The team at SBL have a number of blast cleaning methods and media at our disposal. There’s the usual suspects of course – soda crystals, crushed glass, and vapour blasting (sometimes called “aqua blasting”). And we also use a handful of less common blast media when the project requires it, such as aluminium oxide, crushed garnet, and crushed olivine. We also offer ThermaTech® steam cleaning too.
But there are two procedures that we simply don’t do – shot blasting and sand blasting – though we do get asked about them from time to time. So let’s explore these two blast cleaning methods in depth and look at why we focus our efforts elsewhere.
What is Shot Blasting?
Shot blasting works much like any other kind of abrasive cleaning procedure: small particles (called “blast media” – in this case small steel ball bearings) are pelted at the surface being cleaned. An air compressor projects the ball bearings onto the surface at high velocity; the friction caused by this impact makes any unwanted coatings or dirt come away.
Some people use the term “shot blasting” as a general term for blast cleaning, but it’s actually a specific term that refers to blast cleaning with ball bearings.
Shot Blasting Benefits
Shot blasting provides a really abrasive clean, so it generally gets used a lot within heavy industry. Thick steel lintels and large industrial components are generally a good match for shot blasting, especially when they need an especially thorough clean.
There are two main ways of carrying out shot blasting – using handheld blasting equipment or using a fully automated conveyor belt. Both ways have their own benefits. Handheld cleaning means that an operative can take the requisite care of the item and can focus on areas that need particular attention. Automated cleaning on a conveyor belt would (in theory) create a more uniform finish because each area is blasted for the same amount of time.
Shot Blasting Drawbacks
As stated above, shot blasting is a powerfully abrasive media and can easily damage many surfaces. The impact of the ball bearings generates a lot of friction, so the resulting heat makes it unsuitable for surfaces that are susceptible to heat warping, such as vehicle panels and shells. The impact can easily take faces off hard-faced brickwork too.
Shot should only really be used when absolutely necessary. It can be so potentially destructive that if you’re in any doubt, cleaning a test patch may not be advisable.
Why We Don’t Shot Blast
Though it undoubtedly has its uses, the destructive nature of shot blasting makes it largely unsuitable for the kind of work we carry out. We specialise in blast cleaning for vehicles, building restoration, and engineering; many of these cleans require a far gentler approach than shot can provide.
Shot blasting is also rather expensive to us as cleaning providers. Though the ball bearings themselves can be reused around 25 to 50 times, the purchase and running costs of shot filtration systems can be very high. So high that we wouldn’t be comfortable passing this cost on to our customers.
What We’d Probably Do Instead
We decide the best course of action for each project on a case-by-case basis, but when a particularly abrasive clean is needed we will generally opt for crushed glass, crushed olivine, or aluminium oxide.
Though we have a good selection of blast media types at our disposal, there are occasions where none of them are the right choice for the particular task at hand. In this case, we will discuss other options with the customer and advise on next steps.
What is Sand Blasting?
The process of sand blasting is exactly the same as our other abrasive cleaning methods, except it uses coarse builder’s sand as the blast media. Operators would use an air compressor to blast sand at a surface in order to remove dirt or unwanted finishes. We say “would” because using sand for blast cleaning is now illegal in the UK.
Why Is Sand Blasting Illegal?
It’s now illegal to blast clean with any media that contains sand or silica, thanks to the Control of Substances Hazardous to Health Regulations 1999, known as COSHH. Using sand or silica-based materials as blast media throws imperceptibly small respirable crystalline silica (RCS) particles into the air. When breathed in, these particles can stay in the lungs for many years. Long-term exposure to RCS can result in debilitating lung conditions, most notably silicosis and COPD (chronic obstructive pulmonary disease).
Why Do People Still Use the Term “Sand Blasting”?
Because old habits die hard! Sand blasting has been a common abrasive cleaning method in the past, and many people aren’t aware that sand blasting is now illegal. Blast media like crushed glass and soda crystals do look a lot like sand, so that doesn’t help either!
Why We Don’t Sand Blast
SBL don’t use sand because it’s illegal and potentially hazardous – simple as that. The risks wouldn’t just be borne by our staff, there’s a possibility that we could endanger neighbours and nearby pedestrians too.
What We’d Probably Do Instead
Crushed glass remains a strong contender in the blast cleaning stakes for a number of uses – it’s what replaced sand blasting after all. Crushed glass is incredibly versatile; we can turn the pressure up or down on our air compressor to accommodate the strength of the clean required. Alternatively if an extra gentle clean is needed, we’ll use our namesake – soda!
Our team are reliable blast cleaning partners to diverse clients across the West Midlands and beyond. So if you’re considering the services of a blast cleaner, give us a call today on 0800 774 7632 for an informal chat.