat with the sharp edge until it matches the round edge. 

You will find it take many many more coats to equal the round edge.


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## Smacken3 (Mar 8, 2007)

wow excellent! I ordered a 15" scoop coater for my 19"x22" screens. Will that work well?


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## RichardGreaves (Nov 7, 2006)

Smacken3 said:


> wow excellent! I ordered a 15" scoop coater for my 19"x22" screens. Will that work well?


No. 
19" wide frame. 
Minus 1.5 to 1.6 inches for the frame bars x 2 bars = 3"
19" minus 3" = 16" frame ID

Filled with a 15" coater, that only leave .5" on either side.
=========
Now .....

Mesh tension resistance to pressure - either the squeegee or coater.

Whatever force it take to deflect the center of the screen a certain distance, it takes 10 TIMES that amount of force to get the same deflection 1 inch from the inside of the frame.

You will push on the mesh with the coater but you will probably get a skid mark of thicker emulsion down the middle of your screen.

I would suggest 2" of free area on either side which would be a 12" coater.

Now you will tell me that your image is 12", so you have to compromise.

Think about turning your screen on it's side and you will have loads of free mesh!

Then you will tell me your image is 14" long.


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## Solmu (Aug 15, 2005)

Smacken3 said:


> Was wondering if anyone uses one or has used one and if you like using it.


I'd say very very few printers *don't* use one. Some people use a squeegee or a piece of cardboard, some people use a coating machine... while I could be wrong I imagine the vast majority of people use a scoop coater. I wouldn't say I _like_ using it... it's just a necessity. I don't _not_ like it either though. They're relatively easy to use, they get the job done... there's not much to it really.

Great advice from Richard on the how-to. While I agree that "_No one can tell you how many times to coat._", the rule of thumb is one on each side.

I've been known to do half a dozen passes (some to add emulsion, some to remove it) if I made a mistake that needed correcting though.


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## Smacken3 (Mar 8, 2007)

great! so basically scoop coaters are the way to go. I have been using a squeegee to coat my screens and for some reason the screens have not been coming out all that well. Not too bad, but not too good either.


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## feilong (Jan 23, 2007)

I use Capilary Film for Emulsion, way more uniform and eay to use.


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## amp267 (Oct 11, 2006)

dont forget to turn your screen 180 for every coat you apply.


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## Smacken3 (Mar 8, 2007)

amp267 said:


> dont forget to turn your screen 180 for every coat you apply.


 180? front to back or upside down?


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## Greg Hamrick (Jan 25, 2007)

Coat from the bottom to top, then turn it upside down and coat up to the top in that direction. A lot of the time, you can get away with coating the shirt side one way, then turn it upset down and coat the squeegee side in the other direction.

.


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## RichardGreaves (Nov 7, 2006)

Greg Hamrick said:


> Coat from the bottom to top, then turn it upside down and coat up to the top in that direction. A lot of the time, you can get away with coating the shirt side one way, then turn it upset down and coat the squeegee side in the other direction.


I question the logic of turning the screen 180 degrees. How does the liquid emulsion know which direction it was coated at?

As it dries, squeegee side up, gravity will draw the liquid emulsion to the stencil side of the mesh and hold it there with surface tension. This is also why if you put too many coats on the mesh, it will drip.


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## amp267 (Oct 11, 2006)

ok this is probably going to confuse some people including me. im no expert just a home based printer. but i guess my theory would be as you coat it one way up, you are coating the bottom of the mesh strands. as the scoop moves in an upward movement its hitting along the bottom of the mesh strands only. i know some are going to say its liquid and it fills in the gaps. but i seem to get a better coat when i flip it 180. if you look at the opposite side of your first coat that you applied to the print side of course, you will notice tiny dots where the emulsion just has not passed through. i have noticed the dots even after to coats without turning it 180. but when i do turn it 180 its alot more of a uniform coat. i guess the best way i can discribe it is, imagine running your fingers across a row of bars on a fence. your fingers are only touching one side of the bar. you cant touch the opposite side because you are only moving in one direction foward. now if you stop turn around and walk the opposite way your fingers(emulsion) has now touched(coated) both sides of the bars(mesh strands). please let me know if this makes any sense.


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## RichardGreaves (Nov 7, 2006)

I have never experianced the tiny dots you describe. As I described in Post #5 above, I use a rounded edge coater and coat until there is a smooth glass-like film on the inside of the screen where the emlulsion has linked up on the other side of the mesh. This shows me I have no open areas of bubbles in the mesh openings.


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## Greg Hamrick (Jan 25, 2007)

amp267 said:


> ok this is probably going to confuse some people including me. im no expert just a home based printer. but i guess my theory would be as you coat it one way up, you are coating the bottom of the mesh strands. as the scoop moves in an upward movement its hitting along the bottom of the mesh strands only. i know some are going to say its liquid and it fills in the gaps. but i seem to get a better coat when i flip it 180. if you look at the opposite side of your first coat that you applied to the print side of course, you will notice tiny dots where the emulsion just has not passed through. i have noticed the dots even after to coats without turning it 180. but when i do turn it 180 its alot more of a uniform coat. i guess the best way i can discribe it is, imagine running your fingers across a row of bars on a fence. your fingers are only touching one side of the bar. you cant touch the opposite side because you are only moving in one direction foward. now if you stop turn around and walk the opposite way your fingers(emulsion) has now touched(coated) both sides of the bars(mesh strands). please let me know if this makes any sense.


That is a very good "simple way to put it." Greaves just has a more technical way of putting things. I think he writes for a screen rag? What do you say Richard...are you a writer?

.


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