How to Anchor Bolts in Concrete Using Anchoring Epoxy
Anchoring handrails or securing any object to concrete or masonry using threaded rods, rebar, bolts or dowels requires a high-strength, permanent bond, especially applications that will be subjected to heavy loads or vibration. Depending on your specific anchoring application, an anchoring epoxy will usually fit your project requirements.
An anchoring epoxy is a one hundred percent solids, two-component epoxy in a single cartridge with a working time of about five minutes. An anchoring epoxy’s non-sag characteristics make it ideal for both vertical and horizontal use.
A high-strength anchoring epoxy is also a one hundred percent solids, two-component epoxy in a single cartridge, but its extended working time makes it particularly suited for applications where multiple railings must be set.
High-strength epoxy also has a pullout strength of over 30,000 PSI, making it ideal for heavy-duty applications.
Anchoring epoxies have a cure time of just two hours for normal anchoring epoxy and three hours for high strength anchoring epoxy.
How to Anchor Bolts in Concrete with Anchoring Epoxy
First, drill a hole, a sixteenth of an inch to a quarter of an inch larger than the diameter of the threaded rod or railing you are setting. The hole depth should be a minimum of four and a half times the diameter of the bolt, so half inch threaded rod would require a hole depth of 2 and a quarter inches. Increasing the depth of the hole significantly increases the tension load that the anchored rod can withstand.
After you have drilled the hole, blow out the dust from the bottom of the hole. Cans of compressed air work well for this task. Then, use a nylon brush to remove any remaining debris from the hole, rotating the brush a quarter of a turn as it’s removed from the hole.
After brushing, use the compressed air to remove any remaining dust.
Once the hole is properly prepared, insert the anchoring epoxy cartridge into a caulk gun.
It is highly recommended that a high quality, high strength dispensing gun be used because of the significant amount of force required to dispense the two-part epoxy through the static mixer nozzle.
Then, remove the plastic cap from the tip of the cartridge. This should be easily accomplished with your fingertips, but pliers may be necessary.
Dispense a small amount of epoxy into a disposable container, until you get an even flow of both the black and white material. Then attach the static mixer nozzle on to the cartridge and dispense enough epoxy until a consistent gray color is achieved, with no streaks.
Place the tip of the dispensing nozzle into the bottom of the hole and fill the hole about five eighths full, while slowly withdrawing the nozzle. Then, insert the threaded rod or rebar to the bottom of the hole, while turning clockwise. Remove any excess epoxy from around the hole with a putty knife or a piece of cardboard. Leave the anchor undisturbed, until the cure time has passed.
Anchoring epoxies have a unique two compartment plastic cartridge that is completely discharged when the cartridge plunger is dispensed halfway. Upon completion of your anchoring project, simply remove and discard the static mixer nozzle and replace the cartridge cap.
Anchoring epoxies can be stored for up to two years.