CZYSTA BLACHA
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CLEAN METAL SHEET




Thorough stripping of old finishing coats from bodywork and chassis components is key in vehicle renovation processes. There are currently several options and technologies available for removing old coatings. Selected examples are listed below, including their advantages and disadvantages:

  • Sand blasting: the name can be misleading, as it suggests that sand is the only abrasive medium available. Of course, many “sand” blasting processors still use sand. However, the process has seen many advancements over the years. The most popular abrasive blasting media now include corundum (aluminium oxide), core smelting slag, and... nut shells. Each abrasive medium has its unique abrasive strength and effectiveness profile. If the abrasive medium is poorly selected or applied, it can deform the bodywork. This type of process is most recommended for confined locations and edges. It is not advised to “sand” blast the panelwork itself, unless using a more recently developed medium, such as a synthetic abrasive like plastic grit. Plastic grit in the form of fine balls carries a low risk of bodywork damage, while maintaining a very high level of coat stripping performance.
  • Glass bead peening: a less invasive abrasive blasting medium, which is excellent for stripping coats from small workpieces and whole assemblies. Here the abrasive takes the form of fine beads of glass, which can be used to gently remove decorative finish coats.
  • Soda blasting: this is one of the latest abrasive processes, and is growing in popularity. The abrasive is based on soda and its derivative compounds. While it is very mild for the base material, it has a low efficiency in stripping hard coatings, meaning that reprocessing may be required. One risk related to this type of processing is the soda residues left on the base material prior to recoating. All soda-blasted surfaces must be thoroughly washed before further renovation processes take place.
  • Chemical stripping: this is the most complex of all coat stripping processes; however, it is the most efficient and the safest for old workpieces. It involves professional stripping chemicals, placed in tanks, into which the workpieces are dipped and bathed. Chemically stripping perfectly cleans the workpieces of old coatings and, once the chemicals have been neutralized, leaves the workpiece surfaces as ideal bases for the following renovation processes.
  • Pyrolysis: a process well known in other industries, and involves the stripping of old coats at high temperatures. A vehicle so processed requires the removal of all synthetic and plastic parts, prior to being moved to a pyrolytic stripping oven. Here it is kept at very high temperatures, but under the steel deformation point.
  • Mechanical or power stripping: this is the most common removal method for old coats. While it is the most time intensive of the processes listed here, it provides the best control over the stripping process. The coats are removed using power strippers, and abrasive paper and plastic pads. Once a surface is stripped of the old coats, any corrosion of the bare metal will be exposed. In most cases, power stripping removes rust from steel. Depending on the corrosion severity, a part of or the entire workpiece may require replacement. If the corrosion sites are relatively small and localized, a corrosion converting agent can be applied. For NfCC, commercial products by the German FERTAN brand are recommended for rust conversion. See detailed instructions for use on the FERTAN website (www.fertan.pl)

 

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