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011 Crushed Glass

Crushed glass and its application in a Dana-Ridge wetblaster

There are many surface finishes available in a Dana-Ridge wetblast machine and so far, we have looked at how to achieve some of them using

  • Glass bead
  • Aluminium Oxide
  • Soda

Now we’ll look at another popular media, crushed glass…

Made from recycled bottle glass and combined with the Dana-Ridge wetblast process, it is an environmentally friendly and cost-effective way to obtain a quality surface finish.

The product is non-reactive/inert and contains less than 1% free silica (silica sand contains up to 99% free silica) which makes it safer for dry blasting and of course even safer in the Dana-Ridge wet process that already has inherent dust-suppressing qualities.

Crushed glass isn’t as hard or durable as aluminium oxide or garnet for example, and the cutting edges of the glass particles will tend become rounded over time as it impacts on the surface. However, it’s still a great media to blast with.

Of course, the wetblast process ensures much longer media life than in a dusty old dry cabinet and significantly less mess/media loss than an open system.

You will get a matte finish from the angular shape of the crushed glass and it is good for removing paint or giving a ‘keyed’ surface for a new coat of paint to stick to.

It comes in a variety of sizes depending on the surface finish that you require. Dana-Ridge supplies four main particle sizes in 20kg bags or in 1-tonne bulk bags.

It even has more surprising applications. These include things such as filtration or combined with paint  to provide a textured grip on walkway surfaces (it is sharp enough to blast with but not sharp enough to cut yourself with). It is also sometimes used as filler as it is inert and environmentally friendly. 

Blasting away powder coat

In our COMET wetblast machine, we blasted a powder-coated piece of gym equipment with various media including glass bead, aluminium oxide and crushed glass. In a future blog we will compare the finishes and processing speeds on that same piece.

In the meantime, you can click on the photos below to see a comparison between a large 46 grit (≈355µ) aluminium oxide and an even larger “fine grade” (500-1000µ) crushed glass. Both sections were blasted with fresh new media at 80psi and took a comparable time (43s for oxide, 47s for crushed glass) to remove the same sized section of powdercoat (105 x 42mm). They both give a matte finish with a good ‘keyed’ surface that a fresh coat of paint will adhere to well. Both oxide and glass are available in much smaller sizes for a finer finishes than those achieved here.

The advantage of the aluminium oxide is that it is much harder/tougher. When the particle does break, it breaks into new cutting surfaces, thus retaining its blasting properties for longer.

Crushed glass has the advantage of being much cheaper and more environmentally friendly in its manufacture and is a very effective media to use in a wetblast unit.

Crushed glass on thin aluminium

For comparison, we also blasted an scrap piece of aluminium flat bar (25 x 0.6mm thick) to show the effect of relatively large crushed glass and aluminium oxide at relatively high pressure (80psi) on softer material. 

Generally customers use glass bead on soft metals like brass and aluminium but if you want a more profiled surface rather than a bright surface then this will achieve it. Click on the photos below to compare.