Preventing CIPP Resin From Curing Too Fast

Fast is generally good when it comes to resin cure times in the CIPP industry, but warm temperatures can cut that cure time too quickly and make it difficult for contractors to get the job done 

Preventing CIPP Resin From Curing Too Fast

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“What have you done to your resin? I added the hardener to the base, and it got hot before I finished mixing it. As I poured it into the tube to wet out, it got hard.”

Since we’re in the midst of the summer heat, this is a good topic to address.

If you are lucky, this scenario has never happened to you. If it has already happened, it’s one of those “learning from your mistakes” moments. We get calls every summer just like the one above. Conversely, we get calls from the same people in the winter asking us why the resin is taking so long to cure in ambient conditions. It's yet another learning moment.

Here’s the deal. Resin, like any liquid (water, paint or something else), dries faster in heat than it does in cold. Heat raises the pace of the drying, or curing, process. For example, with the Quik-Pox 30 resin that we sell, you can expect the resin to be workable at 77 degrees F for up to 30 minutes. Just raising the temperature a little beyond that cuts the working time from 30 to 20 minutes. Going the other way, at 63 degrees F, that resin would give you 50 minutes; at 50 degrees F, you’d get 120 minutes. As you can see, as the temperature increases, the work time decreases much faster.

If your resin was stored overnight with no temperature control and the next day has an ambient temperature of 100 degrees F, your resin may be well into the upper 80s or lower 90s. When the resin temperature is nearing 90 degrees F, it’s doubtful that you’ll get the resin hardener and base mixed before it begins hardening.

If you know of someone who has a resin that isn’t affected by temperature, let me know. Physics tells me you won’t find one. All liquids, whether resin, water, or paint, will dry faster if it is warmer and slower if it is cold.

Another aspect of curing rates is the quality of your mixing. If you use a low-speed drill with a mixing bit held in one spot in the bucket for the prescribed mixing time, the odds of getting a good mix of resin hardener and base is pretty slim. If you’ve cooled the resin and it’s thick, mixing may take longer than prescribed to ensure all of the hardener is fully mixed with the base to provide an even curing of the wetted out tube.

Knowing all of this, what can you do to make sure your resin doesn’t cure before you get it in the ground? Every convenience store sells ice. Many home improvement stores sell tubs that will hold two or three pails of resin. Add ice and water to these tubs, and place the pails of resin in the tubs. By doing this, you can effectively cool warm ambient resin. If you place the resin that you'll need the next day in the tubs overnight, you will be good to go right away in the morning.

Putting the resin buckets in the ice water for 20 minutes won’t lower the temperature enough prior to mixing. Then, you’ll be calling the manufacturer and asking what they did to the resin to make it cure too quickly. It’s summer now, and our enemy is heat.

About the author
John Heisler is the owner of Pipe Lining Supply and Quik-Lining Systems Inc. He has 20 years of experience in the CIPP lining industry and more than 40 years in the underground construction industry.


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