The Express Test Pen 38 mN / m- is used for the quick detection of pretreated surfaces. It is not suitable for the systematic measurement of surface tension.
With the test pen, like a normal felt-tip pen, a line is drawn on the material to be examined
applied. If the line remains as a closed area within the next 2 seconds, the material is pretreated with at least 38 mN / m and is printable. If the line contracts within 2 seconds or if it forms a spotty structure, the material has not been pretreated or has only been inadequately pretreated. The ink dries within seconds.
The substances in the ink are "non-toxic"