Grit blasting cleaning

Glass bead blasting (cleaning) Grit blasting using glass beads. See also Shard. 

Sprayed coatings These are of the greatest importance, particularly for the protection of structural steel or certain aluminium alloys. The metal to be coated must be grit blasted shortly before spraying to provide a clean rough surface. Chilled iron grit is used for most steelwork, while alumina or silicon... 

All metal surfaces such as mild steel should be grit blasted, normally to SA 2-5 as defined in Swedish Standard SIS 055900. If the surfaces are contaminated with oil, grease or a chemical from previously used items, the contamination is usually removed by sweating in steam prior to grit blasting. Concrete surfaces must be clean and dry and any laitence must be removed as it will affect the bond of the lining. Preferably the surface should be grit blasted. 

Surface preparations must be carefully controlled for reliable production of adhesive-bonded parts. If a chemical surface treatment is required, the process must be monitored for proper sequence, bath temperature, solution concentration, and contaminants. If sand or grit blasting is employed, the abrasive must be changed regularly. An adequate supply of clean wiping cloths for solvent cleaning is also mandatory. Checks should be made to determine if cleaning cloths or solvent containers have become contaminated. 

Pretreatment of the substrate for plasma spraying consists only of cleaning and mild grit-blasting. If the bulk substrate is not capable of withstanding the temperatures involved, it may be necessary to apply a film of a metal such as nickel or molybdenum to provide a stable substrate. Plasma spraying has not been widely used, and for many applications has probably been superseded by sputtering. 

Before the application of the adhesive, the bonding surfaces have to be prepared. To clean the surfaces properly, the aluminum of the chassis is grit-blasted (corundum 20-30 pm grit) and the GRP of the cabin is ground with a very fine grinding pad. Then, any dirt and dust particles are removed with the Sika Cleaner-205 and brushed with a suitable Sika Primer. Then the cabin is set onto the chassis in the correct position using polyurethane distance holders to control the adhesive thickness, before Sikaflex -254 Booster is injected into the joint with the booster pump equipment, pressed, and skinned into the joint with a spatula. A small gap with a depth of 5 mm has to remain later, this gap is filled with Sikaflex -265 to achieve a durable seal. 

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