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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. 

Product nameProduct CodeParticle size
SUPERFINE VCG0425 0.15-0.5mm
FINE VCG7020 0.5-1.0mm
MEDIUM VCG1575 1.0-1.7mm
COARSE VCG3015BB 1.7-3.35mm

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.

DescriptionProduct codesSize in micronsCharacteristics
Crushed Glass "Medium" VCG1575 1000-1700 Large angular grains good for removing coatings and leaving a 'keyed' matte finish
Crushed Glass "Fine" VCG7020 500-1000 Angular, sharp grains good for coating removal and a matte finish
B Glass Bead VS25B 420-590 Large bead gives a slight “grainy” finish compared with those below but the large mass means quick output and a more pronounced peening effect.
Aluminium oxide 46 grit AL46 355 Very tough, large angular grit good for removing coatings and a matte finish
Garnet 30/60 GA25C 250-560 Tough sharp grit. Gives a matte finish. Tougher than crushed glass. Not as tough as aluminium oxide
C Glass Bead VS25C 250-420 Commonly used for carbon removal or fast processing. Bigger mass means a nice bright “satin” look and a uniform finish.
Soda VERA25C 210 More easily washed out of areas where standard media may cause issues. Matte finish.
Crushed Glass "superfine" VCG0425 150-500 Gives a matte finish. Less aggressive than the larger sizes.
AB Glass Bead VS25AB 177-297 A great little all-rounder. Gives a brighter finish than C and still has enough mass to remove coatings effectively.
Aluminium Oxide 120 grit AL120 125 Fine angular grit gives a matte finish
AD Glass Bead VS25AD 105-210 A nice fine media. Great for blasting uncoated alloys, aluminium etc. Will remove coatings but not as quickly as its larger counterparts but will give a great “wow factor” finish.
Aluminium Oxide 240 grit AL240 53 Angular grit. Matte finish. Less aggressive than its larger stablemates.
AH Glass Bead VS25AH 44-88 Has much smaller peening effect that the larger beads and less surface change. Gives a nice bright finish. Holding the beads in your hand it almost has a flour consistency. Our wet-blast units are better able to handle media this size than dry units.