Capillary film such as Ulano ez film is the most popular as you will not have to wait until the screen dries. With liquid emulsions, you must wait until the screen is dry which can make your work take longer which is not desirable especially if you are working on a large project.
The thickness of the stencil is according to the mesh count. The larger the mesh count the thicker the stencil. The capillary film will be pulled into the mesh while the film takes in the water from the mesh. You should use a thick film if you are working with coarse mesh or the stencil will not be as durable.
When you purchase new mesh from the manufacturer it will usually have oil residue from the manufacturing process that will need to be removed. The same goes for the screens you use as you will need to remove the residue of the product used to break down the stencil. In order to clean the screens, you will need a degreaser. Never use any type of household cleaners but purchase a degreaser designed for screens. While using the degreaser, look for foam. Once you see the foam, you will know that part of the screen is clean.
The coating area needs to be thoroughly cleaned and you will need ultra violet safe lights. Under normal lighting, the stencil may be pre-exposed which will not allow it to washout. Companies that manufacture emulsion suggest yellow or gold fluorescent lamps, but remember that photo-polymer can be damaged with yellow lighting so ensure the coating, as well as the drying room, are dark.
Applying the capillary film can be done in a sink. The sink should not be in the drying area where you keep the screens. The best design for the sink is one that has a holder for the screen in the bottom and is back lit. When you move the stencil from the sink to the drying area, remember that any light can expose the film, so be careful.
Applying is easy, but you do need to have all of the equipment at hand so the capillary film will roll on the mesh easily similar to hitting a golf ball. Your capillary film should be beside the sink and you should use a squeegee and always have dry rags close by.
You just want to barely get the film wet just so it will stick to the mesh. You can wet the film and mesh together so the water will be absorbed and the film will soften and stick to the mesh.
It is suggested to pour the water on the mesh instead of using a spray as the water can go through the mesh. You should read the instructions on the capillary film to know how much water is recommended for the thickness of the film.
You can easily determine the amount of water to use. As you pour the water over the mesh, there will be a ripple effect. Once the rippling stops, the mesh is holding all the water it can absorb. You only have a few seconds after this to place the film around the time you can count to ten. When you get to ten, place your film on the screen and then pour water again.