Posted by Mary Yaeger - 8/15/2017
There are two main types of ink that
get used for textile printing – plastisol and water based. While plastisol is
more widely known and used, the desire for a more eco-friendly shop has brought
water based screen printing into the spotlight. What you will find is that both
types of inks have their incredible advantages, but they also have a few drawbacks.
To get started, let’s discuss mesh.
The mesh count you use is one of the most important factors to consider when
printing (no matter what method you choose to print). Here is a short outline
of the different mesh recommendations for inks:
- 24-40 mesh for Glitter inks
- 60-80 mesh for Shimmers and thick
white underbases
- 86-110 mesh for Metallics
- 110 mesh most popular for light
colors such as white ink
- 160 mesh most popular for black ink.
It holds more detail than 110, but less ink will pass through the screen.
- 200-230 mesh holds high detail
though the ink may need to be reduced. This mesh is great for water based inks.
- 230-305 mesh is mostly used for
super fine detail half tones and CMYK process prints. This mesh is also great for
water based inks.
Plastisol Ink
Plastisol is the most popular ink in
the industry. It is easy to use and promoted as “user friendly”. Plastisol is
not water soluble so you don’t have to worry about it drying in the screen.
These inks are generally used right out of the container. No mixing needed.
Plastisol is perfect for getting the opaque look on dark garments. It is
formulated for printing on light and dark garments. Since plastisol does not
dry in the screen, there is no worry about ruining a screen or wasting product.
Plastisol does not “dry” when exposed to air. Plastisol has to be cured between
280-350F. The greatest advantage of this is being able to reuse the ink for
multiple jobs. As long as the ink has not been contaminated by dirt, lint or
other ink, the plastisol can be scooped off of the screen and placed back in
its container.
Likewise, if you leave the ink
container open for several days, the ink will be ready to use when you come
back. You can also leave the ink in a screen for several days without worry of
clogging or ruining the stencil. Plastisol also has the capability of wet-on-wet
printing which means increased production times – saving your shop time and
money.
It is generally recommended that you
store plastisol at room temperature. This means keeping your shop temperature
controlled. If the ink gets too hot (above 90F) there is a possibility it could
start the curing process in its container. A big disadvantage of printing with
plastisol is that has tends to have a greater hand-feel. This is a disadvantage
because most t-shirt enthusiasts desire a vintage look and soft hand-feel to
their shirts. Another thing to note about plastisol is that it should not be
ironed. The iron could “re-melt” the plastisol and smear ink on your garment.
If you would like to dispose of any
contaminated ink be aware that uncured plastisol is considered a hazardous
waste and should be disposed of according to your community guidelines. When
plastisol is cured, it is not considered a hazardous waste, but make sure you
still properly dispose of it.
Water Based Ink
What plastisol can’t achieve is
where water based ink steps in to play. Water based inks are great for
achieving that vintage soft hand-feel that is desired by most. Water based inks
soak into the fabric instead of standing on top. Water based inks are promoted
as more “eco-friendly”, but it is important to keep in mind where you are
getting this information from. Just because it is labeled as eco-friendly, does
not mean that it isn’t free of “co-solvents” that could be petroleum based. The
reason these co-solvents are used varies, but one of the reasons is meant to
reduce the time and heat necessary to cure the ink on the fabric.
While water based gives most people
the look and feel they want in their prints, there are a few factors that deter
people from even trying it in the first place. Unlike plastisol which is ready
to use right out of the container, water based ink requires a little bit of
mixing math. Water based inks start out as two separate products – pigment and
base. You have to add the right amount of pigment to the right amount of base
to get the desired color. There are also several additives that you must
consider for each type of print.
With a name like water based it is
easy to assume that curing would be a simple process because in reality all you
are doing is evaporating the water to cure. At a craft level, this might not be
too bad. Water based inks can air dry, but not in enough time for high
production jobs. For shops that are printing at an intermediate to high
production level, the dryers that are required for water based inks are
typically larger than the dryers used for plastisol. To help the ink cure
faster, you can add what is called a “catalyst” to the ink. The catalyst allows
for a fast dry time and ensures an even dry over the entire printed area. The
disadvantage to using a catalyst is that it greatly reduces the life span of
the ink. When you add a catalyst to water based ink the shelf life is limited
to 4-12 hours.
Water based ink tends to dry in the
screens if not tended to constantly. For this reason, it is important to keep a
spray bottle full of water nearby to keep the ink wet. If the ink dries in the
screen it will clog the mesh and ruin the screen. It is also important to
consider the type of emulsion you are using. Water resistant emulsion is a MUST!
Water based inks will melt or eat through any other type of emulsion. This will
end up destroying your stencil and setting your print job back.
