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 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.