How to Weld Aluminum with a Spool Gun? Weldlover Guide

There is the widespread use of aluminum alloy as a raw material for creating various products. Do you know that aluminum use ranges from the production of household items to aerospace manufacturing? Thus, it is obvious that aluminum welding is a demanding job these days due to its predominant use.

You may wonder why aluminum takes precedence in creating various commodities around us. Aluminum is extremely lightweight, anti-corrosive, and very resistant, making it a quality fabrication material. Despite these advantages of aluminum, it is one of the toughest metals to weld because of its complex properties.


Why is aluminum welding so complicated?

Welding aluminum with aluminum may not be a problem for most expert welders, but welding with iron is not that simple. It’s because of the different melting points of iron and aluminum, making it tough to handle molten aluminum while welding due to its low melting point.

Moreover, the direct welding of aluminum with iron or steel creates brittle intermetallic compounds in the weld, making it unreliable and weak. But if you are going to weld aluminum with iron, you have to adjust your welding machine so that it’ll not burn aluminum. So you must be very careful in this instance.

Besides, aluminum wire is very soft; that’s why it can easily break or burn while welding. Therefore, pro welders use spool guns for this job. However, if you want to learn how to weld aluminum with a spool gun, then proceed with reading.


Spool Gun: An Overview

What is a spool gun? It is a prevalent question of the majority of newbie welders who have to weld aluminum perfectly. Generally, a spool gun is a type of welder in the form of a gun which contains a spool. There you might be thinking, what spool is? It is a filler metal that usually weighs 1lb and has 4 inches of diameter.

Spool gun welding is preferred by skilled welders when they have to weld aluminum, especially when the diameter of aluminum is small. Do you know the major advantage of using a spool gun welder for welding aluminum? It’s excellent to feed thin and soft aluminum because the distance between the tip of it and the wire is less than 1 foot.

Like MIG welding, spool gun welding is very convenient and easy. That’s why welders learn aluminum welding with spool guns in no time. Moreover, it’ll be very economical for you if you’ve to shuffle between aluminum and steel welding repeatedly.

Spool gun vs. MIG welder for welding aluminum?

As discussed before, the main advantage of a spool gun is you can feed thin wire over a short distance which is 1 foot or less than it. On the other hand, MIG welding aluminum is practically not suitable as the liners are usually 7 to 8 feet long. Moreover, it isn’t easy to weld aluminum with a MIG setup. As you have to use both hands in this technique which requires a lot of time to master.

But in spool gun welding, you don’t need to worry about using both your hands at a time because 1lbs of the spool (filler aluminum wire) is preloaded in the gun. In this way, you can weld thin aluminum wire with ultimate productivity. Besides, the spool gun welder requires less skill to use it rather than a traditional MIG welder making it efficient for both hobbyists and professionals.

Some changes you have to make in your conventional MIG for aluminum welding

You’ve to modify your welding machine because aluminum welding is a lot different than steel welding. It is because of the incomparable physical and chemical properties of both these metals. Here are the modifications you are required to make to a welder

Dive Rolls

If you have experience welding steel, you will undoubtedly use a v-shaped groove in the dive rolls. But if you have to weld aluminum, then you should use a u-shaped groove in the dive rolls. You may be wondering why to replace a u-shaped groove with a v-shaped groove in dive rolls while aluminum welding.

There aren’t any sharp edges in a u-shaped groove like v-shaped grooves. By doing so, you can eliminate the risk of shaving or weeding aluminum. Moreover, it is suggested that you must reduce the tension on the dive rolls because aluminum is soft to handle that tension while feeding.


Do you know steel welding requires a helically wounded steel liner? And are you aware of the fact that this liner isn’t appropriate when you’ve to weld aluminum? If so, then you may be thinking about which liner you should use for that purpose. It is good to use Nylon or Teflon liners as pro welders prefer these liners to eliminate friction and aluminum scraping.

Wire Guides

You have to replace the wire guides you are using for welding steel because you can’t weld aluminum the way you typically weld steel. For welding aluminum using a spool, we suggest you get Nylon or Teflon wire guides because they are meant for this purpose. Moreover, if you want to reduce the resistance and shaving of aluminum during welding, follow this advice.

