The QCT uses 100% condensing humidity to simulate and accelerate the type of damage caused by rain and dew on metals, paints, and organic material. It is fast, easy to operate and low cost. The QCT reproduces the effect of outdoor moisture with the universal corrosion agent - Aggressive Water.

The QCT accelerates moisture attack by increasing the moisture temperature. A 10^oC increase can double the rate of a reaction, 30^oC can increase it tenfold. The QCT has automatic controls to regulate condensation rate and to allow you to cycle from wet to dry on any desired program.

The QCT can be used to replace water immersion and ordinary (non-condensing) humidity tests. The QCT has been proven by research of the Cleveland Society for Paint Technology and by use in hundreds of laboratories since 1965.

Condensation Duplicates Outdoor Moisture

Water, in one way or another, is the common enemy to most materials of construction. With some exceptions, protective coatings are designed to control the action of water. The corrosion of metals, the deterioration of cellulosics, the disintegration of siliceous structures and the decomposition of organics all involve some interaction of water whether as a vapor, liquid or solution. Protective coatings function basically by providing a barrier between an impermanent substrate and an aqueous environment.

Condensation, in a normal atmosphere, is water that has been distilled from impure water, mixed with the atmosphere, thus becoming saturated with dissolved air containing oxygen, rain, dew and fog are all condensation: distilled water + dissolved oxygen. Such water is sometimes called "aggressive" water. As it diffuses through or contacts a material or coating, it carries oxygen with it. Exposing materials outdoors subjects them to "aggressive" water but the amount of water and water temperature are not controllable.

The QCT tester accelerates outdoor moisture attack, because it supplies a controlled amount of "aggressive" water to the test surface under temperature-controlled, cyclic or constant conditions.

Variable Exposure Cycles

The QCT allows the user to thermostatically control heat input for both the water heating and for the dry-off air temperature. Exposure temperatures can be set to range from room temperature to 70°C (158°F). Coupled with an automatic cyclic timer, this system allows the selection of almost any desired exposure cycle. Wetness can be an invisible dew a few degrees above room temperature or a continuous, high-temperature running condensate.

• To simulate the service conditions of some indoor storage environments, a program of light dew followed by dry-off can be used
• Freezing cycles accelerate some failures, possibly from ice crystals rupturing adhesive bonds. To achieve this, test panels can be removed from the QCT unit while wet and usually frozen immediately to avoid any loss of water
• Consult the appropriate test procedure for the exposure cycle most appropriate for your particular application.

QCT is Accepted

The QCT is used throughout the world by paint manufacturers, chemical companies, oil producers, automobile and appliance manufacturers, and research laboratories.

Features

• Improve correlation with outdoor results
• Fast and Versatile
  • Screens automotive paints for blister resistance over a weekend at 55°C (130°F).
  • Evaluates oil-based rust inhibitors in less than 120 hours at 38°C (100°F) and rates effectiveness of mill-applied oils in only a day.
  • Tests the surface reactivity of cold-rolled and galvanized steel in hours.
  • Tests wood finishes for moisture and mold resistance (mount painted side down).
  • Can be used as a "blister box" for painted wood finishes (mount painted side up).
• Easy to Use, Simple to Install
  
  The QCT can provide instant blister or corrosion testing. Just plug it in and add water. Place the unit anywhere - office, lab, or plant. The heat and water vapor produced by a QCT is about the same as that produced by one additional person in a room.
  
  The test panels on a QCT Condensation Tester may be inspected as often as you want without altering test conditions on the wet or the dry part of the cycle. Just remove the panel and put a blank in its place.

Standards Specifying the QCT:

• ASTM D4585, Testing Moisture Resistance of Coatings with Controlled Condensation
• ISAO 6270-1, Paints and Varnishes Humidity (Continuous Condensation)
• BS 3900, Part F9, Determination of Resistance to Humidity (Continuous Condensation)