Sand Blasting Bricks: Pros And Cons

Sandblasting brick is a popular method for removing paint, mildew, and graffiti from brickwork. However, it is important to exercise caution when sandblasting bricks as they have a protective film that can be eroded if the pressure is too high or the nozzle is too close to the wall. Sandblasting brick can also be dangerous due to the silica particles produced, which can be harmful to one's health. Therefore, it is recommended to hire a professional company with the appropriate safety equipment and expertise to perform the task.

Sandblasting old brick

Old brick buildings have a tendency to be painted over by owners looking to improve their look. However, many people want to return to the original brick look. Sandblasting is often the first thought for paint removal, but it is not always the best method.

How Old Bricks Were Made

Bricks are made from clumps of clay mixed with varying degrees of shale and sand. Before the mid-1800s, most bricks were formed by hand and left to dry for a couple of weeks before being placed in a kiln. The kiln was often built using these "green" bricks, which were then cooked at a lower initial temperature to remove any remaining water. Once dry, the temperature was increased to around 1800°F. After cooling, the kiln was disassembled, and the bricks were sorted. This early brick-making process resulted in softer and less consistent bricks than those made today.

What Sandblasting Does to Old Brick

Sandblasting removes paint from bricks, but it also removes the outer skin, leaving the brick exposed to the elements. This can cause the brick to slowly self-destruct and turn into powder, a process known as spalling. Sandblasting can also cause small cracks to widen, and bricks to become more porous.

An Alternative to Sandblasting

Instead of sandblasting, chemical paint stripping is recommended. Products like PeelAway1 can effectively remove paint from brick without causing the damage associated with sandblasting.

Sample Service

If you are unsure about exposing the masonry on your property, some companies offer a sample service. They will carefully remove a square meter of pebble dash or render and then sandblast the masonry so you can see the potential results.

Sandblasting equipment

Portable Sand Blasters

Portable sandblasters are ideal for small to medium-sized projects and offer high mobility. They are easy to move around and can be used in various locations. Portable sandblasters are commonly used for cleaning and stripping surfaces, such as metal, wood, or concrete. They use compressed air to propel abrasive media onto the surface, removing contaminants, paint, or other coatings.

Blast Pots and Machines

Blast pots, also known as pressure blast systems, are suitable for intensive and large-scale projects. They are often used in industrial settings and can handle a wide range of abrasive media. Blast pots use compressed air or water pressure to propel the abrasive media through a nozzle, allowing for aggressive and efficient surface preparation.

Abrasive Recycling and Vacuums

Abrasive recycling systems are designed to recover and recycle the abrasive media during the sandblasting process. This equipment separates the used abrasive from debris and contaminants, allowing for reuse, which can reduce costs and minimise waste. Vacuums are used in conjunction with abrasive recycling systems to collect the spent abrasive and debris, ensuring a clean and safe work environment.

Blast Cabinets

Blast cabinets provide a controlled environment for sandblasting operations. They are enclosed structures that contain the abrasive media and debris during the blasting process. Blast cabinets are commonly used for smaller projects or when precision blasting is required. They come in various sizes and configurations, offering a safe and efficient solution for surface preparation.

Nozzles, Hoses, and Accessories

Nozzles are an essential component of sandblasting equipment. They are designed to accelerate and direct the abrasive media towards the surface being treated. Different nozzle sizes and designs are available depending on the application and the desired blasting pattern. Hoses are used to supply compressed air or water to the blast pot or nozzle, ensuring consistent and controlled blasting.

Respirators and Safety Gear

Sandblasting can generate dust, debris, and hazardous particles, so proper respiratory protection is crucial. Respirators or blasting helmets with air supply ensure that operators breathe clean air and are protected from airborne contaminants. Safety gear also includes blast suits, gloves, safety glasses, and ear protection to safeguard against flying debris and noise.

These are just some examples of sandblasting equipment used in various industries. It is important to select the appropriate equipment for the specific application and always prioritise safety when performing sandblasting operations.

Brick cleaning abrasives

When considering the type of abrasive to use, it is important to take into account the age and type of brick. Older bricks tend to be softer and more susceptible to damage from abrasive cleaning. Even new, fired bricks can be damaged by abrasive cleaning. Alternative methods such as chemical stripping or power washing may be more suitable for certain types of brick.

Walnut shells or equivalent abrasives have been used with some success. However, it is important to note that even these milder abrasives can damage the brick if not used properly. Sandblasting should not be the first choice for removing paint from brick, especially older brick. It can cause significant damage to the brickwork and destroy the finished look of the brickwork.

If you decide to use abrasive cleaning on your brick, it is important to take the necessary safety precautions. Silica particles can be harmful to your health, so proper safety gear and PPE are essential. Cleanup is also an important factor, as the sandblasting process can leave behind a lot of residue.

Safety gear

Sandblasting is an extremely dangerous activity that can cause serious harm to the body if the proper safety gear is not worn. The dust created by sandblasting contains harmful irritants that can cause long-term health issues such as silicosis, irritated eyes and lungs, and painful skin damage. Therefore, it is crucial to wear the appropriate safety gear when sandblasting.

• Respiratory Protection: A dual respirator filter mask is recommended to protect against the inhalation of abrasive dust. If this is not available, a cheap dust mask is better than nothing.
• Eye Protection: Safety glasses or goggles should be worn to protect the eyes from flying debris. Air-supplied helmets are an even safer option, especially when blasting in an enclosed space or outdoors.
• Clothing: Long sleeve shirts and long pants are recommended to protect the skin from potential blasts. Professional sandblasting suits are ideal as they are made of heavy material that completely covers and protects the user's body.
• Gloves: Gloves made of synthetic protective material or leather should be worn to protect the hands.
• Footwear: Sturdy shoes are recommended to protect the feet in case of blasts.

It is important to prioritize safety when sandblasting and ensure that all safety gear is properly fitted and worn correctly.

Sandblasting alternatives

Sandblasting is a process that involves refinishing a surface, typically for cleaning and/or renovation purposes. While it is considered an ideal choice in certain situations, there are now many alternative methods and materials that are safer, more environmentally friendly, and less damaging to the surface being treated.

Agricultural Media Blasting

This method uses ground-up nut shells, seeds, and kernels from organic foods as an abrasive. It is an ecological process that makes use of food processing and preparation waste. It is not as abrasive as sand, so it is suitable for cleaning surfaces without damaging the underlying material. It won't damage the original finish of the surface, but agricultural media may not be readily available in every market.

Bead Blasting

This method uses small glass beads that break up on impact, removing surface residue and contaminants. It is a popular application for surfaces contaminated with fungal growth and can also be used to remove calcium from around pools, fountains, and other water features.

Dry Ice Blasting

Dry ice is used as the media in this method, and it is popular across a variety of industries. It does not create any contaminants that can be harmful to health, although it does need to be handled safely. It will not damage the surface it is being applied to and there is no leftover residue aside from the broken-down remains of the material being removed. A simple hose wash will usually complete the cleaning process.

Industrial Ice Blasting

This method uses compressed air to accelerate media towards the surface that is being cleaned or prepared. It differs from dry ice blasting as it uses water that is frozen and utilised as media, rather than solid carbon dioxide. It is energy-efficient, reliable, and requires little maintenance. It leaves no residue and is more environmentally friendly than conventional blasting methods.

Chemical Stripping

Chemical paint strippers are a popular alternative to sandblasting. They are safe and effective, although more labour-intensive. Soy- and citrus-based strippers are low in VOCs and less harmful to health and the environment. They will not damage the face of the brick or the decorative mortar.

Frequently asked questions