- Kieth Stevens
Scoop coaters, a tool used to coat screens with emulsion, usually don’t get a lot of “coverage” – pardon the pun. So here is Kieth Stevens with more information on scoop coaters:
“As mentioned, scoop coaters are used to coat printing screens with emulsion. A good scoop coater is an important tool and as mentioned in my previous blog (posted September 17, 2009) on how important good emulsion coverage is, here are some basic things to consider when choosing a scoop coater:
- Did you know that most emulsion scoop coaters have 2 sides that can be used? Take a look at your scoop coater and there should be a sharp edge on one side and a rounder, more blunt edge on the other.
The best way I can describe the reason for the two sides is to think of the edges as if the scoop coater were a squeegee.
Just as a hard sharp squeegee passes less ink, so does the sharp edge of the coater, whereas using the rounder edge will apply more emulsion using the same amount of passes.
- How many passes are needed to coat the screen? Usually 2 and 2 – that means, two coats of emulsion on the substrate (shirt or fabric) side and 2 coats on the ink side of the screen.
Let me give some practical examples of some scenarios: If you are coating a 110 mesh screen with a 2 and 2 coating technique using the round edge side of the scoop coater, you may find that this technique applies too much emulsion and the emulsion may begin to drip or run while it is drying. In this case it would be prudent to coat the screen using the sharper edge.
Similarly, if using the sharper edge on a 305 mesh with a 2 and 2 coating technique (depending on the viscosity of the emulsion you are using) you may find that this technique may not apply enough emulsion.
So here is my general “rule of thumb” on scoop coating techniques: On 160-count meshes and below, use the sharper edge and for mesh-counts above 160, use the rounder edge. Again, this is only a general guideline as each brand of scoop coater and emulsion is different. Some may find that with their particular emulsion, the rounder edge can be used above or below the 160-count mesh mark. The only way to know exactly is to test the technique using your tools and emulsion.
Be sure to protect the edges of your coater as any scratches or dents will affect the smoothness of the coating. If the edge does get a dent or a ding, use fine-grade sandpaper or other tool to repair it. If need be, go ahead and order a new one as scoop coaters are fairly inexpensive.
Just keep in mind that the edges of the scoop coater are tools which, if used correctly, can improve the quality of the prints and subsequently, improve the company’s profits.
For more info, please call your emulsion representative or look for their website. Usually their site lists some good information.
Have a great day."
Kieth Stevens
