Aluminum welding has long been a challenge for welders due to its unique properties and characteristics. Among the various welding techniques, stick welding or Shielded Metal Arc Welding (SMAW) is many welders' least favorite when it comes to aluminum welding. It is messy and can yield unpredictable rewards.
However, stick welding is still a viable aluminum welding method. So, in this article, we delve into the science of stick welding aluminum, uncovering the essential tips, tricks, and techniques that can transform this once-daunting task into a manageable and effective process.
Can You Stick Weld Aluminum?
The simple answer is yes, you can Stick weld aluminum, but... Stick welding is a small and largely unrecognized method for welding aluminum because it yields highly messy results. Aluminum is often chosen due to aesthetics, and you cannot achieve the same results with Stick/Arc as with TIG welding or pulsed MIG welding.
Additionally, stick welding is not suitable for thin aluminum. Stick welding with aluminum welding rods isn't generally recommended for metal under 1/8". Knowing that aluminum usually comes in thin sheets can represent an issue.
Nonetheless, suppose you don't have access to an AC TIG welder or Spool gun MIG welder. In that case, you can use your stick welding machine for occasional aluminum repairs and thick aluminum maintenance work. It can be used in remote jobs, maintenance, and repairs, but in fairly limited situations.
Why Is Aluminum So Difficult To Weld?
The challenge of aluminum welding comes from the very same characteristics that make it widely used in industries across the globe. The first challenge is caused by the aluminum oxide that forms once the aluminum surface is exposed to oxygen. This oxide gives aluminum its silver-gray look and makes it resistant to water, oxygen, and certain chemicals.
However, it has a different melting point than base aluminum. The oxide layer melts at 3,700°F (2,037°C), while pure aluminum underneath melts at 1,200°F (650°C). Therefore, if you try welding straight through the layer, you'll burn through the aluminum underneath.
Another issue comes from the thermal characteristics of the aluminum. The aluminum conducts heat five times faster than steel, so the heat you point into the welding joint quickly disperses. Therefore, you'll need a higher amperage to provide enough heat into the joint.
Now, things get even more complicated when it comes to stick welding. Stick welding is known for its low-cost, high-productivity approach, which makes it widely used in various industries across the globe. Welders use it when they need to get things done quickly and cheaply, typically on rusty or dirty metal, but you can do something other than aluminum. Aluminum requires proper preparation, reasonable heat control, and more experience so it can be a challenging task for many Stick welders.
However, stick welding aluminum can still be done in specific applications, so let's see how.
How To Stick Weld Aluminum
Stick welding aluminum can be a daunting task with unpredictable results, but if you do everything right, you can achieve satisfying results and sound welds. You'll need proper weld preparation, suitable welding equipment, cleaning time, and some practice put into welding technique. Even though you can't expect TIG-like results on aluminum with stacked dimes, you can create sounds and everlasting welds.
Aluminum Pieces Preparation
Before you actually start to stick weld aluminum, you'll need proper weld preparation. Due to the different melting points of aluminum and its oxide, you'll have to remove it prior to welding. To do so, you should use a dedicated stainless steel brush. The mild steel brush can contaminate the surface, so ensure you only have one brush for aluminum.
Remember that the oxide layer forms quickly after exposure to oxygen. Therefore, you shouldn't way too long before you start to weld. Also, avoid using grinders since they can blend the oxide layer thicker into aluminum rather than remove it.
Additionally, you'll need a proper piece fit-up. You don't want any excess gaps that will require more filler metal or anything that can interfere with the integrity of the weld.
Stick Electrode For Aluminum
To successfully stick weld aluminum, you'll need a proper rod. E4043 is a general-purpose aluminum electrode for arc welding aluminum alloys. The arc is stable and operates at low temperatures with minimal spatter and fuming. These electrodes come in various sizes, from 5/32" to 3/32", but you will commonly find them in a diameter of 1/8", which requires amperage of 80 to 135.
Depending on the manufacturer, these electrodes can be used in all positions or limited to flat, horizontal, and vertical applications. Most of them will require DCEP polarity, but some will work with DCEN, so make sure you check the requirements before purchasing.
While E4043 aluminum stick electrodes produce stable arc and low spatter, remember that they are pricier than regular steel electrodes. They also tend to burn fast, so you should be ready for higher costs. These electrodes are typically hygroscopic, which means they absorb water from their surroundings. So, if not stored correctly, the flux will become damp and gummy.
