Affective and thorough surface preparation is essential. Whether embedded steel reinforcement preparation or steel preparation to SA 2.5, or preparing concrete for the application of anti-carbonation coatings or removing coatings from structures in readiness for the application of our protective coatings and chemical resistant liners, good surface preparation quite literally is key to everything we do.
Here at the Gunite Group we offer a number of options, from conventional open abrasive blasting with grit media, to open blasting with water suppression to dust free preparation utilising the sponge media blasting process.
Many environments we work in require dust and noise control to remove materials safely and effectively from the surface of the structure. Many steel structures within the UK where historically coated with lead base products and safely removing, collecting, and disposing of contaminated waste is a legal requirement and should be considered when undertaking abrasive blasting surface preparation.
The removal of such products is made more difficult when the working environment is restricted such as working within a designated confined space and or working near or above water.
Gunite’s preferred method of removing and collecting such products is utilising sponge media for surface preparation.
Sponge media is poured into the Blast Feed Unit, fed into a rotating stator at the bottom of the pot. The stator moves the sponge media into the air pathway It then passes through a blast nozzle to impact the work surface at 15 to 100 metres (50 to 325 ft) per second, depending on the blasting pressure.
On impact with the surface the sponge particles compress and the bound media grabs and entraps the material being removed (lead paint for example) the media loses its velocity almost immediately and simply falls to ground. This provides a safer less aggressive working environment and importantly a dust free blast, compared to conventional open grit blasting.
The sponge media is collected and put through an air driven recycling unit that separates the surface materials from the sponge media. The recycling unit is a vibrating unit with a series of mesh filters that separates the sponge media from the contaminants.
The contaminated material separates to one side of the unit making separation and collection of the contaminated materials possible. The waste products can be effectively bagged for safe disposal and the sponge media reused up to 5 times or mixed with clean media to formulate a working mix.
This type of surface preparation is ideal for internal and confined space blasting. It is also used for the safe removal of lead- based paint from structural steel members and working in and around the water course.
