CHOOSING A SANDBLASTING CABINET

Whether you’re searching a sandblasting cabinet for your shop or for your personal garage, there are several things to consider before purchasing this important industrial tool.

Sand blaster cabinets, also known as media blast cabinets or abrasive blasting cabinets, are metal boxes with openings, windows, and attached gloves which allow you to use sand or another abrasive media form, to smooth rough surfaces, remove imperfections in metal, and scrap of old paint or rust.

Yet, while all sandblast cabinets are made for the same general purposes, there are many different specifications.

Types of Sand Blasting Equipment

Sand blasting machines are made in a few different styles: standard, split-level, and portable. While all three styles operate in similar fashion and can use various types of blasting media, there are significant differences to each. Choosing which style will work best for you depends on how often you want to use your sand blaster and for what purposes.

Standard

These fixed cabinet blasters have openings in the front and on both sides of the machine. They’re great for working on small to medium sized objects.

Split-level

Split-level blaster cabinets are also fixed and have a hatch top that opens upward on a hinge to create a larger work space. These cabinets are useful when working on larger or heavier objects.

Portable

Portable sand blaster cabinets, sometimes called mini sand blasters, are perfect for working with smaller or more delicate objects because they allow your to make more detailed alterations. And, of course, benchtop sandblast cabinets are completely movable, making jobs outside of your workshop or garage possible. They offer remote control operation and are usually more inexpensive than other types of sandblaster cabinets for sale.

Once you’ve chosen the best sandblasting equipment style for your needs, the next decision you should make is whether you want to use a siphon cabinet or a direct pressure cabinet.

Types of Blasting Systems

The question here is how you want your machine deliver your abrasive media to the blasting nozzle.

Siphon Blasting Cabinets

Siphon cabinets, also known as suction cabinets, are best for light to occasion use, general cleaning and light production jobs. They use a gun to pull abrasive media into your blasting nozzle where it is then shot from the end of the nozzle. This requires the use of more air pressure than direct pressure cabinets because the delivery is a two-step process.

However, these systems are easier to use and install and are generally less expensive than direct pressure cabinets.

Direct Pressure Cabinets

These machines can expel abrasive media at a higher blasting flow rate than siphon blasting cabinets can because, unlike the siphon delivery, this system pushes the abrasive media out directly, making completing your jobs on average much faster. The direct pressure cabinets also allow you to lower and raise the pressure to customize the flow rate for each job you do.

Aside from these choices, there are other considerations too. Media blast cabinet details varies with each model and some have better features than others.

Details and Features

Here are some helpful tips and warnings to guide you through the details and specs of the blasting machines you’re considering.

Doors

If you’re buying a standard cabinet, make sure you know what material the cabinet doors are made of. Avoid cabinet blaster machines with plastic doors, which can warp and bow out easily and could lead to machine malfunction.

Air Compressors

Some Sandblast cabinets are sold with their own air compressor unit; however, not all are. If you’re thinking about purchasing a sandblast cabinet without an included air compressor, make sure to check the required PSI and CFM for your new sandblast cabinet to check if it with work with your current air compressor.

Construction

The metal used for frame and body construction also impacts the quality and durability of your sandblasting cabinet. While machines with lighter steel bodies are cheaper and work fairly well for occasional use, if you’re planning on using your blasting cabinet on a regular basis, you will need to invest in a machine with a sturdier construction, such as heavy gauge steel.

Lighting

Some cabinet blasters come with interior lighting. While this is not always necessary for daily use, if you want extra, focused lighting to help you in your detailed work, a sandblast cabinet with an interior light is ideal.

Assembly

Another, more humdrum consideration is whether the cabinet you’re purchasing is fully constructed or will require assembly. Sand blasting cabinets may require hours of assembly and the assembly could be quite complex, especially if you have no prior knowledge of how these machines are built and work.

So, once you’ve decided on the types of sandblasting cabinets and systems and thought about the specific features you want, you can start shopping the sandblasting machines for sale.

Personal Use

Before deciding on which type of sandblasting cabinet to purchase, you should ask yourself these questions to help you narrow your search and ensure you find the sand blasting machine that fits your needs:

· What do I want to use my sandblasting cabinet for?

· How often do I want to use my sandblasting cabinet?

· What is my price range?

· Where am I going to use my sandblasting cabinet?

Knowing the answers to these questions will greatly reduce the time you spend deciding between different sand blasting machines.

Conclusion

In the end, the perfect sandblasting cabinet for you is out there. You just need to think about what features, styles, and specification will work best for what you want to use your sand blast cabinet for!

 Next Step:  Buy Abrasive!

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Sandblasting Nozzle Sizing Chart

Use This Chart To Find Your Nozzle Bore Size:

  • #2 Nozzle has a 1/8″ orifice (3.2mm)
  • #3 Nozzle has a 3/16″ orifice (4.8mm)
  • #4 Nozzle has a 1/4″ orifice (6.35mm)
  • #5 Nozzle has a 5/16″ orifice (8mm)
  • #6 Nozzle has a 3/8″ orifice (9.5mm)
  • #7 Nozzle has a 7/16″ orifice (11.1mm)
  • #8 Nozzle has a 1/2″ orifice (12.7mm)
  • #10 Nozzle has a 5/8″ orifice (16mm)
  • #12 Nozzle has a 3/4″ orifice (19mm)

 

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Sandblasting Profiles: What abrasive should I use?

