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| Blasting and Coating |
Bead blasting is a type of metal finish that is achieved by firing small glass beads under pressure at the article and thereby removing small imperfections such as casting flaws and burrs. It is also used in conjunction with water for cleaning concrete and stone so has a number of different applications. Unusually for this kind of technique, it is possible to carry out bead blasting on a small scale by buying equipment which is storable (and usable) in the average garage. For anyone who likes to work with metal which then needs an aesthetic finish, this kind of home-size bead blaster is ideal.
Commercial Use:
Huge bead blasting chambers are available from several companies which will take very large pieces. The process is usually available at three different stages, giving different degrees of finish. Even at 1 stage, the lightest blast, the finish is perfect and, unlike mechanical polishing, leaves no folds or minor imperfections. This makes the process ideal for any vessel or piece of equipment used in the medical, veterinary or food production sectors, as there are no nooks and crannies left to harbour germs or debris. The ‘bead’ in this instance is a fine aluminium oxide and gives a matte grey finish. 2 stage bead blasting uses a fine glass bead and the item is passed through twice. This gives a brighter, semi-gloss finish and looks very attractive. It is also smoother than 1 stage items but costs more, using as it does twice as much material. Three stage bead blasting as its name suggests uses three passes and a much finer bead. The finished item has a lovely sheen and the surface is absolutely perfectly smooth, with no imperfections at all. Even with one stage bead blasting there is no acid weeping from joints and also no rust left on the surface, so items last much longer.
Removing Cosmetic Flaws:
In an industrial setting, bead blasting is generally used on stainless steel, aluminium and titanium, especially in the automotive industry. It can also be used for other metals used in jewellery and art installations such as gold, silver, brass and copper. Because the beads are so much softer than the metal being cleaned or prepared, there is no danger of damage being done to the item in the way of deforming it or losing definition so it is an ideal way to clean any corroded metal parts which may be quite delicate. Bead blasting can be either wet or dry – wet bead blasting is gentler than dry and is sometimes referred to as peening. This can be used to clean soft items such as wood and concrete or tile. In this way, dirt and concretions can be removed from buildings and relatively thin metal welds or constructions. One of the side effects of bead blasting is that the surface of the item is actually strengthened by a slight compaction of the surface because of the impact of the beads, making joints stronger and surfaces rather more resilient.
Art and Metal Sculpture
Bead blasting is used extensively by artists who work in metal, either as a welded piece or cast. When pieces of metal are welded together, the weld is the strongest point but is also the least attractive as it is impossible to weld totally invisibly. Some artists use these construction points as a part of their work and deliberately make them visible, but others would rather have them removed. Bead blasting also gives an even finish and the item has a homogeneity that is impossible to achieve any other way except painting, which many artists feel impairs the integrity of the work. Bead blasting equipment is relatively inexpensive and if used wet the beads are easy to clean up afterwards and can even be reused a number of times if washed thoroughly. Any residue that is not collected and recycled can be added to landfill. Because bead blasting can be adjusted for strength and can be used even on soft stone such as sandstone, it is a very popular method for cleaning statues, large areas of stone as may be found in a garden or park or even for blasting wood which is out in all weathers but must keep its strength such as steps. Gentle bead blasting removes slippery algae and moss without weakening the basic structure and so many parks and gardens use bead blasters regularly to keep paving and walkways safe and free from slip hazards. There are few cleaning methods which can be used in huge industrial settings and in an artist’s studio with equally good effect – bead blasting may even turn out to be unique in that respect.
About Author:
John Hinds writes for Lojix. His interests include blogging, reading, playing tennis, listening to music and traveling.
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