Though
it may not be rocket science, prepping a screen for screen printing
involves a few different variables. You must make special considerations
for factors like mesh count,
diameter and more if you want your printing efforts to yield acceptable
results. Following are five considerations that are very important to
effectively prep a screen that will enable maximum results when you’re
printing.
1. Select the proper mesh count: The proper mesh count will help to determine the amount of ink that
is deposited on the substrate onto which you are printing. Choose low
mesh counts for special-effects inks such as glitter (25-40 mesh),
reflective or puff type inks (110-125 mesh). Choose high mesh counts
(200-305) for more detailed or soft-hand prints.
2. Select the desired mesh thread diameter: A
thinner thread diameter for any given mesh count will reduce the
overall fabric thickness of the mesh and allow more ink to be deposited
onto the substrate due to lower flow resistance and larger open area.
The thinner thread diameter results in larger mesh openings and, thus,
makes printing easier. This becomes important when a clean, crisp image
or detailed design is desired, as the thinner tread diameter provides a
smoother surface to which the stencils can adhere.
3. Make sure your screen frames are clean, straight and level: Properly
cleaned and leveled frames will help ensure that the printed image
comes out crisp and clear. Personally, I prefer metal frames to wood,
since metal frames last longer, resist warping and splintering and tend
to hold the mesh tension longer. In addition, I also prefer retensional frames, since the mesh tension can easily be tightened or adjusted.
4. Tension the mesh properly: Follow
the manufacturer’s instructions for the ideal tension recommended for
the specific mesh being used. Make sure the tension is equal in both
warp (lengthwise) and weft (crossways) to achieve uniform mesh openings.
Once the ideal tension is achieved (measured in Newtons with a tension meter),
tension the mesh in the frame, let it sit and then retension again if
needed. Mesh often will stretch a little after the first tensioning
hence the fact that letting it relax and then recalibrating the tension
will more accurately achieve the ideal tension desired.
5. De-haze and degrease both sides of the mesh: De-hazing
removes ghost images of previous designs, ink stains and other
impurities that may have accumulated on reused mesh. Although it may not
be necessary to de-haze each time a screen is reclaimed, depending on
how much detail the next design requires, it is a good idea to de-haze
periodically, perhaps after two or three jobs.
Degreasing is
an important step before applying emulsion to the screen to remove
oils, dust, fingerprints, and other grime that may have settled on the
mesh. This step can improve the adhesion of the emulsion and prevent
pinholes and other imperfections, which may show up if the emulsion is
applied over dirty mesh. I recommend degreasing as a mandatory step in
prepping the screen prior to applying emulsion. After degreasing keep
frames in a dust-free environment until they are ready to be coated.
One last tip: Always
consider the manufacturer of the products you are using as a resource
that can help answer any questions or concerns regarding its products.