Your abrasive blast nozzle is probably the second most important blasting item you will address after your air supply regardless of the type of equipment you are using. Choosing the right blast nozzle for each application is simply a matter of understanding the variables that affect cleaning performance and job costs. There are Four Basic questions to answer for optimum cost/performance.

1. What Blast pattern do you want?

A nozzle’s bore shape determines its blast pattern. Nozzles generally have either a straight bore or a restricted, venturi bore.

Straight Bore Nozzles create a tight blast pattern for spot blasting or blast cabinet work. These are best for smaller jobs such as parts cleaning, weld seam shaping, cleaning handrails, steps, grillwork or carving stone and other materials.

Venturi Bore Nozzles create a wide blast pattern and increase abrasive velocity as much as 100% for a given pressure. Venturi nozzles are the best choice for greater productivity when blasting larger surfaces. Long Venturi style Nozzles yield about a 40% increase in productivity compared to straight bore nozzle while abrasive consumption can be cut approximately 40%. The new XL Long Venturi Nozzles provide an even more increased abrasive velocity and production while maintaining a lightweight nozzle for the operator to hold.

The double venturi Style nozzle can be thought of as two nozzles in a series with a gap and holes in between to allow the insertion of atmospheric air into the downstream segment of the nozzle. The exit end is also wider than a conventional nozzle. Both modifications are made to increase the size of the blast pattern and minimize the loss of abrasive velocity.

Wide Throat nozzles (wide entry) feature a large entry throat and a large diverging exit bore. When matched with the same sized hose, they can provide a 15% increase in productivity over nozzles with a smaller throat. When wide throat nozzles also feature as larger diverging exit bore, they can be used at higher pressures to yield up to a 60% larger pattern with lower abrasive use.

It’s also a good idea to have angle nozzles, banana nozzles, fan nozzles and other specialty nozzles on hand for tight spots like bride lattice, behind flanges, or inside pipes. Why waste time waiting for the abrasive to ricochet to get the job done? Angle nozzles are available in 1, 2, or 3 outlets in both 45 or 90o Angles.

2. Can you air supply support the nozzle?

Your air supply should be able to provide 50% more air volume (cfm) than a new nozzle would need to develop the required working blasting pressure, whether that is 100 psi or 140 psi. This ensures a nozzle can continue to provide good service even after it is slightly worn.

Note: Productivity decreases dramatically if excessive wear happens... Also the nozzle entry throat must match the inside diameter of your air supply hose. The wrong size combo can lead to wear points, pressure drop and excessive internal turbulence.

Matching Nozzle Size and Compressor Size for Required Production Rate
Rate req. (sq. ft/hr) Blast Nozzle Orifice Production Rate @ 100 psi Nozzle Pressure Production Rate @ 90 psi nozzle pressure Production rate @ 80 psi nozzle pressure Compressor size CFM at 100 psi nozzle pressure
Up to 100 1/4” 100 85 70 185 cfm 40-50 h.p.
101-160 5/16” 160 136 112 250 cfm 60-75 h.p.
161-230 3/8” 230 195 161 375 cfm 75-100 h.p.
231-317 7/16” 317 270 222 450 cfm 125 h.p.
318-400 1/2” 400 340 280 600 cfm 150 h.p.
This chart is estimated and based upon use of a long venturi nozzle, SSPC-6 commercial blast specification

3. What Bore size do you need?

For maximum productivity, select the nozzle bore size based on the desired blast pressure and the available air pressure and flow. For example, assume you are running a 375 cfm compressor at 80% capacity. In addition to the blast cleaning nozzle the compressor is supplying air to an air fed helmet and other components such as air motors and pneumatic controls, leaving 250 cfm available for the nozzle. Referring to a nozzle air and pressure requirements chart, you can see that 250 cfm is sufficient for a 7/16” nozzle operating at 100 psi. A larger nozzle, or worn 7/16” nozzle will require more air flow to maintain 100 psi. This extra flow requirement will either overwork your compressor or decrease productivity. On the other hand, choosing a nozzle with a bore size smaller than your compressor can supply will result in less than maximum productivity from the system.

Also keep in mind that in order to supply the nozzle with the correct amount of air, the air line from the compressor to the pressure pot must be a minimum size depending on the nozzle size in order to deliver enough air. The bigger the nozzle, the larger the air supply line! Blast helmets and devices running off of compressed air will also ‘steal’ from your air supply so that must be taken into account.

Click here for the Air Requirements Chart which shows the amount of air required for nozzles

4. What are the best nozzle material choices?

Aluminum oxide (alumina) nozzles - offer good service life at a low cost compared to other materials. A good choice for low usage applications where price is a factor and wear is not.

