Garnet Blasting Procedure

Overview:

Garnet blasting is an effective method for cleaning surfaces affected by fire or smoke damage, particularly in masonry and structural materials. This procedure outlines the necessary equipment, chemicals, and steps to safely and effectively perform garnet blasting.

Equipment Needed:

  • Utility Trailer with Tie Down Straps and Tow Vehicle

  • Garnet Blasting Machine (Apollo): For propelling garnet abrasives at high pressure.

  • Air Compressor: To provide the necessary air pressure for the blasting process.

  • Red Blast Hose: A durable hose (2 sections) to provide compressed air to the Apollo system from the compressor.

  • Nozzle/Trigger/Gray Shield: The gray shield line utilizes garnet sourced from Apollo. The trigger system and nozzle are engineered to direct the garnet efficiently onto the surface undergoing blasting.

  • Gas: Premium gasoline in container.

  • Funnel: For adding garnet to the Apollo. It has a screen strainer and is specific to this purpose.

  • 5-Gallon Bucket: Used when adding garnet to the Apollo.

  • Contractor Bags: Used for sweeping up garnet debris. Do not save.

  • Shop Vacuum: To collect debris and dust post-blasting.

  • Snow Shovel: For initial cleanup of garnet on the floor.

  • Leaf Blower: To assist in cleaning after blasting.

  • Brooms/Dustpan: For final cleaning; regular broom and push broom.

  • Containment: As needed, also consider zip poles or stapler.

  • Personal Protective Equipment (PPE): Gloves, Full Face Respirator, and coveralls. (Note: Do not use MaxAir system; garnet contaminates the headset requiring replacement of many components.)

Chemicals Needed:

  • Garnet Abrasive: A natural mineral used for blasting. 25kg, 200 mesh bags.

Step-by-Step Procedure:

Operation:

  1. Pre-Check

    • Fuel up the compressor. (Note: If it can be left inside the trailer all the better, keep well ventilated.)

    • Check the oil.

    • Add garnet to Apollo system. (Note: Take great measure to keep the unit and garnet dry.)

    • Connect red hose(s).

  2. Powering the Compressor:

    • Switch on fan on compressor.

    • Add air mover to blow on compressor as needed (e.g. hot ambient conditions)

    • Pull choke.

    • Turn switch to START. (Note: May take several seconds.)

    • When revs change (audible) push in the choke.

    • At red hose connection, turn ON (lever) the air flow. RPMs will change (audible).

  3. Garnet Blasting:

    • Using trigger system (one is at nozzle, another model is at Apollo unit), activate garnet flow.

    • Pressure should initially be set to 2 to 3 bars, adjust up or down as needed for the specific job.

    • Periodically, at the compressor, release pressure at the water separator to expel water that builds up during operation.

    • Periodically, at the Apollo, release pressure at water separator to expel water that builds up during operation.

Note: If operation is inconsistent, a troubleshooting action may include opening the Apollo unit to access internal water separators.

4.  Blasting Process:

    • Begin blasting at a distance of 12-18 inches from the surface. The further from the surface, the less velocity and thus decreased blast efficiency. Too close is unsafe and also problematic. Experiment on the surface for each job.

    • Maintain a consistent angle and distance to ensure even cleaning.

    • Move the nozzle in a sweeping motion to cover the entire area.

    • It will be obvious when garnet in Apollo runs out (air only is spraying). Refill Apollo as necessary.

5. Monitory Pressure

    • Regularly check the air pressure to maintain optimal blasting performance.

    • Adjust as necessary based on the material and condition of the surface.

    • Use this opportunity to continue clearing water from the water separator on both the compressor and the Apollo unit.

Post-Blasting:

6. Surface Inspection:

    • Inspect the blasted surface for cleanliness and any remaining contaminants.

    • Identify any areas requiring additional attention.

7. Powering Down:

  • Turn off Compressor motor, allow fan to continue to run for cooling. In hot conditions let external air mover continue to run.

  • Red hose will not release until internal pressure dissipates. Use water separator release valve on Apollo to zero out pressure.

8. Cleaning:

  • Begin with push broom sweeping into piles, use snow shovel to transfer to contractor bag. Garnet is heavy, fill bags accordingly.

  • After initial push broom and snow shovel to remove the major materials, use the regular broom and dustpan, the push broom, the leaf blower, and the shop vacuum to complete the area cleanup.

9. Final Inspection:

  • Conduct a thorough inspection of the area to ensure all cleaning objectives are met.

  • Confirm that the surface is ready for any subsequent restoration or sealing processes.

Documentation:

10. Record Keeping:

    • Document the blasting process, including equipment used and any observations.

    • Take before-and-after photos for records and potential insurance claims. Photos to include everyone wearing PPE, equipment used, materials, and action shots.

Conclusion:

This garnet blasting procedure provides a systematic approach to effectively clean surfaces impacted by fire or smoke damage. Proper preparation, execution, and post-blasting cleaning are essential for achieving optimal results while ensuring safety throughout the process.