A recent resin bolt failure in Taiwan has highlighted the need for a through understanding of what aspects of a resin dispensing system can fail and how it in turn causes a suspect bolt.
I follow the recommended Hilti procedure and have added additional checks when using Hilti RE 500 and it prevents improper mixing, amongst other problems:
1. Check dispenser and foil pack holder for functionality
THIS ELIMINATES THE DISPENSER AS A CAUSE OF FAULT
2. Open foil pack and inspect pack for separation of each component tube from the plastic head.
A CAUSE OF INCORRECT MIXING
3. Check the expiry date on the foil pack head
ELIMINATES COMPONENT AGE AS A FAULT
4. Load dispenser
5. Pump dispenser into a transparent plastic bag until both components are being dispensed.
THIS CONFIRMS THAT 1) BOTH COMPONENTS ARE BEING DISCHARGED 2) CONSISTENTLY WITH EACH TRIGGER PULL
6. Inspect mixer nozzle, then attach to dispenser
ELIMINATES IMPROPER MIXING FROM A DAMAGED, BLOCKED OR INCORRECT NOZZLE TYPE
7. Discharge the required trigger pulls (once the nozzle is already primed-includes the use of any tube extension) into the transparent plastic bag (typically foil pack bag)
CONFIRMS RESIN IS 1) MIXING 2) COLOUR CHANGE 3) PROVIDES A SAMPLE TO CHECK FOR EXOTHERMIC REACTION LATER AND ONCE FINISHED
8. Tag the route / tape the initial bolts etc. Whatever your procedure is to warn others of the need for the resin to cure.
9. I keep both the bag and mixer nozzle for later inspection.
THE BAG AND NOZZLE PROVIDE CONFIRMATION OF SUCCESSFUL CURING. YOU CAN SNAP THE NOZZLE AND INSPECT THE CURED RESIN IN THE COMFORT OF YOUR OWN HOME LATER