Contact Tips

Like other essential components of a welder, you also have to replace standard contact tips with a special one intended only for welding aluminum. As we know, the melting point of aluminum is much more than steel; that’s why the expansion of aluminum is also significant. So, we recommend you get the contact tip with a large hole nozzle.

Brake Tension

The column strength of steel is greater than aluminum. That’s why the welder sets its brake tension at a higher level which you can’t do when you’ve to weld aluminum. It is necessary to set brake tension at a lower level for aluminum in this way; you’ll need minimum force to drag the aluminum wire from the spool.

How to MIG weld aluminum using a spool gun?

If you have got a spool gun for aluminum welding with a MIG welder, then first, you must put the aluminum wire in this gun. To do that, you have to disclose the contact tip and detach the canister cover of the spool gun.

After that, take 8″ aluminum wire and cut it. Once you do that, connect the cable to the spool gun. Now put the aluminum spool into the spool gun’s canister and close it. Moreover, there is a tension arm on the side of the spool gun. Don’t avoid closing it.

Select the right contact tips according to the aluminum wire’s diameter. Once you get the appropriate contact tip, fix it in a spool gun and after that, install the nozzle. Now, your spool gun is ready for action.

It’s time to rectify the wire tension to ensure a suitable and steady aluminum wire feed. However, if the wire’s tension is loose, then the aluminum wire feed will be inconsistent. Before you start welding, it is a must to clean the aluminum surface to avoid oxides.

You can clean it by using a cleanser to remove oxides or other dust. Besides welding flux, the welding brush is excellent for scratching oxides over the aluminum surface. Always weld aluminum at an angle of 1 to 15 percent to get excellent results.

It is also advised to make sure that during the process of welding, the nozzle of the gun will not come in contact with the base metal. If it happens then, you will end up burning it. Further, use argon as a shielding gas to protect the weld from environmental contamination.

How to choose the right spool gun for your project?

If you are confused about which spool gun to buy, then, first of all, you should comprehend what spool guns are compatible with the welder you have or are going to purchase. Generally, the spool guns are evaluated to correspond to the performance of the welders they’re connected with.

If you go to the market and find various compatible spool guns for your welder, then we suggest you get the one that has a better duty cycle and rating. But as a rule of thumb, the more the duty cycle of a spool gun is, it’ll be intended for heavy and industrial applications, and hence it’ll be expensive.

Spool Guns
Diameter of Aluminum Wire
Duty Cycle
Compatible Welders
Spoolmatic 15A or 30A
0.030, 0.035, 0.047, or 0.062 inches
200A @ 100 percent
Millermatic 252 & Millermatic 212 auto-set
Spoolmate 200
0.030 or 0.035 inches
160A @ 60 percent
Millermatic 252 & Millermatic 212 auto-set
Spoolmate 100
0.030 or 0.035 inches
135A @ 30 percent
Millermatic 211 & Millermatic 141

What are the benefits of using a spool gun to weld aluminum?

If you are having trouble maintaining a stable arc while welding aluminum with a MIG welder, it is good to use a spool gun for this job as it provides a stable arc. Moreover, the stability of the arc from the spool gun enables you to create a weld paddle from a short distance which boosts your productivity.

Are you experienced in steel welding? If yes, then you have experienced bird nesting when switching from steel welding to aluminum welding. Also, you’ll see a significant reduction in bird nesting by utilizing a spool gun for aluminum welding. So it can save you valuable time, and you will carry out your task quickly.

Overlapped and twisted aluminum wires are the things you want to see in the end while welding. With the spool gun aluminum welding, you will see a spike in the welding quality, and the results you get are more delicate than they were. The reason is the chances of mistakes while aluminum welding with a spool gun is minimal and has better feed ability.

Further, the spool gun welding gives accurate welds on high heat-sensitive aluminum alloys that are usually tough to handle. If you don’t want to fail m in your aluminum welding endeavor, then you should use a spool gun.