Coating screens Rotate or flip?

[jsheridan]

I used to do 2/1 like you (shirt/squeegee), but with SP1400 and thin thread mesh 1/1 is perfect for basically everything.  I am in the process of testing out a bunch of variations though because I just had a handful of screens stretched with 83/71 mesh and the whole idea of those screens is one hit whites and shimmers etc.  Basically I am trying to get big eom with the same emulsion I like for everything else.  We'll see how that goes...

Actually the 83/71 was made for High Density ink as it can hold high tension with large openings for a super thick ink with a 500 micron capillary film.

[mimosatexas]

The whole idea FOR ME*

Haven't been happy with just having the 135 S statics, and I am all statics here, so I had some statics stretched with this mesh since I know it will clear with basically no pressure.  If the SP1400 isn't up to the task though when it comes to eom, I will likely look at other emulsions or cap film.

[Sbrem]

I used to do 2/1 like you (shirt/squeegee), but with SP1400 and thin thread mesh 1/1 is perfect for basically everything.  I am in the process of testing out a bunch of variations though because I just had a handful of screens stretched with 83/71 mesh and the whole idea of those screens is one hit whites and shimmers etc.  Basically I am trying to get big eom with the same emulsion I like for everything else.  We'll see how that goes...

you need to try 81SDE (saati sell it) It's an 81 thin thread...

Steve

[mimosatexas]

This is thin thread mesh and the specs are close to the 81/70 from Saati and 80/71 from murakami.  I didn't ask what brand it was honestly, but clearing it is MUCH easier than the standard 80/100 mesh I already had in stock.

[farmboygraphics]

https://youtu.be/6rDdq1BK88s
This is how I do it. Works for me.

[Rockers]

one of our fellow board members posted a very cool stand he built a few months ago, maybe someone (Andy?) can post the link... lots of pics too

Steve

http://www.theshirtboard.com/index.php/topic,14449.msg139646.html#msg139646

[Maff]

We just rotate, no flip. Been doing it that way for 10 years. It always has worked fine for us. Usually 2/1 shirt/squeegee side.
I always thought that if the automated coaters don't flip, than its probably not necessary. I just figure they probably spent a good deal of time and money researching the best way to coat.

[Frog]

We just rotate, no flip. Been doing it that way for 10 years. It always has worked fine for us. Usually 2/1 shirt/squeegee side.
I always thought that if the automated coaters don't flip, than its probably not necessary. I just figure they probably spent a good deal of time and money researching the best way to coat.

That's just it. The reason for flipping for the second coat is to compensate for the inconsistency of us humans, and the tendency to leave a slightly thicker deposit at the beginning of the stroke. It has been pointed out however, by someone far more knowledgeable than me, that in textile work, the difference is probably negligible.

[Sbrem]

This is thin thread mesh and the specs are close to the 81/70 from Saati and 80/71 from murakami.  I didn't ask what brand it was honestly, but clearing it is MUCH easier than the standard 80/100 mesh I already had in stock.

the 81SDE I spoke of is also a 70 thread, it's just so easy to get ink through, and the thin thread allows for more detail than the thicker threads...

Steve

[jsheridan]

It has been pointed out however, by someone far more knowledgeable than me, that in textile work, the difference is probably negligible.

+1

Our side of the screen printing realm is so low detail compared to electronic circuit and solar panel style printing that you can slob emulsion all over a screen with a nappy paint roller and still be able to expose and print it.

[alan802]

As far as the tools I have to measure stencils with, there is no difference between a screen that was coated, flipped, then coated again versus coated, spin around, coat.  Perhaps there is another way to measure or a tool that could show us a difference but I don't have it.  I've also measured hundreds of screens that were coated with the scoop coater full, half full, and virtually empty and there is never any measurable difference in those screens.  I had a screen guy that was filling up the scoop coater after every screen and of course when I told him it didn't matter and he was wasting SRI's time he didn't think I knew what I was talking about.  We did the test together and since that day he's been much more willing to listen to what I have to say about things.

I've done similar testing with coating speed and I've tried my best to test with different coating pressures but that was very difficult to do manually.  There is a noticeable difference between screens coated at 5-6"/sec and 15"/sec but there was no difference between 10"/sec and 15"/sec.  I saw more pinholes the faster we coated but that's to be expected.  It's fairly hard to coat much faster than 15/sec and honestly doing this type of testing manually isn't easy and therefore I'm not sure how accurate my results are.  I'd also like to do this test with an automatic scoop coater.

[Itsa Little CrOoked]

I too, have gone back to spinning. I was sold on flipping for several years because I thought I got fewer pinholes. 

Not so....

I hope I didn't mislead too many people into wasting all that time and effort, because I posted it on some forums. (Embarrassed....) It isn't worth the trouble.

I do 2 over 2 with the sharp edge of an AWT, but not the one Tom showed in his video above. I have that one too, I just don't care for the smaller capacity.