Blast Off: Choosing The Best Sandblasting Media For Rust Removal

When most of us think of sandblasting, the first thing that springs to mind is probably an operator using a bulky blasting machine to scour large sections of poured concrete; however, while the sandblasting process is disarmingly simple, it is also surprisingly versatile, and with the proper tools and knowledge sandblasting can be used on a much wider selection of materials.

When used on ferrous metals such as steel and wrought iron, a sandblaster can be remarkably effective at removing deposits of rust and corrosion, revealing the undamaged metal beneath while causing minimal structural damage to the metal itself. This process can be undertaken professionally by sandblasting services, or by yourself using a hired sandblasting machine.

However, if you want to get the best results from using sandblasters to remove rust, you should choose a sandblasting media that suits the task in hand. The following sandblasting medias are ideal for removing surface rust from metal objects and components both large and small:

Aluminium oxide

Aluminium oxide is one of the gentlest medias around, and small-scale versions of aluminium oxide blasters are even used by some skin clinics for dermabrasion treatments. Despite this soft touch, however, aluminium oxide is more than capable of removing relatively thin coatings of rust on metal components. Crucially, it does very little damage to the unmarred metal beneath the rust layer, making aluminium oxide an ideal media for blasting thin sheet metal and other relatively fragile metal objects.

Another excellent quality of aluminium oxide is its low prices, and large quantities suitable for extensive sandblasting tasks can be picked up very cheaply. Unfortunately, aluminium oxide is generally too gentle to tackle deeper rust deposits. You should also bear in mind that aluminium oxide is not environmentally friendly, and must be disposed of properly to prevent contamination of surrounding areas and groundwater sources.

Walnut shells

An excellent choice for the environmentally-conscious sandblaster, walnut shells are very inexpensive and readily biodegradeable, but are still hard enough to remove minor coatings of rust on metal objects. Since walnut shells are considerably softer than even the softest metals, they can be blasted at rust deposits are very high speeds without fear of damaging or warping the metal beneath, making them an excellent choice if you wish to remove rust from more delicate metal objects (such as vehicle components).

However, walnut shells will not be able to tackle more entrenched rust deposits, and tend to make a considerable mess during use, although this mess will not contaminated surrounding areas with chemicals. Their uneven, angular shapes may also cause feed problems and blockages when used in smaller sandblasters.

Glass beads

A classic sandblasting media for cleaning concrete, glass beads are equally useful for removing thicker coatings of rust present on metal objects, and are particularly efficient when used on large areas of rust-coated metal, such as rusty metal roofing slats. They are less expensive than some other 'heavy' sandblasting medias, and errant beads can be cleaned up with a dustpan and brush rather than an industrial vacuum.

Glass beads are particularly useful if you wish to coat your metal with paint or powder coatings once the rust is removed. This is because the hard beans dent the metal beneath slightly, creating an uneven surface which allows paints and coatings to bond closely to the metal. However, this denting causes unavoidable damage to the metal's structural integrity, and glass beads are often too harsh for use on delicate metal components.