See how many pounds fit in your pot, how fast it empties at your nozzle size, and how many refills you need for the job.
Quick answer
Results are estimates based on industry-published bulk density and flow data. Actual rates depend on metering valve setting, media condition, and hose configuration.
Your company name and logo go on the document. Stays in your browser. Never uploaded.
A blast pot (also called a pressure vessel or blast machine) is the pressurized container that feeds abrasive media into the air stream. Pot size directly affects how long you can blast before stopping to refill, which determines your productivity on the job.
The capacity of a blast pot in pounds depends on two factors: the internal volume (measured in cubic feet) and the bulk density of your chosen media. Coal slag at 80 lbs/cu ft fills a 6.5 cu ft pot to about 520 lbs, while garnet at 145 lbs/cu ft fills the same pot to 940 lbs. This weight difference matters for trailer loading and daily media logistics.
For most field work, a 6.5 cu ft pot is the standard. It balances capacity against portability and fits on a standard single-axle trailer alongside a compressor. Larger pots (12 or 20 cu ft) make sense for shipyard or industrial plant work where you blast continuously for hours. Smaller portable pots (0.5 to 2 cu ft) are used for touch-up, detail work, or confined spaces where a full rig cannot reach.
On large jobs, plan media delivery based on pot loads per day. A blaster running a #6 nozzle at 100 PSI with coal slag burns through about 46 lbs/min, emptying a 6.5 cu ft pot every 11 minutes. Over an 8-hour day with 80% uptime, that is roughly 35 pot loads or 18,000 lbs of media. For a week-long job, you need planning for 90,000+ lbs of media delivery, storage, and spent media removal.
Every refill cycle costs 3 to 7 minutes of downtime depending on your setup (gravity fill vs. pneumatic fill, hopper proximity, single vs. dual pot). On a job requiring 30 pot loads, refill downtime adds 2 to 3.5 hours to your day. Dual-pot setups eliminate this by letting one pot pressurize while the other blasts, but require more capital and a larger compressor.
Depends on pot size and media density. A standard 6.5 cu ft pot holds about 520 lbs of coal slag or 940 lbs of garnet. Multiply bulk density (lbs per cubic foot) by pot volume in cubic feet. Lighter media like walnut shell only fills to about 290 lbs in the same pot.
With a #6 nozzle at 100 PSI, a 6.5 cu ft pot of coal slag lasts about 11 minutes. Heavier media and larger nozzles empty the pot faster. A #8 nozzle at the same pressure burns through the same pot in about 5 minutes. Use this calculator to get exact times for your specific setup.
Divide total media needed by pounds per pot load. Total media = surface area (sqft) times consumption rate (lbs/sqft). Example: 1000 sqft of heavy coating with coal slag needs about 12,000 lbs, or roughly 23 pot loads in a 6.5 cu ft pot. Enter surface area above for automatic calculation.
Depends on media type and coating condition. Coal slag uses 5-17 lbs/sqft (light to lead paint). Garnet uses 1.5-4.5 lbs/sqft. Steel grit uses 0.2-0.8 lbs/sqft because it is recyclable. Heavier coatings require more passes and more media per square foot.
Multiply your nozzle CFM by the media-to-air ratio for your media type. A #6 nozzle at 100 PSI flows about 232 CFM. Standard media (slag, glass) flows at roughly 0.20 lbs per CFM, giving about 46 lbs/min through the nozzle. Heavy media (garnet, steel grit) flows at 0.25 lbs per CFM.
Related tools