Anchor patterns are extremely difficult to approximate due to the many variables at play.  Use this information with Caution!  This is only an approximation.

The type of metal use in this example was hot rolled steel with tightly adhering mil scale.  The type and hardness of your substrate, how thick the scale is, the degree of cleaning you are attempting to achieve, experience and skill of the person performing the sandblasting, etc will all factor into your end result.

In this example, the pressure blasting was done using a 90-100 psi nozzle pressure.  The depth of the anchor profiles listed below are approximations only, and are on average.

1 Mil Profile:

1.5 Mil Profile:

2 Mil Profile:

2.5 Mil Profile:

3 Mil Profile

 

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What Is Friability?

What Is Friablity?  Short Answer:  How easily/quicky a media shatters on impact and breaks down.  Think of Friability as durability.  This is different from Hardness Rating.  Sandblasting medias may have the same Hardness rating, but completely different Friability Ratings.   One will break down fast, the other will remain intact and can be recycled multiple times.

Brown Fused Aluminum Oxides have a LOW friability, so it will break down slowly, and coarser sizes can be recycled multiple times.

White Fused Aluminum Oxides have a HIGH friabilty, but the SAME HARDNESS rating of Brown Fused Aluminum Oxides.  Even though it is just as hard as Brown Fused AO, it will shatter on impact and break down quickly, without doing as much damage/impact to the substrate.  This is one reason why it is often used for delicate glass etching, and why it makes a nice final polish for rock tumbling.  Its high hardness rating however, makes it appropriate for anti skid flooring applications, traction, etc.

Sinterblast, or Sintered Aluminum Oxide has a MEDIUM friability.  Think of it as the middle ground between Brown Fused and White Fused.  It can be recycled in coarse sizes, but will not have the long life (durability) of a Brown Fused Aluminum Oxide.  It is often preferred by Powdercoating companies due to its lower cost.  If you are just taking off mil scale prior to coating, this is a great media to try out.  It is a lower purity aluminum oxide, and cheaper in cost to manufacture due to the sintering process being less expensive than the fusing process.  THE MEDIUM FRIABILITY OF THIS TYPE OF ALUMINUM OXIDE IS WHY YOU BLAST AT A 60 PSI, AND NOT THE USUAL 80-90 PSI OF BROWN FUSED ALUMINUM OXIDE.  ANYTHING HIGHER AND YOU WILL NOT ACHIEVE GOOD RESULTS BECAUSE THE MEDIA WILL SHATTER UPON ITSELF IN THE AIR STREAM BEFORE GETTING TO YOUR SUBSTRATE.

When choosing an abrasive to use, make sure you take into consideration its friability, not just hardness rating.  Our product descriptions of our sandblasting abrasives include both hardness ratings and friability ratings.

 

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Number One Cause Of Premature Coatings Failure

The most common cause of premature coatings failure is improper ANCHOR PATTERN.

What is anchor pattern?  It is a term used to describe the roughness (etch, or profile) that is created on a surface when sandblasted.  The Anchor Pattern is measured in 1/1000th of an inch, which is called a MIL.  Paint coatings are also measured in MILS as well, making it a term that is easy to remember.

Coatings require specific mils of anchor pattern in order to properly adhere to the surface it is applied to.  Each coating will have different requirements.  Therefore, you cannot simply sandblast a surface clean and then apply paint to it without technical information on what mils profile that particular coating requires (among other factors).  If you simply guess at what profile you need, you risk premature coatings failure.

If you have no access at all to the coating manufacture’s technical data and need to make an educated guess, you will want to consider the following rule of thumb:

The mils of anchor pattern you create on the surface to be coated, should be 25 to 30% of the DRY film thickness of the total coatings system BUT NEVER greater than the dry film thickness of the primer coat unless additional coats are to be applied immediately.

Also key to understand is that the wet mils of a coating will be different than the dry mils of a coating.  Many coatings shrink tremendously, depending on the percentage of solids contained within them.  Make sure that the anchor pattern you create when sandblasting is much shallower than the total coatings when dry.

Other factors that impact the development of anchor pattern include the type of steel you are blasting (including hardness and chemical composition), how the steel was formed, prior use of the steel, the type of abrasive you use to create the anchor pattern (including size, shape, hardness, and velocity), as well as what type of blast nozzle you choose to use and how you use it (such as angle and distance to the work surface).

The chart below is a crude approximation of abrasive size to anchor pattern, and should thus be used only as a starting point only for both centrifugal wheel and pressure blasting.

