Design and Construction of a Locally Fabricated Portable Air Compressor System with Integrated Spray Gun and Abrasive Blasting Capability

This study presents the design and construction of a compact, locally fabricated air compressor system with integrated spray gun and abrasive blasting functionality, aimed at meeting the needs of small-scale industrial, automotive, and domestic applications. The unit features a cylindrical air tank with hemispherical ends, providing a storage volume of 0.03206 m³ (approximately 32.1 litres). The compressor operates with a swept volume of 1.374 × 10⁻⁴ m³ per stroke and an output of 0.206 m³/min (206 L/min). A motor rated at 750 W (1 HP) was selected to meet the required power of 53.3 W, ensuring efficiency and longevity. Efficiency analysis yielded a mechanical efficiency of 81.4%, volumetric efficiency of 82.5%, and overall system efficiency of 73.67%. The spray gun, with a 0.35 mm nozzle, accommodates a pressure drop of 0.84 bar and achieves a throat velocity of 571.5 m/s, while the Venturi design optimizes abrasive delivery. The abrasive blasting system delivers 12.1 kg/min of media, supported by a 16-litre hopper that allows approximately 1.4 minutes of operation per refill. The support frame, designed using 20×20×2 mm angle iron, supports a total system load of 380.2 N, distributed evenly at 95.05 N per leg. A 12V DC pump, rated at 378.6 W and drawing 31.55 A, suggests a battery capacity above 35 A for optimal runtime. The system achieves a required airflow of 2.67 CFM, well-aligned with a 3 CFM pump for continuous use. The final product meets design expectations, offering a low-cost, efficient solution for localized workshop operations.