Tungsten Carbide nozzles - offer long life and economy when rough handling can’t be avoided and mineral or slag abrasives are being used. Remember, All Tungsten Carbide nozzles are not equal.

Kennametal® SiAION Tungsten Composite nozzles - offers longer life than standard tungsten carbide nozzles. Very light weight (about 1/3 that of standard tungsten carbide nozzles) which reduces operator fatigue. Silicon Carbide Composite nozzles - offer service life and durability very near tungsten carbide nozzles but these nozzles are about 1/3 the weight of standard tungsten carbide nozzles.

Boron Carbide Nozzles - provide the longest life with optimum air and abrasive use. Boron Carbide nozzles is ideal and should be used with aggressive abrasives such as aluminum oxide, garnet, silicon carbide and selected mineral aggregates when rough handling can be avoided. Boron carbide will outlast tungsten carbide nozzles by 5 to 10 times and silicon carbide 2-3 times when aggressive medias are used.

Roctec® composite carbide nozzles provide even longer life than that of boron carbide nozzles and is ideal for applications with aluminum oxide and silicon carbide. Special angel nozzles, industrial gun inserts, etching nozzles, and pencil blast nozzles are a few of special types of nozzles available. Not all nozzle types are made in the Roctec® material.

Service Life Comparisons
Approximate Service life in Hours
Nozzle Material Sand/Slag Steel Grit/Shot Aluminum Oxide/Garnet
Aluminum Oxide 10-30 20-40 1-4
Tungsten Carbide 300-400 500-800 20-40
Silicon/Tungsten Composite 300-400 500-800 50-100
Boron Carbide 750-1500 1500-2500 200-1000
Roctec Longer than Boron Carbide Longer than Boron Carbide Longer than Boron Carbide
Estimated values for comparison. Actual service life will vary depending on blast pressure, media size and particle shape.

Increasing Productivity with Nozzles:

  • Regardless of the Nozzle used, maintain a consistent I.D. abrasive path from the blast pot to the blast nozzle. When using whip blast hoses, match the I.D. sizes so they are the same.
  • The airline size must correspond to the nozzle size used.
  • A 15% production increase can be achieved by using at least a 1-1/4” I.D. Abrasive path
  • A 1-1/4” wide entry Venturi Blast Nozzle (SN159 or Bazooka®) features a 25% larger entry port than a 1” entry nozzle, allowing the abrasive to flow smoothly into the nozzle.
  • 1” Entry nozzles should only be used with 1” I.D. blast hose or smaller.

Things to consider/provide to Metal Finishing when ordering:

1. What Manufacture and machine type is this nozzle used in? Any markings on the gun, nozzle or holder?

2. Application Type - Nozzle Type/Pattern (venturi, straight bore, wide entry, angle, etc...)

3. Bore Size of the Nozzle

4. Thread Type of Nozzle - 1-1/4” Fine Threaded, 50 MM Contractor Coarse Thread, Flanged/Tapered, Insert

5. Material Type of Nozzle - Aluminum Oxide, Tungsten or Boron Carbide, Tungsten or Silicon Composite

6. Nozzle Washer - Nozzle washers should always be used and changed/checked frequently. A good nozzle washer prevents premature wear on the nozzle holder and nozzle.

Types of Nozzles:

There are many other nozzles not listed that we can supply for all applications. Nozzles can also be custom designed when necessary for your machine or application.

Nozzle or gun inserts are typically found/used in suction guns in suction blast cabinet applications. They can be of different sizes and shapes, round or flanged and are typically straight bore nozzles. Available in ceramic, tungsten carbide or boron carbide materials. ¼” -1/2” bore available. ALC, Clemco/Zero®, Empire, Trinco™, Kelco typically fall under this category.

Made of premium grade alumina ceramic, tungsten carbide or boron carbide, these nozzles are typically used for small capacity abrasive blasting pots and are ideal for monument engraving, auto restoration, glass etching, and decorative artwork. Taper nozzles are held in usually by a nozzle nut (collar) are available in two styles, with multiple orifice sizes to choose from.

3/32”-3/8” available bore sizes. Ruemelin, Norbide®, Trinco™, PK Lindsay typically fall under this category.

A compact straight bore tungsten carbide or boron carbide liner with an aluminum or steel jacket is perfect for precision blasting at 12” or less. Typical applications for this nozzle include abrasive blast cabinets and internal pipe blasting. Also used for small blast hose applications. Available bore sizes are 1/16” – ½” and typically found with a ¾” NPS thread or a longer jacket style with 1-1/4” NPS Thread.

