Brief Guide to Garnet Abrasive Conductivity Testing per ASTM D4940

Garnet abrasives are widely used in blasting operations due to their hardness, efficiency, and reusability. However, the presence of moisture or conductive impurities can affect both performance and safety which will reduce the lifetime of coatings.

 

Electrical conductivity testing according to ASTM D4940-15 provides a reliable method to assess purity and suitability of garnet abrasives for critical applications.

 

The main steps are divided into four parts:

 

1. Prepare garnet samples and distilled water in a 1:1 ratio, typically 300 milliliters; 

   Calibrated conductivity meter; 

   Beaker; 

   The stirring rod;

 

2. Stir the mixed garnet and water for one minute; And let it stand for eight minutes, then stir for another minute;

 

3. Filter and stir the liquid before testing；

 

4. The conductivity test value of the garnet sample is obtained by subtracting the distilled water data from the actual data obtained.

 

 

According to the ASTM D4940-15 testing standard, the conductivity value is required to be less than 150us/cm.

High conductivity may indicate moisture, salt, or metallic impurities.

 

Why Test Conductivity?

 

Safety: Conductive abrasives can pose electrical risks in wet blasting environments.

Performance: Moisture or impurities can cause nozzle clogging, reduced efficiency, and poor surface preparation.

Quality Assurance: Ensures compliance with industry standards and project requirements.

 

Conclusion:

ASTM D4940 offers a quick and effective way to evaluate the electrical conductivity of garnet abrasives. Regular testing helps prevent operational issues, ensures operator safety, and maintains blasting quality.