What Is a Thermo Marker?
Color-Changing at High Temperatures
A thermo marker is a unique marker that changes color permanently when exposed to high temperatures, visually indicating areas that have become hot or were exposed to heat.
Applications in Screw Tightness Monitoring
Thermo markers can be used to draw on screw heads, serving as a visual temperature indicator and to check screw tightness. However, they are not suitable for outdoor use due to ultraviolet light sensitivity.
Common Uses of Thermo Markers
Monitoring High-Temperature Equipment
Thermo markers are applied to screws and components of boilers, piping, and electrical equipment prone to high temperatures. They are preferred over thermal seals due to their adhesive reliability.
Loose Screw Detection
By marking a tightened screw with a thermo marker, any shift in the line indicates loosening, providing a simple way to monitor screw integrity during operation.
Characteristics of Thermo Markers
Permanent Color Change with Temperature
These oil-based markers change from red to yellow at temperatures ranging from 105 °F to 175 °F. Once changed, the color remains altered even after cooling, except under extreme cold below -13 °F. This permanent change helps identify overheating areas or steam leaks and serves as a safety alert. However, the markers are not designed for very low temperatures, where they may revert to the original color.
Limited Weather Resistance and Adhesion
Thermo markers lack strong weather resistance and may fade in outdoor environments. They also do not adhere well to certain materials like rubber, packing tape, and Teflon. It’s advisable to test the marker on the intended surface before field application, as the ink is more prone to peeling compared to regular markers.