S-mesh screen making issues

[jvanick]

And I'm also going to need to do more testing with exposure time and EOM and keep close track of my results... at the end i'll at the very least have a much better understanding of the finest details.
Now I just need to get myself an EOM gauge... any suggestions?

I use one of these:
http://www.ebay.com/itm/New-CEM-DT-156-Paint-Coating-Thickness-Gauge-Tester-F-NF-Probes-1250-Im-/221993822236?hash=item33afdce81c:g:a18AAOxy4dNSxTRB

for my emulsion testing, I use the following document:

https://docs.google.com/spreadsheets/d/1bsqE6POiBiCCztbQZlCZIOG_TlYNbZRtJ6_x7aTcShI/edit?usp=sharing

[Maff]

And I'm also going to need to do more testing with exposure time and EOM and keep close track of my results... at the end i'll at the very least have a much better understanding of the finest details.
Now I just need to get myself an EOM gauge... any suggestions?

I use one of these:
http://www.ebay.com/itm/New-CEM-DT-156-Paint-Coating-Thickness-Gauge-Tester-F-NF-Probes-1250-Im-/221993822236?hash=item33afdce81c:g:a18AAOxy4dNSxTRB

for my emulsion testing, I use the following document:

https://docs.google.com/spreadsheets/d/1bsqE6POiBiCCztbQZlCZIOG_TlYNbZRtJ6_x7aTcShI/edit?usp=sharing

Awesome Thanks!!

[JBLUE]

if you coat the T and S the same, S will have almost twice the thickness of the emulsion and you will have to increase your exposure times. Keep burning until there is no slime on the other side.

pierre

Right.  Usually we would coat 1x1 with the round side.  We have been trying 1x1 sharp side on 150s with slightly better results but still getting some slime. 
But we did also try increasing our exposure, in our initially test we doubled our exposure times and still getting some slime.

Maybe the screens weren't dry enough? we try to give them a good day of dry time after coat. 

Although we have our screens in a decently controlled environment I've noticed they are still affected by our weather... if it's super hot and humid in the summer we were fighting to keep the humidity down in the screen booth and also since it's been a lot colder we recently bumped up the heat... There was another topic recently discussing the colder weather and exposure times.

It all made me wonder if the s-mesh are just more sensitive... or am I just realizing that screen making in general needs to be more precise and conscious part of the process... everything with our Tmesh was easy... rarely any issues.

how long are your exposure times? I would expect a 3min +, possibly 5 with an 850W and 150S.

pierre

Thanks everyone,

Piere,  No we're much less.  With PHU we've been under a minute... but our T-mesh hits a solid 7 on the Stauffer strip every time. 
Could the layer of emulsion be that much thicker on a S-Mesh?  twice as much?   Like 150s vs 156t for example...

Also, what do you think about abrading s-mesh... anybody else doing that?

We use PHU and 150-S and on a 3K we are at 28 LTU or about 35 seconds. Screen is coated 1 on the shirt side and 2 on the squeegee side. EOM is way above 50% when we last checked. We land right around a 7 on the strip. Its a thick OEM but with a fast stroke and minimal off contact it deposits very little ink.

There is no need to abrade the mesh. We have have not had to abrade any of the S-Mesh that we use. We use 150-S, 180-S, 225-S, and 355-S with no issues at all.

[Colin]

The cracking/delaminating seems to be most prevalent in the upper lattitudes/colder regions.

Cold and dry....

At least that has been my feedback from other people and manufacturers.

[jvanick]

there might also be a correlation with low(er) off-contact.

we haven't calibrated the press in a while, we are running a bit over 3/16 of off-contact...

but you're right about the dry air.. I noticed these issues WAY worse starting in the fall.

however, the mesh abrasion definitely resolved the issue for us... with out it, you could actually HEAR the emulsion starting to crack...

[Shanarchy]

Cap question with S mesh:

I use Ulano EZ film. Which is a 50 micron film. It is recommended for mesh counts of 86-196.They also make a 30 micron recommended for mesh counts of 230-419. I am using 150/48, 180/48, and 225/40.

