magnified emulsion picture request

[ericheartsu]

After posting about wanting to buy a loupe, we bought two, and now i'd like to play around and test them out!

first starting with our emulsion. Can anyone show me some images of what we should be looking for with our emulsion? Are there any images that you guys can share of what a good coat looks like, versus a bad one?

thanks!

[Frog]

The old article by Doug Grigar on our home page about "Coating for Maximum Effect" contains some close-ups of screens coated with and without good EOM, and its effect on stencil definition and sharp edges.

http://www.theshirtboard.com/index.php/topic,2621.0.html

[mimosatexas]

I just re-read that article, which is awesome btw, and was wondering if anyone else using S-mesh has had the same experience as me: 1/1 "round" (I use the monster max and it is kind of a middle ground between the standard sharp and round on other coaters) is all you need.  Now, I don't have a thickness gauge, so all I can do is test and look at things through a loupe, but I have started using 1/1 coats for everything but my 280T mesh which needs a 2/1 coat and the glisten happens on the first pass without fail every time with S-mesh (I use 135S, 150S, 180S, and 225S).

[ericheartsu]

We do 1/1 sharp (have to finish reading the article that frog posted later today), but looking through a loop, i feel like i'm getting undefined edges. I'll try and take a pic later today

[blue moon]

I just re-read that article, which is awesome btw, and was wondering if anyone else using S-mesh has had the same experience as me: 1/1 "round" (I use the monster max and it is kind of a middle ground between the standard sharp and round on other coaters) is all you need.  Now, I don't have a thickness gauge, so all I can do is test and look at things through a loupe, but I have started using 1/1 coats for everything but my 280T mesh which needs a 2/1 coat and the glisten happens on the first pass without fail every time with S-mesh (I use 135S, 150S, 180S, and 225S).

we coat 2/1 T mesh and 1/1 for S/LX mesh. It lets more through so you get the glisten on the first try.

pierre

[mimosatexas]

Awesome.  That is what I found and I think my stencils are sharp, but was curious if I might be undercoating compared to the norm.

[Frog]

It's pretty simple when you think about it.
The "glisten" indicates that the emulsion has penetrated through from the coating side. So, there is no hard and fast rule. Mesh thickness, mesh opening size, emulsion viscosity, coating speed and pressure, volume from sharp or round edge can all affect it. That's why it's such a handy visual guide for general purposes.

[ScreenPrinter123]

We are 1/1 round side on S-mesh as well

[alan802]

Coating tip:  If you're not able to get a glisten on S thread mesh counts under 225 with one stroke, then try coating slower.  Depending on your emulsion you should be able to reach "glisten" with one stroke.  Next time you coat, try going to the extreme on coating speed, where it takes 10-12 seconds to coat a 23x31 then take note of how those screens look compared to your normal coating methods.  When I coat, my speed is about 2-3"/sec and there is a noticeable difference between the screen I coat and my screen guy in terms of pinholes and other imperfections.  But that's not saying much since the last time I observed him coating he was doing one coat on the shirt side then two coats on the squeegee side when most of our screens can be done with a 1/1.

[blue moon]

Coating tip:  If you're not able to get a glisten on S thread mesh counts under 225 with one stroke, then try coating slower.  Depending on your emulsion you should be able to reach "glisten" with one stroke.  Next time you coat, try going to the extreme on coating speed, where it takes 10-12 seconds to coat a 23x31 then take note of how those screens look compared to your normal coating methods.  When I coat, my speed is about 2-3"/sec and there is a noticeable difference between the screen I coat and my screen guy in terms of pinholes and other imperfections.  But that's not saying much since the last time I observed him coating he was doing one coat on the shirt side then two coats on the squeegee side when most of our screens can be done with a 1/1.

we are at about 3 seconds per coat, too.

pierre

[ZooCity]

I agree with Alan.  Everyone that coats here is instructed to do a "10 Mississippi" count on each pass.  Nice and slow lets you fill in the mesh openings.  We do still get pinners sometimes but its from contamination, not lack of bridging.

Where this gets weird is that some similar rules to printing may apply- a faster coat with the right emulsion could potentially put down more eom just as a faster print stroke with the right ink pumps more ink through the mesh?

[ericheartsu]

I agree with Alan.  Everyone that coats here is instructed to do a "10 Mississippi" count on each pass.  Nice and slow lets you fill in the mesh openings.  We do still get pinners sometimes but its from contamination, not lack of bridging.

can you explain more on this subject? Also have you played around with the saati PHU yet?

[Colin]

The PHU has a higher viscocity than most emulsions I have used.  Meaning it is more like a long long bodied white ink.  It doesn't shear fast.  So you are forced to coat a little slower.  It has its own built in "10 Mississippi".

The reason to coat slow is so the emulsion has time to flow through the mesh openenings.

The Aquasol HV by contrast is like butter and you can coat lightning fast with it. 

[alan802]

Eric, next time you are coating screens (or whoever coats there) do it somewhere that you have plenty of light to see what's going on.  Coat a screen at 10"/sec then coat another at 2"/sec and just compare the screens after the first coat of the shirt side.  On the slow stroke screen coat the squeegee side with another slow stroke, it doesn't have to be as slow but make it about half of the speed as the other.  Then do your other screen with the same speed you did the shirt side. Then mark each one with a post-it note to tell which is which the next day so you can examine them after they've dried.  You don't have a thickness gauge but with your loupe and the naked eye you should be able to see an almost perfect screen versus an average screen. 

[alan802]

I'd imagine that you CTS guys would see pinholes about as often as Christmas rolls around if you coat your screen right.  That's one of the things I'm looking forward to a lot with CTS is not having to examine the screen for a minute looking for pinholes and other imperfections that come from poor reclaiming, poor coating technique, dirty film and dirty expo glass.