Stanley called my name and I rose from my slumber....
I don't like to suggest any specific number of strokes with a coater because of the variables, but I do have reasons for my method.
1. The mesh has holes in it. We don't actually coat, we push emulsion into the holes. That zither like sound when you coat is the trough scraping the mesh. No frosting here! Emulsion ends up on the other side. That is why you you should start on the bottom and finish on the inside, so the emulsion ends up where it belongs - on the bottom.
2. Emulsion is mostly water that has to evaporate when it dries. If you have 38% solids, you have 62% water. When the water evaporates, the film takes on the shape of the mesh which can look like a waffle. For fluffy textiles, this doesn't matter much, but on non absorbent products like glass, metal or plastic you get edges that look like a saw. (Saw Tooth). Even if you fill the mesh openings completely, it will only have 38% solids when it is dry. This is like a tax from Mother Nature.
3. You should use a rounded lip coater (2mm). A sharp edge lip (.5 mm) will have a very hard time pushing emulsion into the holes to fill them. I have a page on the Ulano web site showing 6 strokes with a rounded and sharp edge trough. The sharp edge never forms a glossy coating on the inside of the mesh. Coating FAQ of Screen Making Products
4. A glossy inside proves you have completely filled the holes from the bottom of the screen. When you turn the screen around, there are no holes to trap air
(pinholes of the future), as you make your final coats from the inside to create stencil depth. How can you have pinholes if you have filled the holes with emulsion?
5. Emulsion on the inside of the screen is helpful to make a more durable stencil, (like a watch band), but, it's the stencil on the bottom that controls the image. Dry your screen so gravity can help pull the liquid to where it belongs. Emulsion doesn't know how it was coated on the mesh, but as a liquid, it does respond to gravity as it dries.
6. Too much final coating from the inside can cause drips. A thicker coating may be your target, but the mesh is what should be used to determine ink deposit, not the stencil - except when you are making a super thick stencil for special effects inks.
7. If you are keeping your emulsion cool by putting it in the refrigerator because it is the only place you can think of that is cooler than your coating room, at 42°F you are 10°F from ice cream. If you coat with cold emulsion, when it warms as it dries - it will drip.
8. A coating experiment costs nothing. Coat 3 times from the inside at different lengths like I show on the coating support page of the Ulano site and test the difference. Yes, a thicker more durable stencil will take longer to dry and longer to expose fully.
There are thousands of ways to coat. These are rules with reasons
to prevent something undesirable. You all know you can skip or shortcut these steps, and if it works, you win. If not, these would be the fundamentals.