Screening, the key to durable organic paint / Part 1

Today, organic paints can withstand more than 500 cycles in a domestic dishwasher, which is equivalent to more than 5,000 cycles in an industrial dishwasher (e.g. our HGC 8 series). However, to ensure that this is always the case, it is essential to ensure that the paint is well-screened.

Don't worry, it's nothing complicated. Basically, just ensure that the product to be fired is heated to a temperature of 170 to 200°C. (We stress that the minimum temperature is 170°C, not one degree less!). We need to heat/reheat the glass to this temperature for about 10 to 30 minutes. The time also depends on what temperature you are firing (or drying) to.

At 170°C a longer warm-up time will be required (approx. 20 min), at higher temperatures the time can be shortened (e.g. to 190°C for 15 min).

However, the nature of the product also affects the time. By nature we mean mainly the design of the product. Is it thin-walled glass? Then a shorter time will be sufficient. On the other hand, a longer time will be required for products with a greater glass thickness.

If the product combines both thin-walled parts and thicker glass parts, it will be necessary to check the temperature in both parts of the product. This is because there is a risk that the thin-walled part is well fired (or dried) but the thick-walled part has not been heated high enough or long enough (or both). If the temperatures in these parts are different, the crosslinking will not be sufficient and the chemical and mechanical resistance will then be reduced.

When setting the firing temperature curve, however, it is also necessary to ensure that the temperature is not exceeded. At temperatures around 200°C some pigments change colour and may burn out completely.

We'll cover how to set the temperature curve correctly and how to check the quality of the crosslinking in part 2 of the article Crosslinking, the key to durable organic paint.

If you don't have time to wait until the next Newsletter and need help with verifying the firing quality of your products immediately, call us on +420 571 612 420

This topic is also part of the material discussed in our new seminar on glass decoration with HGC organic spray paints (AQ or ColorSpray for glaziers)

The article was written by: David Batla
CEO of GDS Technology s.r.o.