Selecting a Blast Nozzle - it’s as easy as 1, 2, 3

Elcometer’s range of high performance blast nozzles are both rugged and lightweight and are designed to minimise operator fatigue.

1. Choose Your Nozzle Bore Size

For maximum productivity, select the nozzle bore size from the table below, based on the desired blast pressure, available air pressure and volume of air flow. Elcometer supply a wide range of nozzle orifice sizes from 3.2mm (1/8") to 19mm (3/4") internal diameter.

Nozzle Bore Size

Using a larger nozzle orifice size produces a greater blast coverage area but requires a greater air capacity (cfm or m3/min) to ‘power’ the nozzle. A smaller nozzle size will typically produce a narrower blast pattern and consume less air. To maximise the potential benefits of using a larger nozzle diameter it is essential to ‘supply’ the nozzle with the correct air & media mix at sufficient speed and pressure. The choice of nozzle is therefore determined by the available air flow produced by the compressor. If a larger nozzle is chosen then to blast efficiently, a higher air capacity is required.

The table below shows the correlation between volume of air, nozzle size and nozzle pressure and is often used in the industry to select nozzle size. Its real benefit is to select the optimum nozzle size for the nozzle pressure required to carry out the job. If the user requires a nozzle pressure of 100psi (6.89bar) for optimum blasting and is using a ½” #8 nozzle diameter then they would need a 340cfm (9.63m3/min) rated compressor. If a 222cfm compressor was used then the resultant nozzle pressure using the same #8 nozzle would be reduced from 100psi to 60psi (4.14bar), meaning the blast efficiency would be reduced by 50%.


Nozzle Pressure psi (bar) Nozzle Size & Orifice
Diameter
Volume of Air - cfm (m³/min) 50 60 70 80 90 100 125 150
(3.45) (4.14) (4.83) (5.52) (6.21) (6.89) (8.62) (10.34)
12 13 15 17 19 21 25 29 #2
(0.34) (0.37) (0.42) (0.48) (0.54) (0.59) (0.71) (0.82) 3.2mm - 1/8"
25 30 34 38 42 46 56 67 #3
(0.71) (0.85) (0.96) (1.10) (1.19) (1.30) (1.59) (1.90) 4.8mm - 3/16"
47 54 61 68 75 81 98 115 #4
(1.33) (1.53) (1.73) (1.93) (2.12) (2.30) (2.77) (3.26) 6.35mm - 1/4"
76 89 101 114 126 138 169 200 #5
(2.15) (2.52) (2.86) (3.22) (3.56) (3.90) (4.78) (5.66) 8mm 5/16"
107 125 143 161 179 197 242 287 #6
(3.02) (3.54) (4.04) (4.55) (5.06) (5.57) (6.85) (8.12) 9.5mm - 3/8"
149 171 193 215 237 259 314 369 #7
(4.21) (4.84) (5.46) (6.09) (6.71) (7.33) (8.89) (10.44) 11mm - 7/16"
193 222 252 281 310 340 412 485 #8
(5.46) (6.28) (7.13) (7.95) (8.77) (9.63) (11.66) (13.73) 12.5mm - 1/2"
305 353 401 449 497 545 665 785 #10
(8.63) (9.99) (11.35) (12.71) (14.07) (15.43) (18.83) (22.22) 16mm - 5/8"
401 488 574 661 747 833 1050 1266 #12
(11.35) (13.81) (16.25) (18.71) (21.15) (23.58) (29.73) (35.84) 19mm - 3/4"

















2. Choose Your Thread, Jacket and Lining

Once you have determined the nozzle size, you now need to choose the material of the bore lining inside the nozzle and the material of the jacket protecting the bore. You also need to consider which style of thread best suits your needs; fine thread or contractor thread.

Nozzle Jacket

Acetal Jacket: Elcometer’s acetal jackets are lightweight whilst still providing impact protection.

Aluminium Jacket: Elcometer’s aluminium jackets offer a very high level of protection against impact damage.

Threads

Contractor Thread 51mm (2") Thread

The contractor thread has become the industry standard, at 4½ threads per inch (TPI), this style greatly reduces the chance of cross threading and is much easier to attach than a fine thread. Contractor threads are safer at high pressures and reduces chance of binding/galling.

Fine Thread 19mm (3/4") Thread

Fine threads are typically used on smaller diameter hoses and are used with the Elcometer 1020 Abrasive Blast Machine.

Bore Lining

Tungsten Carbide: The least durable of the carbide nozzles, but relatively inexpensive & resistant to impact. Ideal for areas when rough handling can’t be avoided and mineral, glass or coal slag abrasives are being used.

Silicon Carbide: Impact resistant and durable, like tungsten carbide, but approximately one-third of the weight, causing less operator strain. Ideal for jobs that require long periods of blasting.

Silicon Nitride: Silicon Nitride has outstanding wear resistant properties and as it is up to 50% lighter than other nozzles of the same size, can significantly reduce operator fatigue.

Boron Carbide: Extremely hard wearing, durable and up to ten times the longevity of tungsten carbide. Ideal for aggressive abrasives.

 

Nozzle Service Life in Hours

 

Replacing Your Blast Nozzle

A small increase in the nozzle size will result in a very large increase in air and abrasive consumption and adversely affect blasting efficiency. To ensure your nozzle provides continuous high production, as a general rule, replace your nozzle when the orifice wears by 1 nozzle size, when a #2 nozzle becomes the size of a #3 nozzle, for example.

The Elcometer 103 Blast Nozzle Gauge can accurately and easily measure your blast nozzle’s orifice size.

 

3. Choose Your Bore Shape

In order to achieve maximum blast performance it is important to choose the correct bore shape for your application. A nozzle’s bore shape determines its blast pattern. Nozzles come in two basic shapes: straight bore and Venturi bore, with several variations of Venturi bore nozzles available.

 

Straight Bore Nozzles:

Straight bore nozzles create a tight blast pattern for spot blasting or blast cabinet work. Ideal for smaller jobs such as parts cleaning, weld seam shaping, cleaning handrails, steps, grillwork or carving stone and other materials.

Venturi Bore Nozzles:

Featuring a converging entry and a diverging exit, Venturi nozzles create a wide blast pattern and increase abrasive velocity. Venturi nozzles are ideal for greater productivity when blasting larger surfaces.

As well as the standard straight and Venturi nozzles, Elcometer also supply double Venturi nozzles, angled nozzles and nozzles with water jet systems, to suit your specific application.

Double Venturi:

Featuring a wide exit opening with holes at the diverging end to allow the insertion of atmospheric air into the downstream segment, increasing the size of the blast pattern and abrasive velocity.

Angled Nozzles:

Angled blast nozzles are ideal for when blasting is required inside pipes, behind ledges, flanges of beams, inside cavities or other hard-to-reach places.

Water Jet System:

The water jet system mixes water with the abrasive inside a chamber within the jacket, reducing the amount of dust placed into the atmosphere. Ideal for harder abrasives when dust control is needed.