Category Archives: Blast Nozzles

News and technical data on sandblasting nozzles.

Picking Grit Size For Sandblasting

How do you pick a grit size?

A quick and simple answer is to pick a maximum grain size that is about equal to the thickness of the coating being removed.  So if what you are trying to remove is 1.6 mm thick (.063 inch), you would choose a 12 grit.  A bit finer size is often used as well, because you get better coverage as the finer particles fil into grooves, cracks, voids in the surface that the larger particles will not fit into.

A more detailed answer involves selecting a grit size based on the surface profile you are attempting to achieve on your substrate.  A quick guide can be found here.

Keep in mind that the more rounded a particle is, the more contact area it has with your substrate, and this can speed up cleaning rates.  Glass bead is a good example of a cleaning abrasive, whereas the more angular and blocky aluminum oxide particle is useful for actual surface preparation.  (Where you want the abrasive to leave a surface profile for a future coating).

 

 

Share

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!

Share

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)

 

Share

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.)

 

Share
Schematic Drawing of a Venturi Nozzle

Venturi Sandblast Nozzles Vs Straight Bore Blast Nozzles

Schematic Drawing of a Venturi Nozzle

So what is the real difference between these two types of nozzles, and why should you care?  Well, for starters, you should know that the introduction of venturi nozzles over thrity years ago still remains the last major advance in nozzle technology.  Thirty years is a long time!

You see up until the mid 1950’s, all sandblasting nozzles were straight bore.  They had a tapered converging entry, a parallel throat section, and a full length straight bore and straight exit.  Over time, blast operators noticed that as the interior of these nozzles began to wear and erode away, a larger and more efficient blast pattern resulted.  This observation led to the development of the venturi design.

A long venturi nozzle is characterized by having a long tapered converging entry, with a short flat straight section, followed by a long diverging end which widens as you reach the exit end of the nozzle.  A long converging entry introduces the air and abrasive mix into the nozzle, then is constricted into a short flat straight section, and then forced out the flared exit end.  Venturi nozzles can increase productivity by as much as 70% due to the larger abrasive pattern that results as well as due to the increase in velocity of the abrasive as it exits the nozzle.  In fact, velocity (outlet speed) of the exiting abrasive can be nearly double that of a straight bore nozzle, and this is force that cleans a surface faster!

So if you are in the market looking to upgrade your operation, perhaps changing to a venturi nozzle might be a good place to start.  More on that later…

Share