Failing to cap a crack properly before injecting epoxy resin can cause a leak that wastes costly resin. Why do setups leak? Usually it's because of incorrect capping methods. Using the right method prevents leaks.

STEPS FOR CAPPING THE CRACK SURFACE

  1. Clean the surface: To bond well, caps must be applied to a sound, clean surface.
  2. Select the right cap material: For most work, a high-modulus, gel-type epoxy should be used. Also, a fast cure time--2 to 3 hours--is desirable if you want to cap and inject epoxy on the same day.
  3. Carefully batch and mix the epoxy cap material: Accurately batch the two components for the cap. If the ratio is off by 10%, presume that the strength will be short by at least that much.
  4. Avoid skips and thin spots in the cap: Skips are areas at the surface of the crack where the cap doesn't bond. These voids allow injection resin to flow under a larger area of the cap, often lifting it off and causing a leak.