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March 9 - March 13, 2015

How do you know when pot life has expired? Can you extend pot life and, if so, how?


Selected Answers

From Tom Schwerdt of Texas Department of Transportation on March 12, 2015:
The safest way I know of to extend pot life is to reduce the temperature. An epoxy at 90 F will have a much shorter pot life than an epoxy at 50 F. In hot weather, simply storing your kits in the shade instead of the sun can have a noticeable effect on pot life. Storing the kits in controlled conditions is even better. After mixing, the bigger the container of epoxy, the shorter the pot life. As the epoxy cures, it heats up. As it heats up, it cures faster. Bigger containers typically hold the heat better than smaller containers. Plastic containers typically hold the heat better than metal containers.

From DHIRENDRA KUMAR of INDIVIDUAL on March 11, 2015:
Under the controlled conditions of a laboratory, pot life can be determined by recording viscosity with respect to time elapsed after the two components have been mixed. Once the viscosity rise becomes exponential, the duration can be termed as pot life. Under field conditions, pot life can be noticed when application by brush becomes difficult and the coating is non-uniform. In case of spraying, pot life is the duration after which one requires larger force to spread the coating. Increasing the pot life by addition of solvents or diluents is not recommended, as coating adhesion will be affected.

From David Zuskin of Indepedent on March 10, 2015:
Sarah makes good points. Most mixed 2-part (2K) coatings will increase temperature in the container as the end of pot life approaches. (Some may start "smoking.") An infrared temperature gun is a quick way to check, but a stem thermometer will work also. A spray painter (airless spray) may note the width of his spray fan decreasing,requiring an increase in pressure to maintain the fan. Sprayers may notice the temperature of the spray gun increasing. Of course, if you are having problems with pot life, you may want to switch to plural component spray equipment (if the coating manufacturer permits) where the only pot life concern is the material in the hose and spray gun beyond the static mixer.

From Michael Quaranta of OPERATIONS 40 on March 10, 2015:
Are you kidding? This question is directed at two-component standard epoxy, and you've got to read the directions. After you mix the two components, the instructions are clearly stated: "Tilt bucket to pour the product onto the floor where you are intending to apply the coating" (?). Then spread as fast as you can with screed in the recommended 20-square-feet-per-bucket mix. Repeat this procedure until the intended overall surface has been coated. You can immediately tell if the pot life has expired because it will make the bottom of the bucket its permanent home.

From Sarah Geary of RockTred on March 9, 2015:
I am not sure which system type you are talking about, but in most cases you will know when pot life has come to an end in a 2K system when the material becomes thick in the mixing vessel. The material will no longer be free flowing when poured out of the mixing vessel. There are a number of ways to extend pot life; however, I recommend you contact the manufacturer for product-specific methods of pot-life extension. Many times there are better recommendations than normal methods or there may be limits to the amount of adjustments you can make to the system.

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Tagged categories: Asia Pacific; Coatings Technology; EMEA (Europe, Middle East and Africa); Latin America; North America; Pot life


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