What Is Sandblasting?

What Is Sandblasting?

Sandblasting is the process of using pressurized air with abrasive media, to clean, smoothen, or scratch surfaces. It also involves using the same process to sand or removes dirt, dust, old paint, and unwanted particles/substance from the surface of a material. 

What is Sandblasting used for? 

Sandblasting is used to remove old paint, scratches, dust, rust, casting marks, and particles from the surface of a material. It can also be employed to change the condition of the surface of materials like wood, plastic, etc. 

Over the years, sandblasting is one of the efficient ways employed by industries and individual operators, such as woodworkers, machinists, and auto mechanics to clean and prepare surfaces. 

From the name “sandblasting”, one would think sand is the only media used in the process of sandblasting, but that is not so. 

You can sandblast different materials with various sandblasting media, but this depends on the material being worked on. 

Sandblasting isn’t only used in industries, it can also be used on household materials/ tools. 

Types of Sandblasting:

There are different types of sandblasting which are used to achieve one purpose; Smoothen the surface of materials by the use of a specific type of grit. I hope you will be able to choose which of these methods would be suitable for your type of job. Let’s get down to discussing each of them;

1. Silica Sand or Silicon Dioxide: 

Ordinary sand is also known as silica sand. It’s what you see every day. 

This is a type of sandblasting used in recent times but was banned in some countries because silica can lead to some types of respiratory diseases like silicosis. 

It is the process of removing particles and impurities as the case may be from the surface of a material using sand as the abrasive media. 

Why is it efficient? Sand particles have almost similar sizes and the edges are sharp. It’s best used on various surfaces that require versatility. 

2. Soda blasting:  

As the name implies “soda”, I’m sure the household baking soda comes to mind, yes you are right. 

Baking soda or bicarbonate of soda is the abrasive media used for this type of sandblasting. 

Unlike sand, soda can easily remove rust from metals without causing stripping, depression, or damage to the metal beneath the rough surface that is being sandblasted. 

The use of soda sandblasting has proved effective in removing impurities from the surfaces of materials.

 It doesn’t require much exerting pressure, which makes it one of the best for cleaning softer surfaces like glass, chrome, and plastic. The disadvantage is that soda blasting media cannot be recycled. 

3. Steel grit blasting

This can easily be defined from the name; it uses spherical steel as abrasive media. It is commonly used to remove paint, rust, and impurities when working on a metallic surface. 

One of the advantages of steel grit blasting is its fast-cutting nature and ability to perform a smooth finish on metal. 

4. Bristle blasting: 

This is a type of sandblasting that works independent of abrasive, in another word, no abrasive media has to be projected onto a surface prepared to be cleaned.

It involves directly rotating bristles against the surface of the metal to remove impurities. It completely removes corrosion from the surface of the metal. 

5. Glass Bead: 

Glass bead blasting is mostly used on cabinets. It uses grit at the abrasive media which polishes the surface of the material being sandblasted, due to the fine nature of the grit. 

If you are working on the matte and satin finish, this is one of the best methods you can go for. 

6. Dry-ice blasting: 

This isn’t as common as the types discussed above because it is a newer and innovative type of sandblasting.

It works on the principle of cleaning surfaces by projecting high-pressure air pressure along with carbon dioxide pellets on the surface of the material. 

The dry-ice pellets are made by freezing liquid carbon dioxide at extreme temperatures.

The advantages of dry-ice blasting are how fast and clean the method is, its environmental-friendliness, non-reactiveness, it doesn’t cause damage to the surface and it’s used for cleaning sensitive electrical components. 

7. Pencil blasting: 

It is the process of mixing high-pressure air with a fine powder to produce an abrasive media, which is in turn used for cleaning surfaces. 

This type of sandblasting is best used when precision is required. It is also used for glass etching. 

8. Centrifugal Blasting: 

Another name for this type of sandblasting is wheel blasting. 

It works on the pneumatic principle, that is, a motor-operated blade wheel is used to throw the abrasive media towards the surface of the material being cleaned at relatively high velocity.

 Its advantages are; it doesn’t make use of compressed air pressure, abrasives used can be recycled. However, it is not portable and can’t be applied on uneven services. 

Essential Sandblasting Equipment:

1. Sandblaster gun and nozzle:

A sandblaster nozzle is a piece of device that accelerates/directs air and abrasive media over the surface of a material for effective sandblasting. The sandblasting nozzle directs the abrasive media at a suitable and appropriate angle towards the material being sandblasted. 

The length of the nozzle and tapered design are the major factors in determining the pattern and speed of the abrasive materials coming out of the nozzle. 

A sandblaster gun is a device that applies pressurized air to force abrasive media through the nozzle. 

2. Sandblaster cabinet: 

The blast cabinet is a medium-sized box that allows an operator to recycle their chosen abrasive. The abrasive is returned into the cabinet to be recycled and reused.

The material being recycled is not damaged or contaminated in any way, hence there’s no disadvantage.  

A good sandblasted cabinet comes with armholes, where the operator can put his hands in the gloves. 

3. Sandblasting media:  

This is very vital to the sandblasting process and having the right one at your disposal is possibly the best tool at hand. 

Sandblasting media are used for the following applications; Stripping, cleaning, etching, polishing, polishing, and strengthening. 

In choosing a good and suitable sandblaster media, you need to consider whether the media is grit or mesh size and the nature of the work required. 

There are varieties of sandblaster media such as aluminum oxide, silica sand, crushed glass, glass beads, plastic abrasive grit, steel shot, walnut shell, etc. 

4. Air compressor: 

The major function of an air compressor is to deliver the high-pressure air needed for an effective blasting process. Knowing the right air compressor makes the job easy. 

