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Home TIG Welding How to Solve These 10 Common TIG Welding Problems

How to Solve These 10 Common TIG Welding Problems

by Steve Darnell
TIG welding problems

Learning how to TIG weld properly takes time and practice. The process is more complex and difficult to learn than other welding processes. If you’re just starting out, you’ve likely made some of the mistakes common to every new TIG welder.

Fortunately, this article will help you solve some of these common problems and improve your TIG welding skills. Here are 10 common TIG welding mistakes that beginners make and how you can avoid them.

10 Common TIG Welding Problems and How to Avoid Them

  1. Stained and Dirty Looking Welds

Make sure you clean your materials before you start TIG welding. This is a day one lesson every new TIG welder should have learned. It doesn’t matter if you’re working with mild steel, aluminum, or something else entirely—clean your materials. 

Things like mill scale, dirt and grease, or a layer of oxide on aluminum materials can easily contaminate your welds. Not only does this affect the appearance of the weld, but also the quality. A contaminated weld is more likely to crack or break.

The easy way to solve this problem is to slow down and make sure you dedicate time to prepping your materials. You should make sure to brush, grind, or wipe away the area around where you’ll be welding. 

Don’t forget to clean and prep your filler materials as well. If you’re reusing a filler rod, clean or cut the end of it to ensure there are no contaminants leftover from your previous work.

One last thing to note here if you ever work with aluminum. This type of metal is quite susceptible to contamination. This can easily happen if you clean a piece of aluminum with the same wire brush or grinder that you use on other materials like mild steel. When you’re working with aluminum, you should always have a dedicated wire brush and grinding wheel that is only used on aluminum.

  1. Craters and Cracks

Do you ever find yourself laying what you think is going to be the perfect bead until you see some cracking or a big crater in the center of it? This happens to a lot of beginners when they’re first learning how to TIG weld. 

There are two ways that this can happen. You either removed the filler rod too quickly at the end of the weld, or you cut the arc off too quickly. 

When you reduce the arc too quickly, the weld pool cools much faster than it’s supposed to and causes a crater to form. Once the crater forms, there’s likely going to be some cracks forming around the weld as well.

Fortunately, there are easy fixes to both of these problems. To stop crater cracking issues, make sure you continue to feed the filler rod as you slowly reduce the current at the end of the weld. If you gently ease off both the filler rod and arc as the weld is completed, the weld puddle can properly cool and form a quality weld.

One way to make this easier is to get a welding machine with a crater control function. Some machines will have a function that automatically reduces the current at the completion of the weld. Another option is to get a torch with a control button on it. Some torches have a button you can press to gently control and reduce the current as you work. 

  1. Using Too Much Amperage With Aluminum

Using the correct amperage is very important when you’re welding aluminum. Compared to mild steel, aluminum has a considerably lower melting point. It’s easy to have your machine set too high for the aluminum you’re working with. When this happens, you see a wider bead that doesn’t look clean or well-defined. You might even cause burn-through to happen if the workpiece overheats.

The easiest way to stop this from happening is to lower your amperage. Your machine may include a reference chart that tells you how many amps to set it to based on the aluminum’s thickness. If it doesn’t, there are plenty of charts online that you can easily reference as well.

If you think you have the amperage set correctly or lower it and are still having problems, it might be your travel speed. If the amperage is set correctly but your travel speed is too slow, you can still cause burn-through and wider welds. If that’s the case for you, simply increase your travel speed as you weld.

  1. Using The Wrong Polarity To Weld Aluminum

If you have a multi-process welding machine, it’s easy to forget to change the polarity to an alternating current (AC) instead of a direct current (DC). When the machine is set up with a direct current electrode negative, you won’t be able to break down the aluminum’s oxide layer and create a weld that’s part filler rod and partially melted oxide. Needless to say, that’s not a good weld.

You should always make sure that your machine is set up to weld with an alternating current electrode positive. This two-step cycle will allow the electrode positive portion to clean the oxide layer while the electrode negative portion melts the base metal. A lot of newer machines today will include a balance control to adjust the electrode positive to electrode negative ratio.

  1. Poor Arc Length Control

Sometimes you may notice that a weld’s bead has a change in color. If you notice the bead starts to look a little golden or brownish, you may have poor control over the length of the arc. The change in color you see is the result of the arc length increasing. The arc length is the distance between the electrode and the base metal and ultimately determines the voltage of the weld. If you end up holding too long of an arc, you can increase the overall heat input and cause distortion or a wider bead with less penetration into the base metal.

