Sand blasting vs shot blasting: which do you need?

Sand blasting and shot blasting are both abrasive blast cleaning: a stream of media fired at a surface to strip paint, rust and grime. "Shot blasting" usually means heavy steel shot or grit on steel and cast iron. "Sand blasting" usually means a finer media fired by compressed air, gentle enough for timber, brick and stone.

Because the idea is the same, the two names often get swapped around. What really changes from job to job is the media, the air pressure and how the nozzle is worked. Get those right and one process can strip mill scale from structural steel or lift soot from a brick fireplace.

What is the difference between sand blasting and shot blasting?

Mostly, it comes down to what's being fired and how hard it lands:

• Steel shot is small, round and heavy. It hammers the surface clean and leaves a finely dimpled texture.
• Steel grit is angular. It cuts as well as cleans, leaving a sharper texture for primer and paint to key into.
• Finer mineral and glass abrasives are much lighter. Used at lower pressure, they lift coatings and dirt without digging into softer materials.

Shot and grit are the heavy hitters for steel and cast iron, while the finer abrasives are what most people now mean by sand blasting.

Why is it called sand blasting if there's no sand?

The name dates from the days when silica sand was the usual abrasive. Breathing the fine dust that silica sand breaks down into can cause silicosis, a serious lung disease, so it has long since been replaced by safer abrasives such as crushed glass, garnet and aluminium oxide. The old name has simply stuck.

What about aluminium, thin sheet and galvanised steel?

A few materials need special handling:

• Aluminium is soft, and steel media can leave tiny particles behind that later stain and corrode. It gets a non-ferrous abrasive at lower pressure.
• Thin sheet steel, such as car body panels, can stretch and warp if it's blasted too hard. Heavier parts such as chassis rails, wheels and suspension arms cope with much more. See chassis, wheels and parts.
• Galvanised steel can be given a light sweep blast, enough to key the surface for paint or powder without stripping the zinc. Mention that it's galvanised when you get in touch.

Do you have to bring it to the yard?

No. Anything that can travel can come to our yard at Needwood, where it's blasted and coated on the same site. Anything that can't move, from a beamed ceiling to a silo or a crusher on a quarry floor, can be blasted where it is. Our mobile teams work across Staffordshire, Derbyshire and Leicestershire and travel throughout the UK, including the Channel Islands. The team is SPA and IPAF trained, Belmont is Avetta registered, and every site job comes with risk assessments and method statements.

Which is cheaper, sand blasting or shot blasting?

Neither is cheaper as a rule. What sets the price is how big the item is, what condition it's in and how it will be finished. Heavy, flaking paint takes longer to strip than a light bloom of rust, and ornate scrollwork takes longer than a plain frame. For a free quote, WhatsApp us a photo with rough sizes. We can price most jobs from photos alone.

Sand blasting and shot blasting near Burton upon Trent

We've been blasting from Belmont Farm at Needwood since 2001, close to both the A38 and the A50, and we work for customers all over Staffordshire, Derbyshire and Leicestershire. To talk a job through, call 01283 813528.