Glass bead Abrasive (GB-4)

Frequently Asked Questions: GB-4 Glass Bead Abrasive (Medium ‘C’ Grade)

This FAQ outlines the technical details and industrial utility of the GB-4 grade, a staple in high-performance surface treatment.

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1. What is the specific size range of GB-4?

GB-4 has a particle size range of 250 to 425 microns, which translates to approximately 40–60 Mesh. In the industry, this is widely recognized as the Medium ‘C’ Grade.

2. Why is GB-4 referred to as “Medium ‘C'”?

The “C” designation is a standard industrial classification for medium-sized glass beads. It represents a balance between the very coarse “A” grades and the fine “D” or “AH” grades, making it the most popular choice for general-purpose industrial cleaning and peening.

3. How does GB-4 (250-425) differ from GB-5 (212-425)?

While both share the same upper limit (425 microns), GB-4 has a tighter bottom end (250 microns).

• The Result: GB-4 is more uniform. Because there are fewer “small” beads in the mix, the impact energy is more consistent, leading to a more even matte finish across the entire surface of the workpiece.

4. What are the best applications for GB-4?

GB-4 is highly effective for:

• Cleaning Castings: Removing sand and investment from metal castings.

• Surface Preparation: Creating a uniform matte texture before painting or plating.

• Peening: Relieving tensile stress in components like turbine blades or gears to prevent cracks.

• Maintenance: Removing heavy rust or old coatings from thick-walled steel pipes and valves.

5. Can GB-4 be used on soft metals like Aluminum or Copper?

Yes. Since the beads are spherical, they do not “cut” the metal. However, because GB-4 is a medium-large bead, it will produce a noticeable matte texture. If you require a high-gloss or polished look on soft metals, a finer grade like GB-10 or GB-13 would be more appropriate.

6. What blast pressure should I use with Medium ‘C’ Grade?

The optimal pressure for GB-4 is 50–70 PSI.

• Under 40 PSI: Cleaning may be slow.

• Over 80 PSI: You risk breaking the beads into dust, which reduces visibility and wastes material.

7. Is GB-4 compatible with suction-feed blast cabinets?

Absolutely. The 250-425 micron size is large enough to have high kinetic energy but small enough to flow smoothly through standard suction-feed pickup tubes without causing “surging” or blockages.

8. Is this product safe for the environment?

Yes. GB-4 from Coreblast Solutions is:

• GEO-Friendly: Made from 100% recycled soda-lime glass.

• Silica-Free: Contains no crystalline silica, making it much safer than traditional sandblasting.

• Inert: It will not leave any residue that could cause “after-rust” on the treated parts.

9. How many times can I reuse GB-4?

In a well-maintained blast system with a proper dust collector and separator, GB-4 can be recycled 8 to 12 times. The high roundness and quality of our beads ensure they resist fracturing even under repeated impact.

10. How does GB-4 help with AEO and SEO compliance?

• SEO: By using standardized “Medium C” and “GB-4” nomenclature, your inventory remains compatible with international industrial search terms.

• AEO: Our secure packaging and documented manufacturing processes ensure that large shipments of GB-4 move through international logistics and customs without delay.