To stop this from happening, you need to practice arc control. It might take some time, but learning how to hold a consistent arc length can really improve the quality of your weld bead and heat input.

  1. Poor Shielding Gas Coverage and Contamination

Shielding gas plays an important role in TIG welding. Without shielding gas, oxygen and other airborne contaminants can negatively impact the quality and integrity of a weld. If you notice contamination around your welds, your shielding gas may be the culprit. Too much, too little, or the wrong type of gas entirely can all cause weld contamination.

To diagnose the problem, start by using the right type of shielding gas. For most TIG welding projects, 100% argon is the way to go. If you’re working with a thick aluminum, a blend of argon and helium can get the job done. Be careful not to use an argon and carbon dioxide mix like you would if you were MIG welding. This will cause immediate weld contamination. 

Just because your machine can switch between MIG and TIG welding processes, it doesn’t mean you can use the same shielding gas as well.

If the type of shielding gas isn’t causing contamination around the weld, there could be either too much or too little of it. Start by checking that you’re using the correct gas flow rate. For most projects, stick to a gas flow rate of 15 to 20 cubic feet per hour.

Next, you’ll want to check your hoses and fittings for any leaks. This can be done by wiping some soapy water around the hose and fittings. If there is a leak, you’ll be able to find it by looking for the bubbles. When you find the leak, you’ll need to replace that part to ensure you aren’t wasting any more shielding gas.

If everything checks out, but you’re still experiencing weld contamination, there might be a problem with the tank itself. While not that common, some tanks can get contaminated with moisture. If you suspect this has happened, you’ll need to get in touch with your gas supplier to swap out your bottle.

  1. Grainy-looking Welds

You can have the proper shielding gas coverage, correct amperage and polarity, properly cleaned materials, and still end up with grainy-looking welds. If this is happening to you, it might not be your technique or machine, but the type of filler rod being used.

Grainy-looking beads are typically caused by problems with the filler metal. This could be from dirt, grease, and other contaminants present on the tips of the rod. 

Some rods may have too much of a certain ingredient and be defective. Or, you could just be using the wrong type of filler rod altogether. Before you start any TIG welding project, make sure you check to see if you’re using the right type of filler rod for the job.

  1. Poor T-joint Fusion

When you’re completing a t-joint or fillet weld, you might be experiencing little to no fusion at the root of the joint. Again, this is something that a lot of inexperienced TIG welders will go through. Some of the most common reasons are an improper fit-up between the two pieces, incorrectly feeding the filler rod, or an arc length that is too long.

All three of these problems are easy to resolve. If the fit isn’t right, spend some more time prepping the materials until the joint is seamless. If the filler rod is being fed right, watch some training videos and spend time practicing. Last but not least, if the arc length is too long, try and hold the electrode closer to the joint. Reducing your arc length will help you have better direction control and get better penetration. 

You may want to consider investing in an inverter-based machine with advanced output controls. This type of TIG welding machine includes pulsing and frequency controls so you can create a more focused arc cone.

  1. Sugaring and Stainless Steel

If your weld is exposed to oxygen in the air, it can cause sugaring to happen around the weld. This causes a brown and grey ring to form around the backside weld bead on stainless steel. The sugaring is actually oxidation. It weakens the stainless steel and can lead to cracking and corrosion. 

To stop sugaring from happening around your stainless steel welds, you’ll need to do two things. The first is to reduce the level of amperage that you’re welding with. Next, you’ll want to back purge the weld with argon shielding gas. Doing both of these should resolve your sugaring problems when working with stainless steel. 

  1. Stainless Steel Discoloration

Sugaring isn’t the only way to cause discoloration around a stainless steel weld. Discoloration can easily be caused by overheating. 

Overheating happens when the amperage is too high, the travel speed is too slow, or the arc length is too great. The easy way to solve this problem is by decreasing the arc length, lowering the amperage, and increasing your travel speed.

The first step is easy. Adjust the controls on the machine, and the amperage is lowered. Learning to shorten the arc length and increase your travel speed takes practice though. If you want to get really good at TIG welding stainless steel, you’ll need to practice to learn how quickly you need to move your hands as you weld with control. 

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