Warm Weather – Avoid Flash Setting
Summer is in full swing. While the warm weather, time with friends and family, and summer activities are all welcome, the warmer weather can also create challenges associated with placing refractory materials. As our monthly safety flier indicates, heat stress can be dangerous to workers, however, the warm weather can also be dangerous to monolithic materials such as castables, plastics, and mortars. The warm temperatures can mean faster set times as well as an increased risk of “flash setting.” Flash setting occurs when monolithic materials rapidly rigidize. Installers depend on a material’s workability in order to transfer it from a mixing location to its final destination as well as in order to achieve the desired shape, thickness, physical properties and layout. When materials flash set it can lead to damaged equipment, wasted material, re-work, and undesirable as-installed physical properties.
While installers should be wary of flash setting throughout the year, the increased summer temperatures significantly increase the probability. Fortunately, there are ways to minimize the risk:
- Store materials in a cool location out of the sun. It may be necessary to pre-arrange storage of material at the work location to avoid improper storage or coordinate just-in-time material delivery. The material temperature, as well as the ambient temperature, play a roll in the set time of the material.
- Verify the temperature of mixing water. During the summer months, water sources may be out in the sun or exposed to much higher temperatures than during other times of the year. If the water being added to a mix is hot, it will increase the rate of the reaction within the mix.
- Pay close attention to equipment layout. The faster that the material travels through pipes, hoses, buckets, etc. the lesser the wasted workability time between the mixer and the materials installed destination.
- The addition of retardants such as citric acid may significantly increase the workability time. Be sure to check with the material manufacturer prior to the addition of citric acid to the mix. This may not work in some circumstances and the addition of too much citric acid could decrease the as-installed materials’ physical properties or prevent the materials from setting up at all.
For more information or insight on how you can prevent flash setting material from negatively impacting your next refractory project, reach out to Schad today.