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How To Set Up A Mig Welder With Gas!

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Hub on the left. Drive rolls on the right.

Hub on the left. Drive rolls on the right.

Getting Set To MIG Weld!

So you bought a used MIG welder and you want to know how to set it up with gas for welding mild steel or aluminum?

Well you've come to the right place. But I must give you a little warning first. You should not used this as your only source for getting your welder set up. Your welder should have an owners manual and maybe even a service manual. That would be a good source of information for you. But I do know from experience that those manuals are not set up for easy reading. However, you should be able to find the owners manual on the manufacturers website unless you have a really cheap Chinese made welder, where getting information out of them is like looking for a needle in a rice Pattie.

Removing retaining ring so I can put the wire on the hub.

Removing retaining ring so I can put the wire on the hub.

Installing Wire!

The first step to getting your MIG welder ready to weld is to install the wire. So what you need to do is take off the retaining ring and spring, and then put the wire spool on.

Be certain you have aligned the hole on the spool with the little pin on the hub.

Also be sure the spool feeds the wire from the bottom.

Before you set up your gas you should set up your wire properly and make sure it's working properly.

So the first step is to open up your welder where the hub and drive rolls are.

MIG Welding Wire

Closed spring tension. I am tightening it, but just a little bit.

Closed spring tension. I am tightening it, but just a little bit.

Push The Wire Through The Guides!

After you attach the spool, take the wire from the spool and feed it through the first guide, across the drive roll, and through the liner guide. The second guide is the one that feeds through to the hose liner and welding gun.

Be sure that the wire is on the correct drive roll size. For example, the wire that I am using is .30, and the drive roll can take either .35 or .30.

The drive roll has a stamp on it that shows you what size it takes.

After you get the wire through the second guide it's time to close and tighten the spring tensioner for the drive rolls.

This is an important feature. You do not want to tighten it too much and you don't want it too loose either. The key is to push the wire through after tightening it so that you can feel how well it is going to feed. If it's too stiff it will jam up. If it's too loose it jam up as well.


Take The Nozzle and Contact Tip Off!

Be sure the machine is unplugged.

OK, now you want to take the nozzle and contact tip off of your gun. The reason you want to do this is because if your contact tip is attached when you run the wire through the hose it can easily get caught on the tip because the opening is so small, so you want an open space there.

After you take the nozzle and contact tip off, straighten out the hose as much as possible. The reason for this is because you don't want the wire trying to navigate through your hose as you feed it through because it can get jammed up that way.

MIG Contact Tip

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Feeding The Wire Through!

After you accomplish all of the above you should be ready to turn the machine on and get the wire feeding through to your gun.

But before you do that make sure your machine is set to continuous feed if you have spot welding and pulse welding capability.

So plug the machine in, turn it on, and the pull the trigger on the gun. The wire should feed nicely through until it sticks out of your gun (without the nozzle or contact tip). If it does not you need to fiddle with the hub, spool, or drive roll (with the machine unplugged).

Let the wire come out several inches and then reattach the nozzle and the contact tip.

Snip off excess wire so that there is about .25 inches of wire sticking out.

Congratulations you are almost ready for the gas.

A: Pressure gauge. B: Gas flow.

A: Pressure gauge. B: Gas flow.

Shielding Gas and The Flow Meter!

The first thing you want to do when it comes to your cylinder of shielding gas is make sure that it is secured well with a chain so that it cannot fall over.

Second, you want to have the safety cap on the cylinder at all times you are not using it.

You should have a flow gauge to attach to your bottle of gas. This gauge tells you how much pressure is inside the bottle (A), and then second gauge tells you how much is flowing (B).

This gauge should be installed on the cylinder in the vertical position. Tighten the nut on the stem securely.

Your machine must have an output fitting for connecting the gas. Attach the other end of your host to the flow meter.

You will open the cylinder by opening it slowly, and then I suggest you open it up all the way if it everything seems fine with flow meter connections. Stand away from the valve.

How much gas do you want to flow? The average is anywhere from 15-25 CFH. This stand for cubic feet per hour.

Too much gas makes the weld cool to fast, and too little will cause your weld to have pockets of gas, neither is good. So you want to find that sweet spot where you have just enough. Also, keep in mind that gas is not cheap so try to find where you can weld with the least amount of gas as possible.

For example, if it is a little bit breezy you may have to increase it. But if there is no wind you can turn it around.

MIG Welding Tutorial;

Spoolmatic 3 spool gun for my Millermatic 200.

Spoolmatic 3 spool gun for my Millermatic 200.

Setting Your MIG Welder Up For Welding Aluminum!

You'll get varying opinions on how to weld alminum with a MIG welder but bascially you have two options:

1. Use a short cable and use a regular welding gun.

2. Buy a spool gun that works on your machine.

The cheaper route is to use a short cable. But if you do you should get a teflon liner. The reason you want a short cable and teflon liner is because aluminum is softer and bunches up really easily (it's called bird nesting). So a short (and straight) cable and teflon liner helps this problem from happening. But it's not ideal.

The ideal solution is to buy a MIG spool gun because the wire feeds directly from a drive roll on your spool gun and makes the process very simple. However, most spool guns are costly, and often you need an adapter to attache it to your machine.

The shielding gas you will probably be using is 100% Argon. You can use Helium but research this mixture first.

If you mix C02 with your Argon you will ruin your weld because C02 creates oxide on your aluminum. I know it's tempting to try because you probably have a 75/25 mix of Argon and C02 but don't do it!

Also, you will most likely be using DC Reversed Polarity (DCEP) to weld aluminum.

Lastly, you will need to match your aluminum wire with the aluminum you are welding. That's the easy part. One of the most common wires is ER4043 which will weld 6061 and 6063 aluminum.

Make sure you check your owners manual or the manufacturers recommendations for welding aluminum with their machine before using any advice you get online, including here. You just want to be sure you are doing it all 'by the book'.

What Questions Do You Have About Setting Up Your MIG Welder?

Kathe from newyork on October 31, 2020:

Very Helpful

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