emulsion breakdown under squeegee

[downtowntshirts]

hey guys,
  im new to this board. took me a while to get off that other board. anyway, been printing automatically for about five years. like to think im pretty good at it but i have a problem. my emulsion breaks down and i get dots under the spot where the squeegee stops at the end of the print stroke. i think that i am processing screens well. we scrub with ink degrader, take the emulsion out with emulsion remover and then degrease and dehaze and then rinse very well. we then coat 2 strokes on each side. and we use chromablue emulsion. any tips on stopping this breakdown and also pinholes.
thanks,
tom

[Frog]

I am certainly not the go-to guy on automatic problems, but perhaps your problem is something as simple as too much pressure on either the flood or print stroke.
Pinholes are almost always due to dust, and can be helped with better hygiene.

And, we're glad that you found your way here.

[mk162]

the adhesive on the platen is pulling the emulsion off the screen.

[JBLUE]

Run a piece of tape where the squeegee starts and stops. Is it happening on long or short runs? Either way tape both the start and stopping points and you wont ever have that issue.

[tonypep]

Make sure you coat your screens smoothly and slowly. Quick coats will cause bubbles that can pop later in the run. Be sure the squeegee rubber is rounded at the corners. Somethings wrong if you are de-hazing each time. Most people use an ink remover than combo reclaim-dehaze product. Two step process.

[Fluid]

Sounds like your stencils are too thin coupled with your squeegee pressure being too much yet the main culprit is most likely too thin of a stencil.

Tape obviously will work yet is only masking the problem.  Try looking into your coating process and see if the issue lies there.

[Prosperi-Tees]

I notice he said degrease before dehazing, shouldn't that be reversed. And yes only dehaze if absolutely needed but Easiway 701 is a great combo product.

[sportsshoppe]

Run a piece of tape where the squeegee starts and stops. Is it happening on long or short runs? Either way tape both the start and stopping points and you wont ever have that issue.

Exactly what I do.... But I have a V squeegee but I am sure it works for the others also.

[Screened Gear]

Have you checked your screen Moisture levels? I am just guessing because of the change in the season. A well made screen sould never break down.

[Fluid]

Have you checked your screen Moisture levels? I am just guessing because of the change in the season. A well made screen sould never break down.

agree 100% Something is happening in the screen prep. I don't think degreasing before dehazing is what is causing this issue.  Can play with the entire screen falling apart yet not like what is being described

[ZooCity]

Make sure you coat your screens smoothly and slowly. Quick coats will cause bubbles that can pop later in the run. Be sure the squeegee rubber is rounded at the corners.

^^^^ Take this advice above and you'll likely solve the issue.^^^^

This also means you are probably printing with sharp blades which is a good thin.  We're manual printers, I've had this issue on longer runs and I'm fairly confident our screens are properly prepped, coated, fully exposed.  The fact that you are seeing this issue only on the corners of the blade and not across the length of it's edge indicates you just need to round off those corners in my opinion as your screen is capable of withstanding the squeegee passes, just not the increased gouging that happens on the corners. 

Purely technically speaking, this shouldn't be an issue if you had absolutely perfect blade contact to the stencil but nobody does or really needs to if the setup is making good prints so round them corners.

Somethings wrong if you are de-hazing each time. Most people use an ink remover than combo reclaim-dehaze product. Two step process.

If you mean the caustic dehazers then yes, something would be very wrong.  The gentler types such as Franmar's D-haze are meant to be used as part of each reclamation cycle and we use it on every screen, every time.  When rinsed it does create it's own degreaser but I don't like to pull a screen out of the booth right after dehazing and put it to dry in the hot box, they always have issues from the lingering dehazer mist or something.  So, we degrease as a final step after thoroughly rinsing the booth and ventilating.  Murkami recommends a dedicated ink removal/degrading station, a seperate washout booth for degreasing and resolving screens only and another for reclaim and I couldn't agree more but that ain't going to happen around here for a minute unless santa brings us a second, large washout booth.

I believe liquid renuit is meant to be used in a similar manner as the D-haze?

[Gabe]

I had that issue before
one thing i would try is to after you burned your image in the screen
to rinse the image with a high pressured water in one corner of the screen if it peels to easy
you need to increase your exposure time

[Frog]

Somethings wrong if you are de-hazing each time. Most people use an ink remover than combo reclaim-dehaze product. Two step process.

If you mean the caustic dehazers then yes, something would be very wrong.  The gentler types such as Franmar's D-haze are meant to be used as part of each reclamation cycle and we use it on every screen, every time.  When rinsed it does create it's own degreaser but I don't like to pull a screen out of the booth right after dehazing and put it to dry in the hot box, they always have issues from the lingering dehazer mist or something.  So, we degrease as a final step after thoroughly rinsing the booth and ventilating.  Murkami recommends a dedicated ink removal/degrading station, a seperate washout booth for degreasing and resolving screens only and another for reclaim and I couldn't agree more but that ain't going to happen around here for a minute unless santa brings us a second, large washout booth.

I believe liquid renuit is meant to be used in a similar manner as the D-haze?

Liquid Renuit is probably gentle enough to use each time, but often an unnecessary step and/or expense (though it does also cover the degrease step as well).