For the 150 and 180 should I still be using the 50 micron film like I used with standard mesh? I assumed yes because with cap film it's the same thickness regardless. But reading this has me wondering if I should be using the 30 micron film instead.

Thoughts?

[Underbase37]

Just a guick question, I  haven't seen it brought up yet.

Is your T-mesh white or yellow?
Is your S-mesh white or yellow?

Just asking bc this will change times as well.

I agree with Pierre, coating S-mesh the same as T-mesh will give you almost twice as much EOM on the S over the T.

I have not done any abrading on mesh in over ten years. We typically just put them into shorter runs for the first few uses, and this is efficient work hardening for our mesh, S or T.

Our S-mesh burns for twice as long as our T-mesh, but it is also white vs yellow.

Murphy

[Maff]

Just a guick question, I  haven't seen it brought up yet.

Is your T-mesh white or yellow?
Is your S-mesh white or yellow?

Just asking bc this will change times as well.

I agree with Pierre, coating S-mesh the same as T-mesh will give you almost twice as much EOM on the S over the T.

I have not done any abrading on mesh in over ten years. We typically just put them into shorter runs for the first few uses, and this is efficient work hardening for our mesh, S or T.

Our S-mesh burns for twice as long as our T-mesh, but it is also white vs yellow.

Murphy

White T-mesh: 110, 123, 156
Yellow T-mesh: 230, 280, 305

Yellow S-Mesh: 150s, 180s, 225s

All have been calculated separately and I have different settings for each mesh on the exposure unit.
Every once and while also through the stauffer strip on there to make sure things are consistent.

I definitely think that I need to pay closer attention to the EOM.  I just ordered an EOM gauge so I can start to find out precisely what that is per screen.

with the next batch of screens I get in I'm going to use direct prep 1 on just a couple and see if it makes any noticeable difference.

Once i get some new results I will check back in and post them.

thanks again for all of the advise!

[Frog]

with the next batch of screens I get in I'm going to use direct prep 1 on just a couple and see if it makes any noticeable difference.

We may still still need to figure out if all of that product's ingredients' effects are what changed your results, or just the detergent, the wetting agent, or the abrader

[jvanick]

with the next batch of screens I get in I'm going to use direct prep 1 on just a couple and see if it makes any noticeable difference.

We may still still need to figure out if all of that product's ingredients' effects are what changed your results, or just the detergent, the wetting agent, or the abrader

I was told that DirectPrep1 is just an abrader... DirectPrep2 is the wetting agent/detergent...

[Frog]

http://www.saati.com/images/chemicals/products/direct-prep-1.pdf

[jvanick]

http://www.saati.com/images/chemicals/products/direct-prep-1.pdf

Interesting. . They have me using the dp2 after the dp1.. it's only once during the screen process so it really doesn't bug me.

[Maff]

with the next batch of screens I get in I'm going to use direct prep 1 on just a couple and see if it makes any noticeable difference.

We may still still need to figure out if all of that product's ingredients' effects are what changed your results, or just the detergent, the wetting agent, or the abrader

True, that would skew the test results... But aren't most abraders also degreasers anyways?
Either way... I have already been using the Direct Prep-2 and haven't seen any significant changes in my situation.

[jvanick]

with the next batch of screens I get in I'm going to use direct prep 1 on just a couple and see if it makes any noticeable difference.

We may still still need to figure out if all of that product's ingredients' effects are what changed your results, or just the detergent, the wetting agent, or the abrader

True, that would skew the test results... But aren't most abraders also degreasers anyways?
Either way... I have already been using the Direct Prep-2 and haven't seen any significant changes in my situation.

Agreed... we had no difference with dp2 either... it was the dp1 that made things work for us.

[Frog]

True, that would skew the test results... But aren't most abraders also degreasers anyways?

The abrader I used back in the day before I learned better, was Ulano Microgrit 2, just a black powder, probably carborundum like a sharpening stone. They also sell it as a gel mixed with a degreaser, Unogel 23.

btw, years ago, I ground an old porthole into a telescope mirror, and used varying coarseness versions of similar grit to get the original rough shape.