No matter how thick and good the paint is, unfortunately, it does not last forever. The external painting of your house, the paint on your car or boat, or the steel underneath the bridges starts to fade, peel or flake over time with the influence of the elements of weather. In addition, steel, iron and other ferrous objects start to corrode over time with the impact of moisture in the atmosphere. Corrosion is a huge problem across many industries and billions of dollars are spent on restoring ships, bridges, jetties, pipelines, etc. Even historical monuments lose their shine, become dirty, develop rust, and without restoration, are likely to crumble.
Restoration can be efficiently and effectively done with the right technology. There are many ways of cleaning and removing paint or corrosion namely – chemical stripping, thermal stripping, manual sanding, dry sandblasting, high-pressure water cleaning, and wet abrasive blasting. However, all these methods with the exception of wet abrasive blasting, have limited applications due to the risks associated with hazardous chemicals, damage to the substrate or are inefficient.
In this article, you will get to know what is high-pressure water cleaning, what is dustless blasting or wet abrasive blasting and why dustless blasting is a compelling option for surface preparation.
2. What is high-pressure water cleaning?
A high-pressure water cleaning unit consists of a positive displacement pump driven by an electric motor and the pump draws the water continuously from a faucet and pumps out high-pressure water (the pressure can be 2000 PSI or more). The hose connected to the outlet of the pump is used to produce a high-pressure water jet at the other end of the hose by using a variety of nozzles.
High-pressure water cleaning uses only pressurized water for cleaning the surfaces and it is effective for cleaning dust, oil, grease, grime, and cobwebs, from surfaces and walls. However, it is not effective for the removal of paint from external surfaces such as steel, timber, automotive vehicles, and steel structures.
3. What is dustless blasting?
Dustless blasting also known as wet abrasive blasting or vapour blasting is the process of sandblasting whereby dust is suppressed by using a slurry mix of abrasive and water propelled by compressed air. In some ways, it can be considered a combination of high-pressure water cleaning and abrasive blasting. Dustless blasting has the advantage of pressurized water but still be able to remove rust and paint using the impact of abrasive media without the dusty environment of sandblasting.
The process of dustless blasting involves mixing the water and recommended abrasive inside a pressurized blast tank and the mixture of air, water, and the abrasive is forced onto the surface being blasted. The force required to blast the surface is provided by compressed air.
During dustless blasting, water will encapsulate the particles of the abrasive and the particles of the stripped surface coating into it. The abrasive particles and the stripped coating particles encapsulated in the water form a combined mass and fall onto the ground due to gravity. Hence, the surrounding environment is free from dust to a great extent.
Dustless blasting is an efficient method or technique for removing coating or paint from surfaces. It is superior to high-pressure water cleaning since it cleans the surfaces faster and it is efficient for jobs like removing powder coating from steel structures, equipment, and paint from cars, concrete and timber.
When it comes to stripping coatings and paints from surfaces, dustless blasting is better than high-pressure water cleaning because it uses a combination of abrasive and water. The wet abrasive particles remove the coating from the surface, but at the same time, the abrasive particles will not break and spread in the air due to the presence of water. The water encapsulates the dust, dirt, and debris and falls to the ground for easy cleaning.
The presence of water in dustless blasting will eliminate the risk of sparks or a cloud of dust. Hence, dustless blasting can be executed even in open surroundings with nearby workers doing other work.
4. When should you choose dustless blasting over high-pressure water cleaning?
Both the processes have their application and the choice between dustless blasting and high-pressure water cleaning depends on the application, the coating that you are trying to remove, and the substrate.
- If the primary business is in the field of removing (stripping) paints, coating, and stains from automobile bodies, external of homes, wooden log cabins, walls, bridges, roads, surfaces damaged by fire, and similar jobs then the sure choice is dustless blasting.
- High-Pressure water cleaning is good for removing dust and grime but not much more. It cannot remove rust and paint or powder coat.
- For such applications, dustless blasting not only does an efficient job but is also a lot quicker compared to high-pressure water cleaning.
