Marine Corps Research Blast Booth Productivity
Just last month, the Naval Surface Warfare Center, Carderock Division Public Affairs, reported on its recent partnership with the Marine Corps Corrosion Prevention and Control (CPAC) Program aimed at mitigating the damaging effects of corrosion and extend the useful life of equipment.
In teaming up together, the duo worked to identify and research corrosion repair capabilities within its Corrosion Repair Facilities (CRFs) to make them more effective and efficient while complying with environmental and safety regulations.
According to the report, CRFs are utilized to provide field-level intermediate corrosion mitigation on ground vehicles and tactical support equipment. When making repairs, crews will prepare an equipment’s surface through abrasive blasting, which is then followed by the application of a Chemical Agent Resistant Coating system. For the blasting portion of the multi-step repair process, the Corps note that access to the blast booth is a known process constraint.
To help better manage this issue and assist in developing a timelier repair process, the CPAC program teamed with the Office of the Secretary of Defense to investigate the benefits of using a portable vacuum blast system.
Described as having self-contained blast capabilities, the portable vacuum blast system is able to reclaim blasting materials at the point of application by utilizing shrouds of bristle material, which prevent the blast abrasive from escaping and can be recycled within the system for next available use. The shrouds are reported to come in all types of shapes and sizes in order to allow for different substrate configurations, such as corners and small crevices.
Due to the machine’s ability to prevent loss of abrasive during the blast process and its small amount of material quantity (less than 3 cubic feet), the portable vacuum blast unit is exempt from the air quality regulations that require other types of blasting equipment to require a booth.
Because CRFs perform within a limited space, the ability to not have to utilize a booth for blasting operations can open the door for more repair projects, increasing its capacity and decreasing project timelines.
“During the corrosion repair process, managing production is like a jigsaw puzzle where you’re trying to move an asset out of one place so you can blast it, and move it to another place to paint it,” Materials Engineer Eric Moffatt said.
“With this system, you’re able to keep equipment out of the blast booth and focus on the affected area. This allows efficient production and encourages uninterrupted process flow. Ultimately, this capability can be used on most of the assets that come through a CRF, though it is best suited for small area repairs.”
One major advantage the teams reported on through its research was the ability to target spot repairs. Prior to using a portable vacuum blast unit, crews would have to strip the coating from an entire asset to repair. However, with the portable unit, they can now perform condition-based maintenance when removing coatings.
“The vacuum blast system at II Marine Expeditionary Force (MEF) CRF has been a significant enabler,” II MEF CRF Manager Charles Wolfe said. “During the facility upgrades, in which the blast booth was down for over six weeks, the II MEF CRF used the system extensively. The vacuum blast system allowed II MEF CRF to work on items with localized scaling, flaking, pitting corrosion and areas that would normally require the blast booth. The system significantly mitigated the single point failure of our one and only blast booth.”
In a recent project, the Amphibious Assault Vehicle (AAV) Program Manager approached the CPAC Team for its support of the Common Remotely Operated Weapons Station (CROWS) upgrade for the AAV platform. In using the portable vacuum blast system, crews were reported to have drastically decreased overall labor costs for the AAV CROWS upgrade versus the use of traditional coatings removal tools by decreasing the time required to remove coatings.
From the study, and in additional projects since, the team has found that the use of the portable unit has reduced planned labor hours for a single asset by 62%. To put that into perspective, when multiplied by the total number of proposed implementations, over 8,500 labor hours were avoided—equating to more than four years of time.
“Support of the AAV Program was a unique opportunity to showcase the partnership between the USMC and Carderock and employ a new capability that was versatile and increased productivity,” Moffatt said.
As a result of this study, the portable vacuum blast system has been deployed for use in all CRFs operated by the Marine Corps.
The USMC CPAC program continues to look to effectively implement this technology into its repair processes both at the organization and intermediate maintenance activities. Carderock is currently leading an effort to outfit “on-the-lot” capabilities utilizing the portable vacuum blast system as part of a larger effort for enhanced surface preparation and touch up to help decrease corrosion repair backlog.
Other Blasting Research
In June, the Norfolk Naval Shipyard’s Paint and Blasting Shop (Code 970, Shop 71) in Portsmouth, Virginia, was reported to have received an equipment upgrade. In adopting a Critical Coat Blast Booth, Shop 71 says that it has already noted improvement in energy savings, material costs and reports that the equipment will require fewer working hours to complete various painting and blasting operations.
Reported to be a fully enclosed 7 feet by 8 feet by 14 feet cubic blasting area, the Critical Coat Blast Booth is environmentally controlled using heating, ventilation and air conditioning equipment used to meet surface preparation requirements. This is achieved through the equipment’s use of media to physically blast different metals such as steel or aluminum surfaces.
Due to its rugged design, the blast booth is primarily designed to use aluminum oxide blast media but can blast other types of media as well. Thanks to the equipment’s light efficiency bag-filter house, blast grit light enough to be lifted through the air is filtered out, while also saving energy through its ability of not having to recondition the air.
As for materials heavier than the air, these items then fall through the floor grates and are swept to a reclaim system, which then sifts, strains and separates blast media from undesired items such as dust, bolts, wire-ties and anything too large. This replenishment is accomplished through the addition of new media through the floor sweepers.
To access the booth, users can enter by using a personnel door on the side and fully opening double doors on the end. Code 970 Inside Shops Preservation Zone Manager Tracy Robinson expanded on the booth’s design, stating that the equipment is vital in supporting smaller critically coated jobs, which are described as being components removed from the ship from “critically coated areas” that are not accessible for preservation when the vessel is underway or in service.
In addition, these components are also critical in the sense that once they are exposed to harsh environments, they become very corrosion prone once introduced to a fully submerged area such as a potable water tank, which holds water for the crew’s drinking water and water used for food preparation.