Bead Blasting a Cast Iron Sink
Bead blasting is the process in which tiny beads are used to remove corrosion and dirt from metal. The beads are propelled at high pressure through bead blasting equipment. The process is called peening and it also helps prevent corrosion. The beads are similar in size to sand and are available in different gradients. If the cast iron sink is coated with porcelain or enamel, it needs to be removed before you can peen the cast iron itself. The coating can also be removed using the bead blasting technique.
Step 1 – Select Glass Beads Appropriate for the Job
Glass beads are available in various sizes. Bigger beads are usually used for bead blasting cast iron. The details of bead sizes that your equipment uses can be found in the owner’s manual. There is other blasting media such as walnut shells and metal, but glass is used for this project.
Step 2 – Understanding the Parts of the Bead Blasting Equipment
Bead blasting equipment comes in a multitude of sizes, from dresser size to room size. No matter what the size, the machines involve the same general parts. There is a chamber where the item to be cleaned goes into and where the actually blasting takes place, pressurized air, a media (bead) container, and a media collector. Smaller equipment often has blasting jets that are manually manipulated. The operator puts their hands into rubber gloves attached to a chamber with a glass viewing area (something like an infant incubator).
The item to be blasted is placed in the chamber and closed off. The machine is started and the jets propel the media at the item and remove the corrosion. The used media is collected in the reclamation chamber.
Step 3 – Setting the Air Pressure
The normal air pressure used for bead blasting cast iron is 80 psi. You can set the air pressure at a lower psi at first and then gradually raise it to reach 80 psi.
Step 4 – Selecting the Blasting Media
The normal size of beads used for bead blasting a cast iron sink is Size 4. They are categorized as 30 to 40-mesh glass beads. Always buy good quality blasting media. It should also be kept dry.
Step 5 – Determining the Gun Angle and Distance
The blasting gun should be held at a 45 to 60 degree angle. Do not hold the gun at 90 degrees because this will slow down the blasting action and will cause gun damage. Also, hold the gun 6 inches away from the part of the cast iron sink being peened.
Step 6 – Bead Blasting the Sink
Be sure to wear all the safety gear. Close the cabinet doors. Turn the power on and hold the gun at least 6 inches away from the surface to be bead blasted. Now, switch on the equipment and the beads will start propelling through the gun. Continue bead blasting the sink until all rust is removed and the desired finish is reached.