Set Control Guidelines

Technical Bulletin: SET Control® Guidelines

The setting time of Rapid Set® Eisenwall® has been optimized to provide adequate working time for material application/pumping, along with rapid strength gain for structural integrity. However, the material is temperature sensitive and best results will be achieved if the following guidelines are followed.

The most important factor in determining set time is the temperature of the mix — as soon as the material is dumped into the hopper. The temperature of the mix is roughly an average of the temperatures of the cement, sand, and mixing water, plus 3 to 5 degrees F. For example, if the cement, sand, and water are all 70°F, after adequate mixing, the temperature of the mix will be between 73° and 75°F. However, even though the outside temperature is an even 70°F, the temperature of the cement, sand and water can vary widely.

The temperature of the cement and sand can be quite low (sometimes as low as 35°F) if allowed to sit outside overnight in cold weather, and quite high (over 100°F) if allowed to sit in the hot sun all day.

While water coming directly from a source such as a fire hydrant is normally quite cooler than the outside temperature, water flowing to the mixing site in a dark colored hose in the hot sun can be significantly warmer than the outside temperature.

The following table provides starting guidelines for the addition of SET Control® retarder. The batch size is two sacks Eisenwall and 36 – 44 no.2 shovels washed plaster sand.

 

Temperature of mix when dumped into hopper Number of packets SET Control® to add to the mix (per 2 sacks)
below 70° F none
70° F 1
77° F 2
83° F 3
88° F 4

*always add SET Control to the first batch of plaster based upon an estimated average temperature.
Adding too much SET Control can cause slower strength gain and excessive plastic shrinkage. However, not adding the correct amount of SET Control can cause the material to set up in the hose.


TechBulletinB_1Important Points:

Other factors such as the wall being in direct hot sunlight, or the pumping hose lying on hot black asphalt in direct sunlight can cause the material to set up faster than normal.

Precautions such as shading the sand or cement from the sun can help lower batch temperatures.
Adding just enough SET Control to provide adequate working/pumping will achieve the highest quality results.

Communication between the workers on the wall and the plaster tender will allow the SET Control dosage to be fine-tuned as the job progresses.

If you require further assistance please call CTS Cement Manufacturing Corp. at 800-929-3030.