Chopping and patching

 

In general, bolts should be replaced by reusing & expanding the original hole. There are some exceptions to this: when the old placement is in rock that is poor quality, removal of the old bolt is impossible, or severely overhanging terrain creates safety and efficiency challenges. In these cases, it is important to cut the old bolt and patch the hole as cleanly as possible.

 

tools for the job:

  • Hacksaw or battery-operated angle grinder

  • Hammer

  • Epoxy: putty style epoxy tubes are easily mixed in small batches and easy to clean up, can be purchased in different colors to match the rock type

  • Ear/eye protection if using grinder/cut-off wheel

  • Wrenches or ratchet driver/sockets: appropriate size for bolt being removed

  • Breaker bar/handle extension for driver

  • Metal punch

  • Metal cutting bit

 

chop and patch:

  • If removing a sleeve bolt it can sometimes easily be unscrewed, leaving a hole to fill with epoxy.

  • When a sleeve bolt is seized in place, you may be able to shear the head of the bolt off using your breaker bar.

  • When the head of a sleeve bolt is stripped, you will need to use a cut-off wheel on your grinder: scoring vertically until you get through the head, then cutting from that groove at an angle to the left and right works well to remove the head. Then use a punch to force the bolt shaft back into the hole and create a void to fill with epoxy.

  • If chopping a wedge bolt you can often use your breaker bar to over-tighten and shear the bolt, then use a punch to force the bolt shaft back into the hole and create a void to fill with epoxy.

  • Scoring a wedge bolt deeply with a hacksaw or grinder close to the rock then hammering from side to side until it shears can also work, be careful not to scar up the rock around the placement.

  • For glue-ins and wedge bolts that cannot be driven back into the hole to create a void for epoxy, you may have to remove some of it with a metal cutting bit to create a void to patch with epoxy.

  • Match your epoxy color to the rock and carefully patch to blend the edges into the rock. If your epoxy does not match the color of the rock you can mix in a small amount of rock dust/sand that better matches the rock.