  • 1 Mil Profile = G80 Steel Grit, 100 Mesh Garnet, S110 Steel Shot, 3060 Coal Slag
  • 1.5 Mil Profile = G50 Steel Grit, 100 Mesh Garnet, S170 Steel Shot, 3060 Coal Slag
  • 2.0 Mil Profile = G40 Steel Grit, 3060 possibly also 80 Mesh Garnet, 36 Grit Aluminum Oxide, 3060 Coal Slag, 3060 Copper Slag
  • 2.5 Mil Profile = G40 Steel Grit, 3060 Mesh Garnet, 24 Grit Aluminum Oxide, 2040 Coal Slag, 2050 Copper Slag
  • 3 – 4 Mil Profiles = G25 Steel Grit, 36 possibly also 3060 Mesh Garnet, 16 Grit Aluminum Oxide, 2050 or 1230 Copper Slag, 1240 Coal Slag

 

 

 

 

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Using Crushed Glass To Clean Precast Concrete

Crushed Bottle Glass Abrasive For Concrete

Armani Restoration Job SiteCrushed Bottle Glass Abrasive is used to clean and restore the exterior of this 27 story concrete building.  Using a proprietary wet and dry blasting system, the contractor dramatically changed the surface color of the building, as you can see in the photo.  The concrete surface of this building was not smooth – it did have a texture to it, so a medium grade was chosen.  The end result is a much brighter surface color to the concrete, without damaging the exterior.

Crushed glass sandblasting abrasive is the perfect choice for either light cleaning of precast concrete, or by using coarser grades, exposing the aggregate in the concrete.  A medium/fine grade was used for this job, as the customer did not want to damage the surface of the concrete.

Crushed bottle glass abrasive is a 100% recycled product, and is shipped from a variety of locations.  It contains no free silica, no heavy metals, is inert, and it blasts fast and clean.  Many times people will just leave it on the ground rather than clean it up (unless you are blasting off something toxic like lead paint or have local laws requiring cleanup).  This makes it great for blasting log homes and automobiles as it minimizes cleanup in areas where it can be left on the ground as a soil amendment.  Because this type of abrasive is shipped from all multiple points of origin, we will always try to find the closest location to your end job site when quoting.  NOTE:  If left on concrete it will be very slippery!

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Abrasive Grade Silicon Carbide – Uses Of

Silicon Carbide Grit

Silicon Carbide Grit & Powder

The main uses for abrasive grade Silicon Carbides (Carborundum) are:

Due to the very hard structure of silicon carbide (silicon + carbon) , it has historically been used as an abrasive.  Today, there are many high tech uses for varying grades of Silicon Carbide such as electronics, brake pads, ceramics, LED’s, diodes, transistors, semiconductive research, heating elements, even jewelry.  Gone are the days when Silicon Carbide was known only as an abrasive.

How Is It Made?  Silicon carbide is  manufactured by mixing silica sand (SiO2) and finely ground coke (carbon) together, then they are put into a brick lined electric furnace and baked at high temperature, while at the same time, an electric current is passed through a conductor.  This process can take days from start to finish, with the end result being chunks of silicon carbide of varying purity.   The aggregate is then sorted, crushed, and graded.

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Silicon Carbide – Historical Facts

Black Silicon Carbide Abrasive

Silicon Carbide Sandblasting Abrasive

Silicon Carbide (SiC) was the first synthetic abrasive to be produced and also the first to be commercialized.  1891 was the year that silicon carbide production began, and thus revolutionized the abrasive industry as a whole.  Before 1891, almost all abrasives were naturally found such as rocks and minerals.

By 1900 Silicon Carbide production was at 1,200 metric tons, carrying an estimated value of $263,000.  Mainly used in the lapidary industries, it was a replacement for diamond powder.  At that time, the only other manufactured abrasive was crushed steel and as a contrast in volume, crushed steel production was only 320 tons, carrying a rather paltry value of ~$50,000.

With exception only given to diamond and garnet, by the year 2000, manufactured abrasives dominated the high end abrasive industries.  Unlike natural abrasives, manufactured abrasives could be tightly controlled, thus ensuring uniform properties like hardness and grit size.  A further benefit was the ability to customize the manufacturing process to meet exact specified needs, based on the end application.  While being more expensive that natural abrasives, their durability and efficiency made them more cost effective overall.  They are therefore used heavily in the metal finishing, cutting, and polishing fields.

In short, manufactured abrasives are extensively used today in finishing numerous products.

 

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Boron Carbide Blast Nozzles – When To Use One

Short Answer: Use a boron carbide blast nozzle anytime you are using aluminum oxide or silicon carbide as your abrasive blasting media.

When To Use Boron Carbide Blast Nozzles
When To Use Boron Carbide Blast Nozzles

Long Answer:   The three most popular materials used today for blast nozzles are Tungsten Carbide, Boron Carbide, and Silicon Carbide.  Boron Carbide nozzles are the hardest of the three, followed by Silicon Carbide, and then by Tungsten Carbide.  Hardness is necessary to order to withstand the wear and tear that the blast nozzle liner will be exposed to by the abrasive used.

However, the greater the hardness, the more brittle the material.  This is why Boron Carbide nozzles need to be handled with care.  When we ship B4C blast nozzles, we use a lot of packaging material to ensure safe transit.  Never drop, throw, pound, or abuse a boron carbide nozzle or you will destroy it.  (Just because boron carbide is the hardest material you can buy, does not mean it is not brittle.)

 

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