A durable tungsten carbide liner in a compact, impact absorbing jacket makes this ideal for use in tight spaces. At 12”-18” from the work surface, this nozzle produces the same blast pattern as a long venturi nozzle at 24”-36”. Typical applications are interior of pipes, bulkheads in ships, bridge lattice, and other tight spaces. Aluminum or Polyurethane Jacket and metal or polyurethane 1-1/4” NPS or 50 MM threads. 3/16”-3/4” bore sizes available.

Available in a Tungsten, SiAION or Boron Carbide liner, a Metal or Polyurethane jacket and 1-1/4” NPS or 50MM brass or polyurethane threads. Typically used with 1” or 1-1/4” ID blast hoses in blast rooms, blast yards, bridges, offshore platforms, oil refineries, pipelines, railcar shops, shipyards, storage tanks and water towers.

Featured Product:

Kennametal BP200 SiAION Long Venturi Nozzles

  • SN156-3AP/SN156-350AP – 3/16” orifice, All Polyurethane, 1” entry
  • SN156-4AP/SN156-450AP – 1/4” orifice, All Polyurethane, 1” entry
  • SN159-5AP/SN159-550AP – 5/16” orifice, All Polyurethane, 1-1/4” entry
  • SN159-6AP/SN159-650AP – 3/8” orifice, All Polyurethane, 1-1/4” entry
  • SN159-7AP/SN159-750AP – 7/16” orifice, All Polyurethane, 1-1/4” entry
  • SN159-8AP/SN159-850AP – 1/2” orifice, All Polyurethane, 1-1/4” entry
  • SN159-1050AP – 5/8” orifice, All Polyurethane, 1-1/4” entry
  • SN159-1250AP – 3/4” orifice, All Polyurethane, 1-1/4” entry

A unique tungsten carbide liner shape and aluminum jacket provides a larger blast pattern than a single venturi with a minor reduction in abrasive velocity. The double venturi design maintains an even distribution of abrasive particles throughout the larger blast pattern. Typical applications include blast rooms, blast yards, bridges, offshore platforms, oil refineries, pipelines, railcar shops, shipyards, storage tanks, and water towers. ¼” – ¾” bore sizes.

The XL Venturi Nozzles increase particle velocity resulting in improved production rates and efficiencies. It uses the same air as the standard long venturi nozzles but result in a lower compressed air operating cost per square foot. Light weight, ¼”, 3/8” or ½” bore sizes in 1-1/4” or 50 mm thd.

The Square Shooter nozzle production rate is faster than the conventional long venturi rate due to only a 10-20% overlap needed in the blast pattern. Less abrasive consumption as well as productivity savings will be achieved. ¼”, 5/16” or 3/8” bore sizes.

The Bazooka nozzle yields a 60% larger pattern with minimal operator fatigue when partnered with the same size blast hose and a 15% increase in production. ¼”, 3/8”, 7/16, ½” or ¾” bore

Angle nozzles provide an excellent opportunity to get inside tight places like bridge lattice, behind flanges or inside pipe. Available in Tungsten, Boron Carbide or Roctec® from 0o to 125o relative to the input openings. Available with single, double, triple or quadruple outlets and reverse angle outlets! ¾” NPS, 1-1/4” NPS or 50MM Thd available.

A boron carbide liner and uniquely shaped aluminum jacket make this nozzle perfect for more precise blasting in tight spaces. The design provides the flexibility to directly target hard to reach areas rather than blasting indirectly with rebounding abrasive.

Fan Nozzles are a Venturi Style Nozzle that allows the blast pattern to fan out to achieve a greater cleaning area. Typical applications include soda blasting operations including graffiti removal and soot cleaning.

The WIN® is a simple solution for high production, wet abrasive blasting that can be used with your existing pressure blast equipment. Requiring only 3/4 to 6 quarts per minute, water consumption is lower than most other wet blast options. Typical applications include dust-sensitive areas.

Testing Equipment:

Nozzle Gauge: An instrument for testing the bore size of the nozzle. Remove the nozzle from the blast hose, color using the graphite pencil on the tool and then insert the tool in the nozzles back entrance to measure the bore size. When the nozzle bore has worn 1-2 (1/16”-1/8”) sizes larger than that starting bore size, it’s time to change the nozzle. Every 1/16” worn requires approximately two times the amount of air you are currently using.

Hose/Nozzle Pressure Gauge: An effective means of measuring the blast pressure at the nozzle. Insert the gauge with the hypodermic needle into the blast hose at about 1” from the nozzle holder at a 45o angle. Always inset towards the nozzle with the abrasive stream. Measures the blast pressure you are getting at the nozzle!

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