For instance, you need an air compressor of 10 CFM-20 CFM and 18 CFM-35 CFM for smaller and larger tasks respectively. While 50-100CFM is needed for industrial types. 

5. Sandblasting hood with an air supply: 

The process of sandblasting is sometimes dangerous due to the dangerous media and release of abrasive material at a relatively high speed. 

The job of a sandblasting hood is to protect the face and head of the operator from any abrasive material released with force. 

The headgear is made of extremely durable fibers that offer high protection and also come with an air supply for the operator’s convenience.

Check More Sandblasting Tools

Step-by-step process of Sandblasting

Discussed below is the list of actions that an operator must follow for an effective, safe, and successful process of sandblasting.

Step 1: Set up your work area

Check and remove from your working environment unwanted and sensitive materials that may be hit by the abrasives being released with force.
 
You can avoid sandblasting what you don’t want to be sandblasted by setting a boundary (trap) over it. 

Ensure your work area is well ventilated to prevent difficulty in breathing when you put on a nose mask.

Step 2: Put on your safety gears

You need to put on your safety gear such as protective goggles, helmet, gloves, and coverall before starting your process of sandblasting. 

If you don’t have a safety coverall, wear tight long sleeves to completely cover your body.

Step 3: Setting Up Sandblaster

To set up your sandblaster as required, you need to read the owner’s manual and follow all written instructions.
The first thing you need to do is to close the valves on the blasting unit. 

Your tank needs to be filled with abrasives such as silica sand, walnut shell, glass, corn cubs, etc, using a plastic funnel.

Step 4: Setting Up Pressure 

The next step is to open the main air valve and allow the pressure tank to reach a pressure of 40 PSI, which varies depending on what type of equipment you are using.

Open the sand air valve after you have completely pressurized the tank.

Step 5: Blasting

Now you are ready to blast, but before then, ensure all valves are closed and direct the nozzle towards the surface of the material ready to be blasted at a small angle.
 Now, you can face the nozzle towards your target and sweep using controlled motion.

Step 6: Last Settings: 

We are at the final settings, slowly increasing the pressure to give effective results.

Gradually increase till the pressure gets up to 100 PSI and check the results.

Recheck the result to see if you get the desired result. After all, steps have been followed, ensuring all the valves and nozzles are closed. 

Materials Which Can Be Sandblasted?

As it was earlier discussed, sandblasting is using a piece of abrasive material to remove contaminants from surfaces. Before sandblasting, it is important to know the type of material that can be sandblasted. 

  • Silver
  • Wood
  • Glass
  • Brass
  • Aluminum
  • Plastic steel
  • Metals
  • Stones 

Top five applications of Sandblasting

1. Strip off paint and corrosion: 

Stripping off paint and corrosion from the surface of a material is not easy and trying to strip off using chemicals may lead to undesirable reactions with the metal.

Adopting sandblasting is the fastest, clean, and best method for removing paint and corrosion from the surface of the metal. 

2. Prepares surface for coating activity: 

Sometimes, metal or plastic parts need to be coated if they have some irregularities. Sandblasting is an effective way to prepare the surface before adding paint or finish. 

After sandblasting, your surface will be ready for painting, bonding, and coating. Any surface that isn’t prepared before coating will lead to a failed coating operation. 

3. Smooths and polishes devices: 

Sandblasting leaves the surface of the material sandblasted shiny and polished. 

Not only does sandblasting clean, smooths, and polishes surfaces, it’s also an effective way to remove burs, tags, and excess materials that come with metals or plastic parts that need to be assembled. 

4. Cleaning automotive: 

Sandblasting can be used to clean automotive. It ensures the removal of paint and rust from the surface of your car. 

Which in turn provides a prepared surface that is clean before painting. 

5. Restoration:  

You can restore your household equipment to its original, attractive and unique look by sandblasting. It will remove rust, old paint, and other impurities from your materials. 

Advantages of Sandblasting

  • Sandblasting has aggressive action on the surfaces of the material being sandblasted, thereby cleaning the surface.
  • Sandblasting is a powerful action capable of removing contaminants from rough and tough surfaces. 
  • It is a fast and clean method for removing deposits of the contaminants rapidly from the surfaces of materials like metals, wood, etc.
  • The process of sandblasting does not involve big and complex machines for operations. 

Disadvantages of Sandblasting

  • It is not fit for cleaning smooth surfaces because of the abrasives used. However, you can make use of soda blasting for soft surfaces instead of sandblasting, which is capable of damaging the surface. 
  • The abrasives used in sandblasting are very rough, which can wear away the surface of the particles if used regularly for particular surface preparation. 
  • Silica can lead to health hazards, this led to it being banned in some countries. 
  • The operation of sandblasting generates lots of heat which is hazardous to health, due to its projection of particles at a relatively high speed. 
  • Before anyone can operate a sandblaster, he/she needs to take preliminary precautions to prevent damage to the sandblaster, surface, and the operator. 

FAQ:

Is Sandblasting dangerous? 

Yes, it is. Why? Because of the high exposure rate of toxic silica in the air during operation, which is hazardous to the operator. 

Can you reuse Sandblasting sand?

Sandblasting sand cannot be reused after the process of sandblasting, since materials that were cleaned off the surface may be contained in it. However, it can be recycled into other materials like concrete or cement. 

Is there any alternative to Sandblasting? 

Yes, there are alternatives to sandblasting. One of which is laser cleaning. It can also be used to remove rust and paint, but laser cleaning makes use of laser ablation to remove contaminants. 

Conclusion

Finally, sandblasting is a widely adopted process that is versatile and used in industries and homes. Now you know about the process, equipment, and different abrasive materials. Don’t forget to take precautions before starting your sandblasting process.

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