Frequently asked questions about blast cleaning

What is blast cleaning?

Blast cleaning is the process of projecting an abrasive material either in a wet state or dry state onto a surface with enough acceleration to prepare the surface. Examples of these materials include glass beads, metal shot, and sand, among others.

Very often, these media, as the abrasive materials are called, are recollected after blast cleaning either to be reused or to be recycled. The type of finish achieved by blast cleaning depends on the abrasive material used.

Blast cleaning serves four different objectives. It can either smoothen a rough surface, make a smooth surface rough, change the surface profile of material or remove contaminants from a surface.

This activity is carried out in blast rooms, specifically designed to contain the fine abrasive materials used for blasting and preventing them from entering the outside atmosphere. There is also a system for dust collection that allows for these particles to either be recycled, reused, or safely disposed of.

Methods for Sandblasting

There are two methods of blast cleaning. The first method is called air blasting. As the name suggests, air blasting uses pressurized air to propel the abrasive media against the surface. Air blasting is great for cleaning surfaces as well as removing rust and scales from metal surfaces. It is also effective on steel substrates for surface preparation as a precursor to applying adhesive coatings.

The second method is known as wheel blasting, and as the name suggests, the main blast equipment in question is centrifugal wheels. In this method, a blast wheel using centrifugal force propels the abrasive media against the surface in question. The media of choice in this method includes stainless steel shot, grit, and cut wire, all of which are recyclable materials.

The size of these shot blasting machines varies in size and in the number of wheels used in the machine based on the materials blasted and the finish expected. 

These machines are more popular because wheel shot blast machines allow for increased production output, allow for more parts, and are capable of more finish requirements. 

What is commercial blast cleaning?

When blast cleaning is done with the primary objective of removing traces of oil stains, mill scale, dust, dirt, rust, oxides, and other contaminants from a surface, leaving behind not more than 33% of the surface stained.

What is sandblast cleaning?

Simply put, sandblasting is the process of air blasting with the addition of a sandblaster to clean a surface. This process uses the abrasive properties of sand applied under high pressure onto a surface. Blast cleaned surfaces undergoing this treatment will be smoother and more even than before.

The process begins with pouring sand into chambers known as blast pots in the sandblasting machine. This machine is connected to an air compressor. When activated, the compressed air propels the sand onto the surface in question through a hand-held nozzle at pressures ranging from 50 to 130 psi (pounds per square inch).

What is white metal blast cleaning?

When a surface is blasted with the purpose of removing all foreign matter such as rust, paint, or mill scale from it and leaving it a dull gray or even white as a precursor to coating it, it is called white metal blast cleaning or brush blast cleaning. The blasting system used could be air blasting or wheel blasting.

What is the difference between SA 2.5 and SA 3?

SA refers to the grade of sandblasting done on a metal surface prior to coating.

Also, SA 2 is when the blasting cleans the surface up to 65%.

SA 2.5 is also referred to as “near white metal clean”. In this case, the blast cleaning ought to have cleared more than 85% of the contaminants on the surface. Only slight spots and stains may remain.

SA 3 is when the surface has been completely cleared of all contaminants, or what is also known as white metal blast cleaning. 

How much does blast cleaning a house cost?

Blast cleaning domestic surfaces can cost between $1,500 and $7,500 for an average American single-family home. The prices vary depending on the media and the desired finish. 

Written by Narayan Shrouthy. April 23, 2022

Narayan is a content writer for Kukun. With experience in both content writing and editing, Narayan mixes his writing and love for reading with his passion for music. As an active musician, He aims to be a key player in Kukun's content experience.