When it comes to MIG or flux-cored (FCAW) welding on the jobsite, selecting the right gun for the application and following some basic maintenance and preparation tips can help make guns and consumables last.
RIGHT GUN FOR THE APPLICATION
Welding guns often take a lot of abuse on jobsites and in job shops, so it’s important to look for a durable gun that meets the demands of a specific application. Variables to keep in mind when selecting the gun include the material type and thickness to be welded, and how much welding will be required (if welding makes up 1 hour versus 7 hours of each workday, for example).
Additional challenges on outdoor jobsites are weather and wind, which can blow the shielding gas away from the weld puddle, causing porosity in the completed weld. For this reason, a popular option for many outside contractors is a flux-cored welding gun, which can be used with self-shielded wire that generates its own shielding gas to reduce problems caused by wind.
Whether using a MIG gun or a flux-cored gun, it’s important to select a gun with a rigid strain relief. A good strain relief (which refers to the connection between the power cable and power pin) helps to minimize kinking, which can lead to poor wire feeding, an unstable arc, and poor weld quality. Some additional issues to consider when selecting a gun include:
- The gun should have enough amperage to meet the needs of the application. To determine the necessary amperage, consider the material type and thickness and wire size being used.
- The power cable must have enough copper content to handle the amperage that will be put through it. When possible, use shorter power cables on the MIG gun to minimize costs and downtime further.
- The handle of the gun often is what takes the most abuse, so make sure to select a handle durable enough for the application, as some handles are designed for more light-duty applications. Choose a handle that is comfortable for the welding operator, and consider using the smallest handle that can still meet amperage needs.
- MIG gun triggers come in various styles and designs, such as standard, locking, and dual schedule, and selecting the trigger often comes down to operator preference. Select a trigger that’s comfortable to use and easy to access for servicing. Some applications may be well suited for a dual-pull trigger, which allows the operator to easily switch between settings without stopping and walking back to the power source to make changes.
MAINTAINING THE GUN
Regularly inspecting the MIG gun can be an important part of reducing costs and ensuring good welding performance, impacting productivity and efficiency. Preventive maintenance for MIG guns and flux-cored guns doesn’t have to be time-consuming or difficult. Often, the fundamental principles are the same, whether the welding is being done on a jobsite outside or in a shop. Here are some key tips for maintaining a welding gun on the jobsite:
- Make sure all connections are tight. Inspect the connections between the contact tip, gas diffuser, nozzle, and power pin. The wire feeder connection (where the power pin plugs into the feeder) must be tightened properly and should be free of dirt and debris. Loose or dirty wire feeder connections can cause heat to build up, leading to voltage drops that adversely affect the welding arc and may cause premature gun failure. Tighten the connection according to the manufacturer’s specifications or replace the direct plug if necessary to obtain a secure fit.
- Properly care for the gun liner. Make sure to install only a clean gun liner. Dragging a liner through the dirt while installing it can allow dirt and debris to accumulate on it, causing wire feeding issues. Having the proper cut length on the liner is also extremely important to help prevent bird nesting. It’s not uncommon during the course of welding for the gun liner to become clogged with debris. Spraying compressed air through the liner can help clear out potential blockages.
- Visually inspect the power cable. Look for any damage, such as nicks or cuts, in the power cable, which can affect wire feeding or conductivity. Power cable maintenance is an important part of eliminating unnecessary equipment costs and improving jobsite safety.
- Inspect the handle and trigger. Typically these components require little maintenance beyond visual inspection, but regularly look for cracks on the handle or missing screws. Check that the gun trigger is not sticking or otherwise malfunctioning, and replace these components as necessary.
- Check the gun neck. Loose connections at either end of the neck can cause electrical resistance that leads to poor weld quality and/or consumable failures. Also, visually inspect the insulators on the neck and replace them if damaged. These insulators prevent electrically live components from exposure, ensuring operator safety and longevity of equipment.
- Be mindful of consumables. Frequently inspect the nozzle and contact tip for spatter buildup, which can obstruct shielding gas flow and cause weld defects that will need to be reworked, costing time and money. Spatter buildup also can cause consumables to fail prematurely. Replace the nozzle and contact tip when necessary.
- Store the gun and consumables properly. Welding equipment performs best when it’s properly stored, such as in a box or cabinet, and kept out of the elements. Liners can become corroded from exposure to the environment, which impacts the conductivity and performance of the gun.
Regular and basic care and maintenance can help extend welding equipment life on a jobsite. Simple steps such as ensuring all connections are tight and in good working order and that the weld ground is good can help produce results every day. ■
About The Author
Mark Teach is a field technical support specialist with Bernard. For more information, visit www.bernardwelds.com.
Modern Contractor Solutions, December 2014
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