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Tips for Selecting Abrasives for Blasting Media

Posted by Kevin Hughes | Sep 28, 2018 11:15:00 AM

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Do you have a project that needs to be repainted, but first needs to be stripped and you are not quite sure what type of abrasive you will need? Maybe you have tried your hand at blasting, but you feel that you might not have used the correct type required to make it look like you wanted. Perhaps you are not sure what media blasting is good for, so we will first go over what it can do and then present some of the best abrasives to use for specific jobs.

Abrasive blasting has been around for at least one hundred and forty-eight years and is used to strip, shape, restore and clean surfaces. The size and type of the surface can determine what kind of blasting unit will be used, as well as the type of abrasives that you will need. For instance, if you are working with a project that’s exterior is even and firm, you will need to put an Anchor pattern on it. An Anchor pattern is when the abrasive that you are using leaves little dents in the surface, and the distance from the top of a peak (dent) down to the lowest part of the surface is recognized as the depth profile. Once these tiny little peaks and valleys are on the surface, it is easier for the coating of your choice to be put on.

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Abrasive Types

There are too many abrasive types to list, but we are going to focus on six, which are:

  • Grit and Sand – Silica sand (which can cause health issues and should only be used if needed) was used initially, but now there are other choices. The best uses for sand are: removing paint, varnish or stains, corrosion and buildup that is on concrete, stone, brick, wood ceilings or beams. Once the job is complete the surface should be clean so that you can either apply a coating or keep it in its natural state.
  • Glass Bead – This abrasive is recyclable soda lime glass that can be utilized up to one hundred times, so this is a great one to use if your objective is a glossy appearance and cost-effective
  • Synthetic – This includes plastic beads and sodium bicarbonate, best used in cleaning. With synthetics, you will be able to clean many different types of delicate surfaces without running the risk of damage. In the nineteen-eighties, this was the treatment that was chosen to be used in restoring The Statue of Liberty. Baking Soda is a fantastic abrasive to use on surfaces that need deodorizing, such as for fire refurbishment. The one big drawback to utilizing it is if using near any plants it will destroy them, so you must take precautions.
  • Water and Vapor – Some of the little to no dust abrasives are done using water and can be mixed with some of the other abrasives, such as baking soda. You can also blast utilizing a sponge jet in this type of method. All of the water, vapor and sponge blasting can be used for things that need to be gently removed.
  • Dry Ice – The use of a mixture of water and dry ice and is an excellent choice for little to no media or residue left over. This is also a good choice in the case of being accepted for food safety products.
  • Coal Slag – This is made from crumpled coal and is somewhat easy to manage for the cost. It is used best for preparing a piece for painting.

Angularity Classification

The shape of the abrasive will help to determine just how large or how small the peaks and valleys will be. Particles that have an angular shape are best used to slash across coatings that are soft, as well as rust and clean much faster than the rounded particles; these types also leave a more defined anchor pattern. If you need a smoother, peened exterior then using a rounded particle is what you will need.

The different shapes and the type of abrasives are:

  • Angular – Coal Slag and Crushed Glass
  • Sub-Angular – Garnet, Olivine and Plastic
  • Sub-Rounded – Staurolite and Walnut
  • Rounded – Glass Bead and Silica Sand

As you can see, there are a lot of different types of abrasives to choose. So it is best when you are going to start a project, whether it is big or small, using a blasting cabinet, open air portable blast pot or a blast room, you will need to figure out how you need your finished product to look. If you are unsure if you can accomplish the right results, consider using a knowledgeable company to do it for you.

Topics: Industrial Projects

Written by Kevin Hughes

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