As if you don't have enough things to learn as a newcomer to screen printing, the choice of ink type can make or break a project. Now, the different series from all the major screen printing ink manufacturers all specialize in various things, and that is beyond the scope of a simple blog article, but I will attempt to give you an overview of ink types and their uses in your shop.
One of the main things to take away from this writing is that the substrate, or material you are printing to, is going to be the most important factor in choosing ink type. When you see an ink labeled as a general purpose ink, that ink is typically formulated for use on cotton and/or 50/50 shirts and materials. Many shops will use this ink about 75% of the time, and most smaller jobs where customers want the best possible price will be printed on normal quality cotton or cotton blend shirts. These 'plastisol' inks are durable, easy to work with, and also some of the more economical inks that you can have in your shop.
When a customer wants a job printed on polyester or athletic wear, there are special polyester inks formulated just for that. The biggest problem with polyester materials is dye migration. That is, when you heat the garment up in the dryer to cure your ink, the heat will try to release the dye in the actual material. This can 'mix' or blend in with your ink and cause your ink to have a faded, splotchy look that is typically not desirable. The solution could be to use special inks formulated for use on polyester garments. These inks are more resistant to dye migrations issues (although they are not immune to some problems themselves). You also may find benefit in using an underbase with this material.
an illustration of dye migration issues. note the 'faded' appearance of the shirt on the right.
Silicone inks are a relatively new type of screen printing ink, and are available from us here at ScreenPrintingSupply.com. Silicone inks have a much shorter shelf life and, in the current state of the technology, each color has to be mixed on site using a base and toner system. The benefits of silicone inks are numerous, however. It is an extremely durable ink, especially in athletic garments. It has tremendous elasticity that cannot be matched by any other current ink type, making it ideal for stretchy garments. It has a smooth, soft-hand feel that is appealing to the touch. Lastly, silicone inks cure at a much lower temperature than standard plastisol inks, typically at a lower temperature than most polyester materials will release dye, negating dye migration issues altogether. Note that this may depend largely on the quality of your polyester garment, as lower quality poly garments may release dye at even lower temperatures.
Then there are all varieties of 'specialty' inks. These are inks that are beyond the scope of standard plastisol, poly, or silicone inks in that they normally have some feature that sets them apart visually or to the touch. These can include glitter inks, puff inks, reflective inks, etc. There are many additives that can be purchased for plastisol inks to achieve many of the same benefits, but there are inks with these features that are ready to use.
Air dry inks may be your choice for printing on any material where the heat of curing may cause problems or applying heat is impossible. Such inks are commonly used for printing signs such as campaign or realty-type signs, plastic bags, and many types of promotional items. Air dry inks are generally quite a bit thinner than standard screen printing inks, so you should typically start with a much higher mesh-count screen (we recommend starting with a high-200 or low-300 mesh). As the name implies, these inks will fully cure without applying heat, so care should certainly be taken to reclaim your screens soon after finishing the job to avoid a much harder reclaim later. Our full line of air dry inks all include a full description of substrates that the ink works well on, so be sure to read carefully before making a decision.
Lastly, take some time to make yourself aware of many of the different types of ink additives, and they will add flexibility to your printing capabilities. Products such as Nylobond enable screen printing to nylon-based products such as umbrellas. There are thinners for use in ink that may be a bit thick, puff additives to add depth and texture to your print, and so forth.
So there you have it, a very brief overview of some of the major types of screen printing inks. Again, let your substrate dictate your ink type, but it will benefit your shop if you have experience with all of these types, and it will add capabilities and experience to your shop reputation that competitors may not yet have. All of these ink types and more are available at Texsource at 888-344-4657, or online at www.ScreenPrintingSupply.com.