using a paint/coating thickness tester to check screen coating

[jvanick]

as I continue my quest to make better and more consistent screens:

I bought a new toy (DT-156 coating thickness tester) from ebay... (based on some of the other postings about using them).

anyways.. what's the proper technique to use to figure out EOM and emulsion coatings...

I assume I use it on an uncoated screen to figure out how many mils the mesh is, then use it after coating and drying to see how thick the coating is afterwards?

I also am assuming that I use one of the 'targets' that came with it on the other side of the screen?

Sorry for the dumb questions... just have never used something like this before and want to get the details...

[alan802]

You should have a small section on the screen without emulsion and you measure that first then the emulsion and that's your EOM.  Then you can figure the percentage EOMR to dial in everything even more than just knowing EOM thickness. On higher mesh counts you want to shoot for 10-15% EOMR and 20% is a good place to start on your other mesh counts.  We try for 25% on our lower mesh counts used for underbasing but it's totally up to the results you prefer in your shop.  Test your prints with varying stencil thicknesses.  Too thick and you're wasting emulsion, too thin and your print will not be crisp and clean on the edges. 

[jvanick]

ok, so I measured  300 and 200 counts screens.

is my math correct?  I'm kinda stupid when it comes to figuring out math problems like this.. LOL.. must have been hitting the bong too hard during algebra in high school.

on my 300 count: Mesh thickness 51um, Mesh+Emulsion 59um (59-51 = 8um  => 8/51 = 15.6% EOMR)

on my 200 count: Mesh thickness 80um, Mesh+Emulsion 87um (87-80 = 7um => 7/80 = 8.7% EOMR)

[blue moon]

ok, so I measured  300 and 200 counts screens.

is my math correct?  I'm kinda stupid when it comes to figuring out math problems like this.. LOL.. must have been hitting the bong too hard during algebra in high school.

on my 300 count: Mesh thickness 51um, Mesh+Emulsion 59um (59-51 = 8um  => 8/51 = 15.6% EOMR)

on my 200 count: Mesh thickness 80um, Mesh+Emulsion 87um (87-80 = 7um => 7/80 = 8.7% EOMR)

I have the same meter, here are few tips.
Hold in on the side when measuring (rubber strips).
calibrate the unit at 0 and 100. I think I was getting consistent results only with one of the two metal plates.
for the numbers, divide the larger with the smaller. For example, 59/51=1.157 so your EOM is 15.7%

here's some more info on it:
http://www.kiwo.com/Articles/Understanding%20Mesh%20Geometry.pdf

pierre

p.s. I can't seem to find my manual, any chance you could scan it and send it to me?