The MIG gun consumable that we are concentrating today on is the ‘nozzle’. You might have a variety of MIG gun nozzles designs and build-quality that provide the performance for your weld accordingly.
The main goal of purchasing a consumable is to delay or put off replacement time as much as possible. The purpose of a MIG gun nozzle is pretty straightforward, where you use it to direct the shielding gas into the weld puddle and also protect the contact tip from molten metal.
The major questions that arise in your mind which choosing a nozzle for your MIG gun can be – Which nozzle lasts longer? Is this nozzle the most-effective one? Am I paying the right price for the features that this nozzle is offering?
The best welding nozzle for the user will explicitly depend on the welding application, joint access, and process used. Moreover, the material of the nozzle you buy depends on the way you weld, either in spray, pulse, or short-circuit manner.
The commonly used material for MIG gun nozzles is copper, bronze, and sometimes with plated metals.
Copper welding nozzles are a good choice to protect your welding gear against spatter and it might be your only choice if you have a very high amperage used (>300 amps) and if the arc-on time is longer.
If you need resistance to even higher temperatures (>400 to 600 amps), heavy-duty copper nozzles have thicker walls and thicker insulation material used.
Brass welding nozzles is the best material used for nozzles for obtaining spatter-free welds. This nozzle is ideal for 100-300 amps being quite affordable. Brass helps us maintain the proper inner diameter of the nozzle for a very long period of time.
This results in a longer-lasting consumable. A chrome or nickel-based layered nozzle is much better than copper or brass in resisting spatter than the others along with increased durability.
Such nozzles having copper or brass coating on the outside and chrome or nickel coating on its inner-surface makes it a better choice with very good amounts of durability.
Threaded and Slip-on Nozzles
Your MIG gun can accommodate only one type of nozzle when we compare ‘threaded’ with ‘slip-on’ nozzle types. Both of these nozzles have a difference in the security and the speed of the connection of the nozzles.
Threaded nozzles have a very secure and strong connection with the welding torch which helps any sort of gas leakage. You will also obtain some good concentricity with the contact tip as these threaded nozzles never allow the nozzle to go off-center.
The only downside with a threaded nozzle is the difficulty in replacing or removing the nozzle if any sort of debris or spatter formation takes place in the nozzle. Slip-on welding nozzles take an upper hand in this scenario as they are easy and quick to remove and replace the nozzle when required.
They are very good for overhead welding applications because it produces a large amount of spatter and heat at the base of the MIG gun’s neck. Slip-on nozzles are lower-priced than threaded nozzles and also provide good amounts of durability to the MIG gun consumables.
Generally, a tension band is attached at the base of the MIG gun to secure the nozzle to the MIG gun properly and there are certain conditions where these rings can loosen up in no time leading to nozzle misplacement.
Conical Welding NozzlesThe conical-shaped nozzle gives us optimal gas coverage along with surplus visibility while doing manual welding. The shielding gas will cover a larger area near the puddle because of the inner conical shape and also accelerates the gas into the weld puddle helps to keep the weld from being affected by any sort of turbulence or harsh atmospheric conditions.
Conical welding nozzles are available in various sizes where the most common sizes are ½” and 5/8”. It is recommended to use these conical nozzles when welding with zinc or zinc-coated metals. Zinc produces a lot of spatter and explosive debris while welding. The clearance of the base of the MIG gun with the nozzle is quite more compared to other shapes making it use a two-stroke reaming process with some air-blast.
If you are using a 12mm inner diameter nozzle, you can safely use an 8mm outer diameter contact tip as we get a good amount of gas clearance to cover the weld approximately. If we use a contact tip of a larger size like M10 or M12, you can prevent poor gas coverage and risk porosity in your welds and spatter bridging.
Bottle-form Welding Nozzles
Bottle-form nozzles are nozzles having an outer diameter that becomes a smaller outer diameter on the work-end making it look like a ‘bottle’. They have good accessibility and visibility while welding. Bottle-form nozzles are efficiently used in robotic applications as it can be easily cleaned using torch cleaning stations in robotic applications.
