Views: 0 Author: SGA Blasting Publish Time: 2026-09-18 Origin: SEPPE Garnet Team
As discussed in the FHWA Field Manual for Bridge Painting Inspection, blast cleaning is an expensive and time-consuming part of repainting work. The manual also notes that inadequate blasting pressure slows production and that excessive hose length can reduce blasting efficiency. These factors show why blasting efficiency directly affects project-level costs.
DNV’s article on corrosion in cargo and water ballast tanks cites DNV-CG-0288, which sets out methods, technical requirements, principles, and acceptance criteria for the corrosion protection of ships. In practical shipyard surface preparation, these requirements support evaluating overall cost not only by abrasive procurement cost, but also by nozzle blasting productivity per unit time and the waste-handling load per square metre.
This implies that the unit price of the abrasive is rarely the deciding factor in the total project cost.
Instead, blasting efficiency and abrasive consumption rates are the core factors determining expenses related to labor, equipment energy consumption, and waste disposal.
Calculating the total cost of surface preparation requires a comprehensive assessment of material loss throughout the abrasive’s lifecycle—from initial use to becoming waste—including the breakdown rate, cleaning efficiency, and total volume of waste generated per square metre.
In the article Garnet vs. Aluminum Oxide for Blasting, we discussed that for open-air blasting in shipyards, garnet is the more economical choice based on overall performance—offering controllable efficiency, minimal nozzle wear, reduced rework, and a lighter dust cleanup burden, alongside a controllable particle breakdown rate and stable cleaning performance.
A note on garnet recycling: while garnet can be recovered in enclosed blasting environments, recovery and processing costs can be prohibitively high for open-air dockside blasting, where the abrasive becomes contaminated with rust, paint flakes, and salts.
Excessive abrasive breakdown increases consumption; furthermore, large amounts of fine dust can contaminate the surface. This may necessitate rework, secondary blasting, or even work stoppages, thereby driving up total surface preparation costs. This reinforces the earlier point about the need to evaluate material loss throughout the abrasive’s lifecycle when calculating total costs.
Finally, proper moisture-proof storage for garnet is essential; clumping caused by moisture can lead to unstable abrasive feed and interrupt blasting operations.
In addition to selecting the right abrasive, it is essential to match the air compressor pressure, use high-quality nozzles, control the stand-off distance and blast angle, and replace nozzles promptly when worn.
Key operational parameters to monitor include:
Air Pressure
Nozzle Condition
Stand-off Distance
Blast Angle
Removing heavy loose rust and large flakes of old paint from the steel surface prior to blasting can reduce the impact load on the abrasive.
On the job site, low abrasive consumption does not necessarily equate to high overall efficiency.
For example:
| Option | Area Treated | Abrasive Used | Time Required | Result |
|---|---|---|---|---|
| Option A | 100 m² | 100 kg | 10 hours | Extremely slow processing |
| Option B | 100 m² | 130 kg | 5 hours | Strong cutting power and superior surface quality |
When labor costs, air compressor fuel or electricity consumption, and equipment rental fees are factored in, the total cost of Option B is often significantly lower than that of Option A.
To effectively control total costs in sandblasting projects, the key lies in selecting the right abrasive—one that offers consistent cleaning efficiency and controllable consumption rates, thereby minimizing fluctuations in labor hours and reducing waste disposal costs.
SGA alluvial garnet consists of natural, sand-like grains formed by long-term water erosion. It features a stable particle size distribution, low impurity levels, and high resistance to fracturing, all ensured through strict production quality control. If you have a sandblasting project, please contact SEPPE to request samples for testing.
