Tungsten Inert Gas (TIG) welding is a process of welding that produces an arc in between the electrode and base metals. This technique uses shielding gas (helium or argon) to eliminate the chances of environmental contamination or oxidation, which flows parallel with the wire.
TIG welding offers greater control to welded during the operation than other welding techniques, including shielded metal arc welding (SMAW) and gas metal arc welding (GMAW), which results in strong and high-quality welds. But it is not really faster and tricky and challenging to master as well.
Moreover, this procedure is excellent for welding thin steel metal pieces and non-ferrous metals, including copper, magnesium, and aluminum. TIG welding is an ideal procedure for welding aluminum because it is a lightweight metal as compared to steel, but aluminum welding is very time-consuming. In this post, we’ll share with you some tips for TIG welding aluminum with DC.
TIG welding of aluminum is mostly done with alternating current or AC. But alternating current has a scrubbing effect on aluminum; that’s why weld quality is not always ideal. Moreover, the direct current or DC rig welding of aluminum is also possible. Sometimes this style of TIG weld aluminum is excellent.
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AC TIG vs DC TIG
The direct current TIG welding is ideal in those cases where the current is flowing in just one direction. Whereas the alternating current flows in both directions, that’s why it scrubs the surface of the metal workpiece. Moreover, the direct current doesn’t stop until the welding procedure comes to an end which is not the case with alternating current.
Alternating current circulates the polarity in between the electrode and metal workpiece. That’s why AC TIG welding is ideal for welding low melting point metals such as non-ferrous alloys. On the other hand, DC TIC generates an arc that goes deeper into the weld, making it excellent for welding thin steel workpieces and thick aluminum segments.
Why should you use direct current for TIG weld aluminum?
DC is preferable for TIG weld aluminum as AC TIG welding doesn’t penetrate deep into the fused point and hence creates a shallow weld. If you are going to weld pieces of aluminum that are thicker than 0.25 inches, then you can’t get a strong joint with AC in a single pass.
To create a strong weld while using alternating current TIG welding on thick aluminum pieces, you have to perform the steps. Moreover, you have to level the edges of the joint and then lay down the roof bead, and after that, apply one or more passes of filler and cap weld to produce the strong weld. In this way, the TIG welding of aluminum with AC requires 3 to 4 keys to get the work done.
On the other hand, you can produce a substantial and reliable joint with one pass using direct current. Furthermore, going for DC TIG vs. AC TIG saves your time and effort because tungsten inert gas welding requires the welder to use both hands while applying this technique which is very hard.
DC TIG welding is also excellent for fixing sharp pits and gouges in aluminum workpieces. Moreover, you can easily fill the holes in by this method; after the hole is filled, you now have to level the surface with a spatula. In this way, you can repair slightly damaged industrial aluminum machines inexpensively.
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What kind of aluminum is suitable for DC TIG welding?
Not all types of aluminum grade are suitable for direct current TIG welding. The grades of aluminum appropriate for this technique are 2219, 6061, and 100 percent original aluminum. AC TIG welding is undoubtedly excellent for all types of aluminum other than that.
Moreover, the thickness of the aluminum also matters; you must take this into account. DC welding is not suitable for welding aluminum workpieces with a thickness under 0.25 inches because it will cut these pieces due to the excessive amount of heat this technique bestows on them.
Related:
- How to setup TIG welder for mild steel
- Can you weld aluminum to steel by TIG welding?
- Best welding rod for cast iron
DC aluminum welding: Tools required
To create high-quality welds, you need to have proper tools for this job which includes:
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Rods
Rods are very important for DC TIG welding aluminum as we use them as filler metal. So, these rods must be of 100 percent pure aluminum; otherwise, the joint will not be as strong as the base metals are. 4043-grade aluminum rods are exceptional and create smooth beads. You can also employ 5356 aluminum-grade rods, but the joints look unaesthetic and rough. We advise you to don’t to ever use alloy metal rods.
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Electrode
Two percent lanthanum tungsten electrodes are very excellent to be used as electrodes in DC TIG welding for aluminum. A sharp tip on the electrode is necessary for TIG welds with DC. If you can sharpen the tip of electrodes easily at home, then fine otherwise, pre-sharpened electrodes are also available in the market. Besides, the 3/32 inch diameter electrodes are excellent as they can handle excessive heat better than standard 1/16 inch diameter electrodes.
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Gas
One hundred percent pure helium gas is an ideal shielding gas for DC welding, and it produces a hotter electric arc as compared to the mixture of helium & argon and pure argon. The hotter arc eliminates the oxide layer over the joint. The extra clean heat is the major difference between DC and TIG. Ensure that there should be no oxygen content in our pure helium gas cylinder because a little bit of its composition can contaminate the weld.
Setting up welder
You certainly need to set up the weld if you want to perform DC TIG welding. After that, you need to reverse the polarity of the welder. Then the electron is the +ve terminal, and the intersection point of two base metals will be the terminal point. Moreover, this reverse polarity generates the electric arc, which is very hot, so always ready to perform.
Variable amperage
Amperage controllers are a very important component of any TIG welding machine as It allows you to control the amperage. In this way, you’ll make flawless welds. However, within variable amperage, you’ll not be able to lower down the heat emerging from the electrode and can really damage the workpieces. It is so because until you are ready to go from one point of the weld from another point, you’ll see the weld fused already.
How to scrub an oxidized layer in the weld?
The stainless steel brush is an excellent tool to eliminate the oxide layer effectively. However, always use a fine bristled brush and only use it to scrub away the oxidized layer from aluminum. Please don’t use a brush other than these metals for scrubbing otherwise, you’ll worsen the welding process instead of bettering it. And take your time to clean the oxide layer while using the brush.
What is the procedure of direct current TIG welding aluminum?
The technique is the most important thing in every kind of welding, including direct current TIG welding aluminum as well. To meet the filler, metal workpiece, and setup requirements, you need to modify your work style. Below given are some useful tips that will help you perform DC TIG welding:
- Like other types of welding, wearing the safety clothes like leather gloves, welding boots, glasses, and a protective helmet because TIG is a gas welding process and gives extreme heat during operation
- Apply right cutting procedure: Plasma cutters and ultimate speed circular saws cut the fuse metal in an aesthetic way
- Moreover, always hold the welding/cutting torch at a 90° angle from the weld and keep its tip closer to the joint. This way, you can create high puddles and incredibly clean welds.
- You can gain more control over the welding procedure if you keep the electrode at an upright position
- You should be fast in the whole welding procedure to avoid metal warping. For this, you can change the amperage by the controller if it has
- The reverse polarity can change the electrode tip from sharp to round during the process due to the electric arc. If something like that happens to you, stop the machine and then sharpen the electrode first and then start the process
- To make a smooth and precise weld, hold the rod always flat. Place the rod at the center of the puddle in contact with the arc and then pull it back to get a strong joint.
Hope you enjoyed our tips for TIG welding aluminum with DC.
For any questions comment below.
