Learning to MIG weld aluminum with a spool gun may lead to some of your
longest days in the welding shop since there are so many different things that
can go wrong with your settings and technique. Everything is far more difficult
and sensitive with aluminum, and therefore you’ll need to spend a lot more time figuring out your wire speed, stick out, amperage, and plenty of other key
settings. Here are some tips for getting started with a spool gun on your MIG
Don’t Forget to Clean Your Metal
While you can sometimes get away with not cleaning your metal if it’s brand
new and doesn’t have any residues on it, the best bet for a high quality MIG
weld with aluminum is to start with clean metal that you either clean with a wire brush or an angle grinder for really tough oxidation or residues. Either way, a little prep work will go a long way to preventing weld contamination. Another tips would be to brush in the same direction rather than back and forth so you do not pull the contamination you are brushing back through the material.
It’s also common practice among most welders to use a little acetone to clean up a weld before getting to work on it. Or now they make wipes that are super easy and convenient.
MIG Gun Angle for Welding Aluminum
Usually a 10-15 degree angle gets the job done on aluminum welding, as is the case for most MIG welding projects. However, in the case of aluminum, getting this wrong could case more problems with your weld than you would experience when MIG welding steel. Attention to detail is critical when maintaining the proper angle.
We find that pushing aluminum is better than a pull. Pulling or drag angle can cause dirty welds.
Voltage and Wire Speed for MIG Welding Aluminum
The first place to start with your adjustments for MIG welding aluminum with
a spool gun will be your amperage and wire speed. Too much wire and too much heat will do a number on your weld and will leave you with a mess to clean up with your angle grinder. Use the chart on your welder to experiment with a few different voltage and wire speed settings before going to work.
Choose the Right Gas and Filler Metal
The best gas for MIG welding aluminum is 100% argon. The recommended flow rate is about 20 cubic feet per hour.
If your arc is jumping around or hissing too much, there’s a good chance that
you need to adjust your shielding gas flow. Too much shielding gas will cool off the weld puddle and make it incredibly difficult to keep a steady, tight arc.
When it comes to filler metal the most popular is ER4043 or ER5356 aluminum MIG wire. We stock a few good economical options such as Blue Demon, Crown Alloys or Hobart. Also be sure you select the right size wire and that you have tips to match for your Spoolgun.
Having some bird nesting (wire piling up) you are not alone! Check the tension on the wire and make sure you have the right drive rolls in your machine.
Temperature of Metal for MIG Welding Aluminum
Preheating aluminum will give you a much cleaner and neater weld that will
also be easier to make. If you’re working in a cold climate, consider preheating
your metal a bit before striking your arc.
Keep Testing Your Settings for MIG Welding Aluminum
Even the pros have to run a few test passes to dial in their settings just
right for welding aluminum. You don’t want to cover your work piece with spatter or burn up your tip right at the start. It’s better to test your gas flow, wire speed, stick out length, and amperage first in order to work out the kinks with an erratic arc or too much oxidation in your puddle.
Wire Stick Out for MIG Welding Aluminum
A little extra wire on your tip will save you a lot of hassle and save you
from burning up your tips for your MIG gun. The ideal stick out will be around
3/4”, which is much longer than what you would use for MIG welding. On some projects you may even find that you need a longer stick out than that! However, too much stick out will dump too much metal into your puddle and you could loose control of the puddle and even leave a bunch of spatter on your aluminum work piece.
Invest in a Spool Gun for your MIG Welder
Aluminum wire for a MIG welder tends to easily jam if you feed it like regular MIG wire. No matter how economical you may try to be, you really don’t
want to spend your day feeding a jammed wire out of your MIG welder! You’ll save yourself a lot of headaches by purchasing the right spool gun that will make it much easier to feed wires with your MIG welder. If you need help figuring out what spoolgun is compatible with your machine let us know!
Choosing the Right Spoolgun
*Also option to use a push pull gun on the Miller 255 units!
Rebel 215 - Tweco 160 Spool gun
Rebel 205 -Tweco 160 or Tweco 200A
Baker's did a review video and demo on the Spoolmate 100 vs 150 watch below for more tips and info on set up!
Learn more about affordable and reliable Spool Guns at Baker’s Gas.