Beginners’ Guide to Glass Media Blasting

Whether you’re a classic vehicle restorer, a private vehicle collector/enthusiast, or even an estate management professional, there’s a chance you’ll require glass media blasting at some point. It’s our most commonly used cleaning method after all!

So how does it work? How is it different to using other blast media? Let’s investigate.

What is glass media blasting?

Glass media blasting is a method of blast cleaning that uses rough crushed glass media. Compressed air is used to pelt a surface with crushed glass particles, causing any undesirable finishes to come away.

In our experience, glass media blasting is the closest we have to an “all rounder” abrasive cleaning method. It can be used fairly widely across all kinds of vehicle and building restoration projects.

How does glass media blasting work?

Coarse crushed glass particles are loaded into equipment that feeds alongside our air compressor’s nozzle. This allows us to propel the glass particles at a surface at incredibly high speeds. The resulting high velocity of the particles – paired with their gritty finish – causes intense friction which scrubs away any paint or coatings.

Though the practice of glass blasting and soda blasting may appear pretty much identical, they actually produce two very different finishes. Bicarbonate of soda crystals are incredibly soft, so they impact the surface just enough to remove the coating without affecting the substrate underneath. This is chiefly due to the fact that the soda crystals themselves break apart upon impact.

Crushed glass media however doesn’t break apart during the cleaning process, therefore providing a more abrasive clean. Glass blasting is so abrasive that when cleaning hardwoods it can strip away a small layer of the surface. This might sound bad but it actually leaves a rustic, “raised grain” effect that many clients appreciate.

What are the pros and cons of using glass compared to other media?

Glass blasting provides one of our most powerful cleans, so it makes light work of a number of finishes. Glass media is an inexpensive, recycled product that can be disposed of without any special treatment. It also has the potential to create the aforementioned grain effect on hardwoods.

It’s remarkably easy to control the level of abrasiveness – we can turn the air pressure up or down as necessary. Despite our company name, we actually have the most experience in working with glass blasting!

However, glass does have one major drawback. Because it’s such an aggressive media, the sheer amount of resulting friction can cause heat damage and warping when used on heat-sensitive surfaces.

What kinds of items generally require glass blasting?

In terms of vehicle restoration, we generally use glass media to clean away paint, filler, underseal, and rust; though the decision whether to use glass or not may be influenced by the type of component and the material it’s made of.

For building restoration, we use glass blasting to clean paint and graffiti from hard-faced bricks. We also use glass to clean varnish, paint, or graffiti from wooden beams. Because the raised grain finish makes hardwoods appear aged, we’re sometimes asked to blast new beams which have been installed alongside older ones so they appear to match.

So put simply, we may consider using glass media blasting whenever a surface isn’t susceptible to heat damage.

Are there any specific surfaces where glass media blasting should never be used?

Aluminium, carbon fibre, and fibreglass are all susceptible to heat warping, so using glass media to clean them may well distort them. We sometimes also avoid using glass blasting on components that comprise of thin sheet metal such as car bonnets and roofs as they may similarly distort with heat, depending on thickness and material.

Are there any projects that you can say with 100% certainty that you’ll use glass media?

Not really. There are times where we know from experience that glass would be the most likely candidate, but because glass blasting is so abrasive we like to clean a test patch before we commit to any particular method.

When working an on-site project, how do you stop glass particles from spreading around a premises?

Regardless of the blast media being used, we employ a number of extraction processes wherever needed or requested.

For indoor projects, we use dust sheets, plastic sheeting and seal off doors and windows to keep spent media from spreading to other areas. We also use our infamous “giant sock”, a 6 metre long fabric bag that attaches to our extractor fan. The fan sucks in the spent blast media and traps it within the sock.

Outdoors, we can control the spread of spent dust through the air using a “water shroud”. We affix equipment around the blasting nozzle that expels a fine mist of water. This wets the dust, causing it to fall to the ground after impact rather than blowing away. Understandably, we can’t use the water shroud method when cleaning wood or metal.

We can also use methods like “tenting off” areas we’re working on – even on scaffolding. Before embarking on an on-site job, we will talk through all of the practicalities concerning control and extraction of spent media with the client.

Are there any environmental concerns when using glass blast cleaning?

Not really – glass dust isn’t known to be hazardous to wildlife or to the environment. However, it can be unpleasant if left to blow around outside, so we will always clean it up to the best of our ability.

What can I expect when working with SBL?

When you place an enquiry with us, we’ll talk at length about the work that needs to be carried out. We may well ask for photographs to be sent over to help us to establish the scope of the project.

Before we quote, we generally like to inspect any surfaces up close. For vehicles and smaller components that can be transported to our facility, we may ask you to send the item in for inspection before we agree to timescales and costings. For on-site projects, we usually arrange a site visit at a mutually agreeable time so we can similarly confirm timings and cost. At this stage, we may clean a test patch to gauge the work involved and decide on the best method to use. Unfortunately we don’t have any kind of fixed “price list” as two projects are rarely the same!

Once the work is complete, we will check the area/item over thoroughly and ensure that it is left/returned to you clean and tidy. Wherever we are in the process, we’re happy to answer any questions you may have, no matter how small they may seem.

For a more in-depth look at the practicalities of blast cleaning, check out our recent Deep Dive into the Practicalities of Blast Cleaning.

So if you’ve got a surface in need of a thoroughly abrasive clean, give us a call! SBL are trusted blast cleaning partners to numerous individuals and businesses throughout the West Midlands and beyond. So give us a call today on 0800 774 7632 for a friendly chat about your next project.