Prime Practices

Prime Practices

Sealing Gushing Leaks with Prime Flex 920 in Quick Mix Cartridges

Call: 1-800-321-7212

Injection of large defects in below-grade concrete and/or masonry structures to seal gushing or excessive water leaks. 


Problem: A large crack or defect (including a failed joint) in a below-grade concrete or masonry structure that is located in a high groundwater area allows for large volume infiltration creating gushing leaks in the structure.



Locate the places where water is infiltrating the structure. In scenarios where large volumes of water are gushing through the structure, it may be necessary to temporarily dam the defect (see Activated Oakum Technique) in order to precisely identify the type of defect that is present within the structure.



In some cases the actual defect itself may not be conducive for conveying material. Once the defect has been identified, drill a 3/8” diameter hole directly into the defect for installation of the static mixer that will be used to inject material. When injecting wide cracks or joints, it is only necessary to penetrate the crack or joint until water begins leaking through your injection hole. It is not necessary to drill through the structure entirely to the exterior.



Prime Flex 920 is packaged in a dual 750 mL by 75 mL cartridge system (the 75mL “B” tube contains Kick Fast Kat). The cartridge requires a 10:1 ratio-capable pneumatic gun to dispense the Prime Flex 920.

  • Attach the air hose to the dual cartridge injection gun and turn on the air compressor.
  • Remove the Prime Flex 920 cartridge from the sealed plastic packaging.
  • Unscrew the included retainer nut and remove both half moon plugs from the cartridge tip.
  • Attach the flow restrictor (included in a separate plastic package) to the cartridge tips.
  • Firmly attach the 1/4” static mixer over the flow restrictor and down onto the cartridge tips.
  • Finally, slide the retainer nut over the static mixer and hand tighten.
  • Push the thrust pin on the pneumatic gun to the “reverse” position and press and hold the trigger while installing the cartridge into the injection gun. Ensure the 750 mL resin side is in line with the 750 mL plunger disc and the 75 mL Kick Fast “B” side is in line with the 75 mL plunger disc.
  • Once cartridge is in place, release the trigger.
  • When material is not being injected, hold the gun and cartridge in a vertical position with the static mixer pointed upward.



  • Prior to injecting, ensure the regulator on the air gun is turned fully to the right.
  • Push the thrust pin to the forward position.
  • Insert the 1/4” mixer directly into the leaking 3/8” injection hole.
  • Immediately press and hold the trigger. Do not release the trigger until the cartridge is completely empty. This process will take approximately 12 –18 seconds.
  • Release the trigger when the cartridge is empty. Pull back the static mixer nozzle partially, leaving it only 2 – 3” in the hole for approximately 90 seconds and then remove.
  • Repeat process until leak is sealed.
  • In the event of material refusal, use the “Activated Oakum Technique” to assist holding the Prime Flex 920 material in the defect.



Remove empty cartridge, static mixer and retainer nut from injection gun and discard. Prime Resins recommends using Prime Plug to fill the injection holes to a depth of 1” after injection is complete.


 Safety Considerations:

  • Carefully read MSDS/SDS prior to handling any chemical.
  • Always wear safety goggles when drilling, grinding, flushing, injecting or handling resins.
  • Always wear protective clothing, chemical resistant gloves and safety goggles at all times when handling resins. Blowouts can occur when injecting resins at high pressure. Prime Plug contains cement powder, which has a very high pH and may cause burns to skin or eyes.
  • Be aware of potential electrocution hazards when working with power equipment in wet environments. Keep water away from electrical cords and electrical equipment.
  • Make sure no loose clothing can come into contact with moving mechanical equipment.
  • Follow all OSHA confined space entry requirements where applicable.
  • Polyurethane resins contain isocyanates, which can cause respiratory irritation. Use mechanical ventilation in confined spaces.
  • Keep first aid kit (eye wash, bandages, etc.) present on site with easy access.


Materials List:

  1. Prime Flex 920 cartridges with Kick Fast
  2. Prime Plug 1, 2 or 3
  3. Dry, unoiled oakum


Equipment List:

Injection gun
Air compressor
Air hose
Hammer drill
3/8” concrete drill bit
Empty 1 – 2 gallon pails





Activated oakum technique