2. How do I determine what type of ink to use ?

3. What about the environmental impact of pad printing inks ?

4. What does hardener (catalyst) do to the ink ?

5. Can I mix different brands or series of inks and thinners together ?

6. How much thinner should be added to pad printing ink? Can I omit the thinner ?

7. How much ink does pad printing consume ?

8. What is retarder used for ?

1. Question : are pad printing inks available in any color I want ?

Answer : nearly. Visprox inks (available from Printex) come in over two dozen standard colors. Twelve of those colors compose a blending system which can be used to reproduce any of the Pantone coated series colors, well over 1,000 colors total. Our customers can purchase this system to do their own blending, or Printex can provide custom colors by the liter. We can also blend Day-Glo colors, UV-fluorescent and even phosphorescent colors. One big limitation of pad printing inks exists with metallics: metallic pad printing inks look like metallic paint, lacking the luster of foils.

2. Question : how do I determine what type of ink to use ?

Answer : most ink suppliers (Printex included) have enough applications data to recommend a suitable ink for the most common substrates. When in doubt, test it out. Printex has sample kits of Visprox Ink available specifically for this purpose. We also have an Online Ink Selection Chart you can consult. Click here to go to it.

3. Question : what about the environmental impact of pad printing inks ?

Answer : the most commonly-used pad printing inks are solvent based, and are considered paint-related materials by the DOT and the EPA. The solvent content means that they are flammable and that they outgass VOC's into the atmosphere. These type of inks must be shipped with proper labeling, and must be disposed of in the proper manner according to your regional environmental regulations. The advent of sealed inking systems (as featured in the COS, TC, and G2 series machines) has greatly reduced VOC emissions on the pad printing press.

4. Question : what does hardener (catalyst) do to the ink ?

Answer : hardener, which is also known a catalyst, reacts with ingredients in the ink to polymerize it. Practically speaking, this usually makes the fully dried and cured ink more resistant to scratching, rubbing and solvents. It also lends some adhesive properties to the ink (for instance, hardener is usually blended into ink which will be printed on metal). Hardener can only be used in an ink which is designed to work with it. A consequence of using hardener is a finite working life of several hours once blended, after which the remaining ink must be disposed of.

5. Question : can I mix different brands or series of inks and thinners together ?

Answer : it is possible, but not recommended. Manufacturers and vendors will have little or no information on the effects of experimenting in this fashion. Printex knows from experience that blending Visprox inks with anything other than Visprox thinner (of the same series) will result in unpredictable performance. Certain third-party pigments and additives will work in some pad printing inks, but it always best to consult your ink vendor before trying anything.

6. Question : how much thinner should be added to pad printing ink ? Can I omit the thinner ?

Answer : there is no single exact amount of thinner which should be added to pad printing ink prior to use. Typical for most inks is a blend of 2.5 parts thinner to 10 parts ink. Depending upon the application, the amount of thinner could be as little as 1/10 to as much as 4/10. As a general rule, the artwork to be printed determines the correct amount of thinner to use, with fine lines and details requiring more thinner than solid fills and bold lines. Determining the right amount of thinner for a particular job is best done through experimentation; too much thinner will result in a pale, smeary print. The vast majority of pad printing inks will have to be blended with some amount of thinner, as they are usually too thick straight out of the can to be used for pad printing

7. Question : how much ink does pad printing consume ?

Answer : this varies by the nature of the artwork being printed, but in any case the answer is: next to nothing. Ink consumption could actually be measured by printing a widget with a "typical" image, then weighing the printed part with an extremely precise scale and comparing that weight to the unprinted weight of the same widget. Printex does not own any type on measuring device which would be sensitive enough to do this. Even if such a device were available, the results would still be approximate, because it would not take into account the factors of solvent evaporation, ink loss during plate changes, color changes, cleaning, and the occasional spill, which all contribute to ink consumption. In the case of catalyzed inks, consumption is a little more obvious, since all remaining catalyzed ink is disposed of at the end of its pot life.

8. Question : what is retarder used for ?

Answer : retarder is a type of thinner with a very slow evaporation rate. It is used to extend the gel time of the ink and counteract premature drying. Typical reasons for using retarder would be very hot, dry climatic conditions, a slow machine cycle time, or the need to reproduce very fine details (which tend to dry quickly on the printing pad). Retarder should be added carefully in small amounts, as a little retarder tends to have a big effect on ink dry time. Since retarder is a water-thin liquid, it lowers the viscosity of ink just like thinner, and so when it is needed it should be used in lieu of some amount of the thinner content (under certain conditions, retarder may be used in place of thinner).