TIG welding aluminum is one of the most popular processes among the professional welders for the professional racing teams. Hobbyists and auto enthusiasts also don’t leave behind. Most of the hobbyists and beginners welders have the question “can you TIG weld aluminum?”
Well, the straightforward answer is “yes”. You can.
But aluminum welding is one of the most challenging jobs to do.
Aluminum is considered to be the most unique metal. It is a great heat conductor, therefore; you will require a large input of heat to begin the weld as most of the heat will be dissipated through the surrounding base metal.
Controlling the heat input is really important to prevent the burn-through. And it is considered very challenging for beginners.
Melting temperature of aluminum
The melting point of pure aluminum is around 1200 degree F and doesn’t indicate any color changes before melting’ therefore; it will be quite tough to realize when it is going to be melted.
On the other hand, the oxide forming on the surface of the metal has a melting point of about 3200 degree F; while the boiling point of aluminum is 2880 degree F.
What’s more, the oxide is heavier than aluminum and you can’t ignore the trapping tendency of the oxide in the molten aluminum.
So, removing the oxide with a dedicated stainless steel wire brush is one of the most important steps to TIG weld aluminum.
But, the problem is the oxide layer reforms immediately and makes it difficult to view the weld puddle. To overcome this problem, using the alternating current (AC) with TIG process can take a crucial part as it will provide a cleaning action to remove the oxide layer on aluminum.
So, AC polarity is recommended while using the GTAW process to weld aluminum because of its ability to change the direction of current flow continuously.
Set the AC Output Frequency
“ how many times per second the power source switches polarity is referred to The output frequency”.
Most of the modern welding machine is preset to 120-hz output frequency while the older machines are preset to 60 hz. Higher AC frequency provides a more stable arc.
Setting up the output frequency in between 150 to 250 hz will prevent the burn-through and heating up the large area on thin aluminum.
related topic: how to mig weld aluminum in 2020
can you TIG weld aluminum without high frequency?
A low AC frequency from 80 to 90 hz is suited for ⅜ inch thick metals or even higher because it provides a wider weld bead profile.
Now, you may have a question “can you TIG weld aluminum with DC current”?
Again, the straightforward answer is “Yes“, you can.
When TIG welding thick aluminum (¼ inch), DC polarity is recommended as it provides deep penetration and strong weld with a single pass.
AC polarity is not recommended while TIG welding thick aluminum plates as it won’t provide you a deep penetration and strong weld with a single pass. You will have to make three or four passes to complete the joint which is really time consuming yet providing a weak joint.
According to the “rule of thumb” for TIG welding aluminum upto ¼ inch use 1 amp for every thousands of the metal thickness. For example, to weld 1/8 inch (0.125 inch) thick aluminum use 125 amps power source.
But remember this rule doesn’t not conform when the metal thickness is more than ¼ inch.
For example, welding a ⅜ inch (0.375 inch) metal will require 280 amp power source.
Another thing to consider while setting up the amperage for TIG welding aluminum is the joint geometry. While creating a T joint the heat will flow in three directions but in the case of butt joint the heat will flow in two directions only.
So, T joint will require more heat than butt joint, therefore; the amperage should be higher to weld a T joint.
Tips for a successful TIG welding aluminum
- Identify the base type of the aluminum before starting your welding project because few aluminum can’t be welded by the TIG process.
- Before starting your main project keep practicing basic hand placement and control to master positioning the torch and hand.
- Keep the torch flat against the table by bracing it with your hand base (from your forearm to the tip of your pinky finger). Keep it in a steady forward position with a slight tilt to the torch (5- to 15-degree).
- Maintain a close distance ( typically equal to the tungsten diameter up to ¼ inch) from the tungsten to the workpiece to prevent the arc from spreading too far which will overheat the piece and may cause burn-through.
- Keep practicing to work on the flow of your hand and torch movement with gloves, without striking an arc.
- Make sure your pressure on the hand is light and the grip on the welding torch is firm to slide your hand across the welding table in an even, steady motion.
- Never drag the torch, always push it ahead and maintain roughly a 90 degree angle with the torch and filler metal.
- Keep the hand with the torch smooth and steady as it slides while the other hand smear the filler metal.
Keep practicing these steps to get control over hand and torch placements and movements. Most of the beginners face trouble because of moving both hands altogether; resulting in touching the filler metal with the tungsten and becoming contaminated.
Filler metal for TIG welding aluminum
Chart of Recommended filler metal for different types of aluminum alloys is given below.
|Recommended Filler Metal(1)|
|Base Metal||For Maximum As-Welded Strength||For Maximum Elongation|
5183, 4043, 5356
5183, 4043, 5356
|5183, 5356, 5654|
(1) Recommendations are for plate of “0” temper.
(2) Ductility of weldments of these base metals is not appreciably affected by filler metal. Elongation of these base metals is generally lower than that of other alloys listed.
(3) For welded joints in 6061 and 6063 requiring maximum electrical conductivity use 4043 filler metal. However, if both strength and conductivity are required, use 5356 filler metal and increase the weld reinforcement to compensate for the lower conductivity of 5356.
However, many people ask “can you tig weld aluminum without filler metal”?
Again the answer is yes, cleaning of the material is the key point of TIG welding aluminum without filler metal. Removing the oxide layer from the base metal with a stainless steel wire brush and acetone is the most crucial step to tig weld aluminum.
What’s more, this process suits well when the material is thicker than ⅛ inch and joints with no gap.
Now the most important part;
Which welder is best suited for TIG welding aluminum?
Although there are varieties of TIG welder available in the market, all of them are not suited for aluminum welding. Only a few of them are well suited for aluminum welding projects. Among them AHP alpha TIG & Lotos TIG200 ACDC are considered to be the most versatile TIG welder than most other welders for aluminum welding.
Ahp alpha TIG 200x
AHP alpha TIG is a dual voltage (110/220v) AC DC welder having IGBT technology to ensure less power consumption.
This versatile welder allows you to weld a variety of metals including aluminum, stainless steel or steel with different thickness ( ¼ inch aluminum and ⅜ inch mild steel also the thinner gauge materials).
The HF start and the included foot pedal provides you the easiest way to control and operate your machine.
Thanks to its switching option between TIG and stick allowing you to operate both TIG and stick according to your requirements.
With these amazing features, this welder also provides a 3 year warranty along with a really affordable price which is under 1000$.
Being easy to operate it is also considered to be the best welder for beginners and hobbyists.
Similar tig welding machine Primeweld tig225x
Lotos TIG200 ACDC
If you are in a tight budget and willing to get a versatile welder, “Lotos TIG200 ACDC” would be the best choice for you.
It is also a dual voltage (110/220v) unit along with dual frequency (50/60 hz).
Dedicated square-inverter technology is provided for precise fine aluminum welding.
It allows you to weld thinner gauge aluminum along with thick aluminum upto ⅜ inch.
So, finally we can say that although TIG welding aluminum may be tough, you can do it with proper techniques and with a suitable welder.
One thing you have to keep in mind that nothing is more important but practice. Without practice you won’t be able to make good looking weld beads on aluminum.