Here the gas coverage is much smaller than that of the conical nozzle. Just like a cylindrical nozzle, the gas flow with bottle-form welding nozzles is highly impacted by atmospheric conditions. More and more the front-end of the nozzle is constricted around the tip and tip holder, it will experience faster spatter buildup.
There are some other types of nozzles like ‘Tapered’ nozzles which operate in a similar way to Bottle-form nozzle. The only difference is that it has a smaller bore size. They are extremely useful in applications like pipe welding or very tight corners.
Cylindrical Welding NozzlesCylindrical welding nozzles are also known as ‘Straight’ nozzles are nozzles used mainly for very high amperages and working with large contact tips like the M10 and M12 sizes. When you are using the M10 nozzle, you need to maintain an ideally good distance between the contact tip and the nozzle wall as much as possible. This is because you need to facilitate a good amount of airflow and accommodate the contact tip.
These nozzles offer the best nozzle reamer cleaning results around the tip and the tip adaptor and on the inner gas nozzles. The access to these nozzles is limited and also have limited contact tip selection types. M6 and M8 contact tips are not recommended with the cylindrical nozzles. These contact tips allow the excessive flow of shielding gas causing porosity in the weld produced.
|Welding Applications||Nozzle Considerations|
|Welding Current||Larger bore size of the nozzles must be used for higher temperatures. Standard duty nozzlesis ideal for low welding current applications to save money and some valuable time.|
|High Heat||Use a heavy-duty, copper nozzle for high temperature and amperage applications. Brass nozzles have good spattered resistance have more resistance towards manual damages than copper nozzles at medium and low heat applications. Brass loses its beneficial properties when the temperature is above 450 degrees Celsius (840 F).|
|Limited Weld Access||Using a long nozzle helps us save gas and also get sufficient gas coverage. However, if weld access is an issue, use a shorter nozzle.|
|Heavy Spatter Generation||If heavy spatter is expected (i.e. galvanized base metal), use a short nozzle with a larger bore size. Brass material is also a good choice.|
|Nozzle Cleaning Stations||When using robotic nozzle cleaning/reaming stations, using a straight bore nozzle is much more ideal to obtain the best cleaning performance and experience.|
Flush Welding Nozzles
If you have the habit of welding in short-circuit mode, then using a flush welding nozzle is the best choice. Hence, here we don’t find much of a wire stick-out that is excessive and provides a better view of you seeing the wire that is traveling wherever you weld. With better visibility, manual MIG welding is easy to do with a flush welding nozzle.
One of the only drawbacks with a flush nozzle is that you will be prone to spatter bridging as the contact tip will sit in-line with the bore of the welding nozzle. Using an anti-spatter solution and regular cleaning and maintenance is required to prevent the formation of spatter in the future.
In these types of nozzles, the contact tip protrudes out of the nozzle exit point to reach or touch the workpiece before the nozzle does so. This type of welding nozzle is to be used only if you have issues accessing your torch to your welding piece.
If you tend to weld in tight corners and deep down of a structure, then you need to use stick-out nozzles to access it. The stick-out nozzles have contact tips that are very open and hence do not have any sort of gas coverage at all.
Recessed NozzlesRecessed contact tips are intended to use with a longer wire stick-out. Generally, when we use a recessed welding nozzle wee need to be welding in spray or pulse mode and at higher amperage.
This is because the contact tip sits deep inside the nozzle and allows a greater gas coverage speculation when the recessed nozzle is used for MIG welding.
No matter whatever material, size, shape, and stick-out and type of nozzle you use, you yourself help increase the life-span of the nozzle and resist spatter by proper maintenance and using anti-spatter products.
Make sure you use quality anti-spatter solutions to increase the lifetime of your nozzles and also its replacement time.
Sean Coby is a welder par excellence and well respected among the welding community in Woodbridge, VA. He prides himself to be the fabricator and mechanic in the automotive/ diesel industry for the past more than eight years now. As the chief editor of his https://weldinginfocenter.com, he shares his experience to be safe during welding and to take proactive steps for becoming a successful welder like him.