- A high-pressure water cleaner takes more time and uses much more water than a dustless blaster (High-pressure water cleaning uses about 20-30 litres per minute compared to wet abrasive blasting which uses less than 1 litres per minute). Apart from being more environmentally friendlier, in places where water is not freely available, wet abrasive blasting is more suitable.
- High-pressure water jet cleaning can damage the underlying substrate. On the other hand, wet abrasive blasting offers a choice of media abrasives with varying levels of hardness to suit the coating and the underlying substrate. Modern cars are using lighter and thinner materials such as aluminum and fiberglass.
- Line marking removal is an application where high-pressure water jet cleaning is used extensively however, the water usage is very high and it causes damage to the surface. Unlike high-pressure water jet blasting, wet abrasive blasting can also remove thermoplastic paint used in modern times. The only other alternative is grinding the surface which is not only dusty but removes a significant layer of the substrate and wears it down.
- A commercial high-pressure water cleaner operates between 3000-50,000 PSI whereas dustless blasting needs only 30 to 150 PSI to do its job. It provides a feather finish and no damage to the substrate.
5. Pros and cons of dustless blasting v/s high-pressure water cleaning
Pros of dustless blasting:
We have discussed dustless blasting in detail in the preceding paragraphs. Let us summarize the pros of dustless blasting compared with high-pressure water cleaning.
- Dustless blasting is very effective and works efficiently for stripping and cleaning jobs compared to high-pressure water cleaning.
- Dustless blasting uses a mix of water and abrasive and can create an anchored profile (textured surface) for the new painting or coating to stick to it and stay strong for a longer time.
- An anchor profile is highly desirable on metal surfaces that are to be restored, like the body of a car or boat, metal bridge, etc. However, if the anchor profile is not required on some surfaces (like timber surfaces), the profiling can be avoided by selecting a softer grade of abrasive.
- Dustless blasting can be used for removing thermoplastic paint used for line marking on roads.
- A dustless blasting unit is suitable for working even at sites with water scarcity.
Cons of high-pressure water cleaning
High-pressure water cleaning costs less than a dustless blasting unit, and its low operative cost makes it economical for cleaning jobs. It works effectively for removing dust, oil, grease, grime, and cobwebs, from surfaces and walls. However, when it comes to stripping paints and coatings from surfaces, high-pressure water cleaning is no match to dustless blasting. Let us summarize the cons of high-pressure water cleaning compared with dustless blasting.
- High-pressure water cleaning works effectively for cleaning but it is not effective for removing paint, rust, powder coating, etc.
- Under normal pressure, high-pressure water cleaning does not change the underlying (original) surface, however using a very high-pressure narrow jet can change the underlying surface, but the object may be damaged.
- High-pressure water cleaning does not profile the substrate surface without an etching agent and it is very hard to arrange its safe disposal.
- High-pressure water cleaning can clean the wooden surface to remove grime and dirt, but cannot remove the wood stain.
- The high-pressure water cleaning unit needs a dedicated water supply, hence, not suitable for working at sites with water scarcity.
Both dustless blasting and high-pressure water cleaning have their own niche applications.
High-pressure water cleaning is more suited and economical for cleaning dust, oil, grease, and grime from surfaces.
On the other hand, dustless blasting works effectively for removing paint, powder coating, and rust from the surfaces. Dustless blasting can create an anchor profile (textured surface) on the surface for the powder coating and paint to adhere well and protect the asset for a long time
7. About RapidBlast™
RapidBlast TM is a truly Australian made product and offers cutting-edge technology in wet abrasive blasting. Unlike some systems that use a basic venture system, RapidBlast™ uses a precision needle valve to regulate and optimize the flow of abrasive media. Through continuous improvement, it is the equipment of choice for dustless blasters all over Australia and is gaining popularity overseas as well. It comes with a very affordable price tag and at half the cost of some of its competition.
The RapidBlast Dustless Blasting Equipment is designed, manufactured, and assembled by Quantum Blast Technologies in Australia and is suited for the harshest operating conditions.
For more details, please visit RapidBlast .