Check Your Stick Welder
Unlike other processes, Stick welding machine for aluminum usually doesn't need specific features or power options. You’ll only need to ensure that your welder has an adjustable amperage that fits the size of the electrode and the manufacturer's recommendations.
Machines such as YesWelder YWA-160 can handle various types of aluminum work. It has built-in features, such as hot start or arc force, that will help you deal with the high thermal conductivity of aluminum. Additionally, the high end of amperage is suitable for the high heat that aluminum requires.
Remember that you might need to experiment with welder settings until you get everything right. Stick welding aluminum is not such a common task, so you won't find online calculators as with steel. As a starting point, work with the manufacturer-recommended amperage found on the electrode package and work your way up to the best results.
Stick Aluminum Welding Technique
Due to the thermal properties of aluminum, the heat is quickly dissipated from the welding joint, so the weld puddle starts to solidify much quicker than steel. Therefore, you must maintain a short arc and go fast to stick weld aluminum successfully.
A travel speed that is too slow can cause two issues with aluminum. You can employ too much heat and burn through the pieces, or the puddle can solidify too quickly and cause the electrode to stick to the joint. However, if you go too fast, you might lack penetration and proper fusion, so if you are a beginner, you'll have to spend some time developing a perfect stick aluminum welding technique.
You commonly want to keep small and straight lines on thinner or medium-thickness aluminum. Weaving will cause a loss of required heat in the joint, leading to a lack of fusion and penetration, but it might be necessary for thicker pieces. Keep the tip close enough to feel the flux on the electrode dragging along the weld.
Finishing The Weld And Cleaning
Even though it is recommended to travel faster when stick welding aluminum, you should be careful when finishing the weld. If you run through the end of your aluminum weld, you may encounter a defect known as a weld crater. This defect occurs if you finish the weld too fast without waiting for the weld puddle to fill the end crater of the weld.
This issue is not only aesthetic. It presents a weak spot in your stick aluminum weld. This weak spot can cause cracking along the joint, so you should ensure the weld's end is filled correctly. If the crater has already formed, you should grind it slightly and rework it.
Finishing the aluminum stick weld will also require more cleaning compared to steel. Due to the nature of the flux and aluminum stick electrodes, you will have to spend some time cleaning the spatter and, of course, the slag layer on top of the weld. They will usually fall off easily, but the amount is significantly greater than mild steel welding.
Potential Issues When Stick Welding Aluminum
Now that you have finished and cleaned your stick aluminum weld, it is time for inspection. Most issues that occur when stick welding are easily notable, so you will only need a visual inspection to notice cracks, burn-through, or lack of fusion.
The most common issues that occur when stick welding aluminum are:
- Burn-through, warping, or distortion: If you try to stick weld thin aluminum sheets, there are great chances you'll encounter burn-through, warping, or distortion. Even though aluminum requires higher heat, excessive heat can quickly burn the holes in aluminum or cause distortion or warping on the surrounding pieces.
- Cracking: As the aluminum weld puddle solidifies, it can start craking depending on the specific aluminum alloy. The crack sensitivity of an aluminum base alloy is primarily dependent on its chemistry. However, with stick welding, this issue is more common due to the weld profile it creates, heat, and other aspects.
- Poor Weld Aesthetics: Besides its positive characteristics, many welders choose aluminum for aesthetics. With stick welding, you should expect rough and messy welds. Even though aesthetics are not strictly related to the physical and mechanical properties of the weld, you won't get stacked dimes like with TIG.
- Lack of fusion: Aluminum requires precise heat control due to thermal characteristics. If you provide too much heat, you can burn through the weld, but if it is too low, you'll get a lack of fusion. Since Stick welding doesn't provide heat control like pulsed TIG and MIG welding, it will take some time and practice until you get everything right.
- Weld Crater: As noted, this defect forms at the end of the weld, and it is expected if you run fast, which is required when you stick weld aluminum. Therefore, make sure you go quickly during the weld but spend appropriate time in the end to let the puddle fill the joint.
Alternatives to Stick Welding Aluminum
Even though Stick/Arc welding is a legit aluminum welding method, due to its drawbacks, most welders will choose MIG welding or TIG welding when it comes to aluminum joining. These two methods provide better heat control, higher cleanliness levels, aesthetics, and better results with thinner pieces.
