Metal blasting: which is the best?

metal blasting

What is metal blasting and what is the best

We often hear about metal blasting but, often, it is easy to get confused. Let’s provide some clarity. First it is necessary to understand in detail what it is. Industrial sandblasting is the most valuable method of preparing metal surfaces before starting to paint a surface or applying a protective layer against corrosion. It is therefore an application of sandblasting technology, which scrapes surfaces and does so with a jet of sand. The metal surface must have certain characteristics to be able to provide a suitable base for protective coatings. It therefore needs to be cleaned of anything foreign to its metallic nature. This is in addition to traces of old paint and other foreign substances that undermine the effectiveness of the protective system because they create intermediate layers between the actual metal and the rustproofing film. Let us now see what the main types of sandblasting are.

Table of contents:

  1. conventional sandblasting
  2. closed-loop or suction sandblasting

Wet sandblasting

This type of blasting is different from dry blasting in that water or a solution of water and corrosion inhibitor is introduced into the abrasive stream. Special advantage: it reduces the formation of dust that occurs in blasting operations. It is recommended when blasting cannot be done outdoors or in a blasting booth. It is not suitable for all situations. In fact, in metal structures that have a large number of horizontal beam recesses, cleaning operations are difficult if they are done wet. This is because it is very challenging to remove wet sand and other residues from the process. Another shortcoming is its slowness compared to dry cleaning since the presence of water reduces the abrasive capacity of the material used. This affects production costs.

Dry sandblasting

The most commonly used dry blasting methods in metal structure assembly fall into two basic types:

  • conventional or open-cycle
  • suction or closed-cycle

Conventional blasting

Conventional or open blasting is a method that is used in which there are no arrangements for decreasing the hazards involved in dust production or even for recovering the abrasive material.

Closed-loop or suction sandblasting

In the suction blasting process there is both dust removal and recovery of abrasive material.
The equipment used consists of:

  • double chamber automatic blasting machine 
  • dust collector
  • suction pump
  • special blasting nozzles or lances

The air compressor for the blasting process can be supplied separately. With any type of abrasive, ground cast iron granules are usually used given their higher breaking strength. 
The sandblasting process consists of moving the granules by compressed air. These are then ejected from the machine with a nozzle in recovering by suction the granules after they have worked, and the dust that has been produced through a hollow cone surrounding the nozzle. 
All dust recovery and separation operations work automatically.
The granules are used until they lose their abrasive functions.

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