Ink mixing is a basic but very important step to achieve a quality imaging with screen printing or pad printing. If it is not done properly, the entire printing process can get very frustrating and, in turn, may cause a loss of production and a waste of valuable time and energy.
Before you start, it is essential that you be using the proper equipment. Unlined mixing cups (no wax), mixing sticks and a quality electronic scale with an accuracy of .1 grams are all very important. Without these items, ink mixing becomes guess work, causing the quality and precision of the print to suffer.
Step by Step Ink Mixing:
1. Zero or tare out the scale (make sure it is on a level surface).
2. Add the ink to a mixing cup. Try not to use less than 40 grams as it will not flow well in the cup or inkwell once mixed.
3. Add appropriate hardener ratio (4:1 for 1000H = 25%, 20:1 for HGL = 5%).
4. Mix these two ingredients completely. Note: pad printing and screen printing inks that are activated with hardener 1000H/1000KGL have a pot life of about 8-10 hours.
5. Begin adding thinner at a ratio of about 5%-10% then re-mix.
6. Continue to add thinner at a "drop by drop" rate until a working viscosity is achieved. Adding all the thinner at once tends to "shock" the ink. Typical mixing ratios are 15% thinner to the weight of the ink. Remember, it is easier to add than to take away. This also helps to prevent ink over thinning.
Please note that Sapphire Pad Printing & Screen Printing Inks are highly opaque and take more thinner than most inks. The adjustment of the viscosity of the ink depends on the quality of thinner that is being added. Generally you should never exceed 20-25%; however, dilution varies from series to series.
If you follow these simple steps it should help to improve your pad or screen printing process. If you ever have any questions please contact me, Pete Baxer, at 1-978-646-8980 and I will be glad to help you.
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Pete Baxer, is ICN's Chief Ink Specialist and Tech Support Manager. Before joining ICN, Pete worked as a production manager for a promotional products company for 8 years.