MIG Welding Aluminum
Gas Metal Arc Welding, or MIG welding, is a semi-automated process that is known for its versatility and ease of use. MIG welding aluminum is favored among beginners since you can achieve decent results even if you are not an expert in welding. All you need is a spool gun or a unique liner that is capable of feeding the soft aluminum wire, and you'll be set for success.
In recent years, MIG welding machines such as YesWelder YWM-211P Double Pulse Welder introduced new features such as pulse and double pulse MIG welding. With double-pulse, you can achieve TIG-like welds with your MIG welder, and the best part is that you can do it without too much trouble.
Compared to Stick welding, MIG is much easier to use and produces higher-quality welds. The arc is more forgiving, and you get much better heat control. The advantage of stick welding over MIG is that you don't need shielding gas.
TIG Welding Aluminum
TIG welding is a go-to method for aluminum if you need high-quality, clean, professional, and aesthetically looking welds. The skill requirements are somewhat similar to Stick welding, so it is reserved for more seasoned welders. However, once you master TIG welding, you can achieve some of the highest-quality aluminum welds with TIG.
Compared to Stick, TIG welding will require fine-tuning and high-quality shielding gas. TIG welders must support AC current, and machines such as YesWelder 200P-AC/DC have various features and controls that allow the welder to control the heat and fine-tune the adjustments. Meanwhile, you can Stick weld with your basic welder and without some advanced features. However, the results on aluminum cannot be compared with Stick and TIG.
When Is A Stick Prefered Over MIG And TIG Welding Aluminum?
There are very few applications in which welders will use Stick welding to join aluminum pieces over MIG and TIG. Most commonly, Stick welding is prefered in:
- Outdoor and Remote Welding: Stick welding is more forgiving in windy or outdoor conditions where shielding gas for MIG or TIG may be disrupted. Welders working in remote locations with limited access to electricity and specialized equipment may opt for stick welding due to its portability.
- Thicker Aluminum Materials: Stick welding is better suited for thicker aluminum materials (typically 1/8 inch or thicker) because it can provide deeper penetration and faster travel speeds than TIG welding.
- Maintenance and Repair Work: Stick welding can be a go-to choice for on-site repairs and maintenance jobs. If you have a small repair project or repair work on thicker aluminum, you can quickly do it with your stick welder rather than employing more complex MIG or TIG equipment.
- Cost Considerations: Stick welding equipment is often more affordable than TIG and MIG setups, making it an attractive option for budget-conscious welders or hobbyists. However, keep in mind that aluminum electrodes are expensive and burn quickly. You might be surprised how much you spent just for a quick repair.
Stick welding aluminum is a valuable skill in a welder's toolkit, offering versatility in challenging situations. While it may not be the primary choice for most aluminum welding applications, it shines in scenarios where other methods might falter.
Its resilience in outdoor conditions, suitability for thicker materials, and cost-effectiveness make it an indispensable option for remote jobs, maintenance, and repairs. However, it requires practice and expertise to master, and welders should be aware of its limitations, especially when compared to TIG and MIG welding.
🧐Stick Welding Aluminum - FAQ
1.Why Is Aluminum So Difficult To Weld?
Aluminum welding presents challenges due to its protective oxide layer, which melts at a higher temperature than the pure aluminum beneath. This requires careful welding techniques to avoid burning through. Additionally, aluminum conducts heat much faster than steel, necessitating higher amperage. Stick welding, known for its cost-effectiveness, is trickier with aluminum, requiring precise preparation and heat control, making it a challenge for many welders.
2.What is MIG welding aluminum?
MIG welding, known for its versatility and user-friendliness, is a semi-automated process ideal for beginners, especially when welding aluminum. A spool gun or specialized liner for soft aluminum wire is crucial for success. Recent advancements, like the YesWelder YWM-211P Double Pulse Welder, offer features such as double-pulse MIG welding, allowing for TIG-like welds with ease. Compared to Stick welding, MIG provides better heat control and higher-quality welds, although Stick welding does not require shielding gas.
3.What is TIG welding aluminum?
TIG welding is the preferred method for achieving high-quality, clean, and professional aluminum welds. It requires a higher level of skill, making it suitable for experienced welders. Once mastered, TIG welding can produce some of the highest-quality aluminum welds. Compared to Stick welding, TIG requires precise adjustments and high-quality shielding gas. Welders using TIG must have machines that support AC current, like the YesWelder 200P-AC/DC, which offers various controls for heat and fine-tuning. While Stick welding can be done with basic equipment, the results on aluminum do not match the quality achievable with TIG.