Millermatic 135 Review: What to Know Before Buying?

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Millermatic is a leading manufacturer of welders and welding equipment. Miller has been in the welding industry for over 50 years, so they know what it takes to make a good welder. The Millermatic 135 is one of their newest models that offer superior performance at an affordable price point.

The Millermatic 135 is Miller's most popular MIG welder. It can be used for both new and old school applications, providing the user with a versatile machine that will last for years to come.

If you're looking for a new welder or just want to learn more about Miller's latest product, then this article is perfect for you.

This review provides information on what you need to know before investing in one of Miller's Millermatic welders.

Keep reading to find out why Miller's Millermatic 135 is the best welder for you and your business.

Millermatic 135 Specifications

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Millermatic 135 Review (In-depth)

Millermatic 135 MIG welder

01. Duty Cycle Rating

One big disadvantage of MIG welders is that they heat up. They have to rest and cool down, or the machine will not work well. But, if you are welding for a short time and then resting for awhile, it can work well.

Duty Cycle Rating Millermatic 135

The Millermatic 135 has a duty cycle of 2 minutes of continuous welding with 8 minutes of rest at 100%. The duty cycle also changes based on the settings you use: for example when the setting is 47 amps, it goes back to be 50% duty cycle and will do 1 minute of continuous welding followed by 9 minutes off; but if you set the setting at 125 amps then it only does 12 seconds of continuous welding followed by 9 minutes 48 second off.

It's important to remember that most of the time you won't be welding for more than a few minutes at a time. It's not advisable to weld continuously for long periods of time. You should tack your pieces first, and then do the welding if you are working on something bigger. The breaks between tacks will give enough opportunity for cooling down in-between work sessions which will help you get a better weld.

For the Millermatic 135, the duty cycle is pretty good and for all practical purposes it is more than.

Key Points: Duty Cycle Rating of Millermatic 135 welder; MIG Welder Heats Up Easily - Must Rest Regularly; The Machine Will Not Work Well if Used for More than a Few Minutes at a Time

02. Amperage and Voltage Specifications

There are two ways that you can use when using a MIG welder. You need to know your amperage and voltage. Amperage is how fast the welder will go, and voltage is how hot it will be. The Millermatic 135 has a voltage of 115 volts and amperage of 135 amps. That means it goes quick, but not too hot or deep into the metal.

The Millermatic 135 is good for beginners because they don't have to know all the other things about welding yet before they can use this one. It has simple dials that control voltage and amperage. It's not too hot to be dangerous for beginners, but it still does a good job on any weld you need to do in your home or garage.

03. Wire Feed Speed and Diameter

The wire feed speed on a MIG welder is the rate at which it uses wire and it determines how quickly you can weld. The Millermatic 135 can weld at speeds ranging from 20 inches per minute to 600 inches per minute depending on what setting you have it on. It can use both solid-metal MIG wire (0.06 mm or 0.08 mm) and flux-core MIG wire (0.08 mm or 0.09 mm).

04. Dimensions

The Millermatic 135 is a welder that is small enough to be portable. It's 17 ½ inches long, 10 5/8 inches wide and 15 ¾ inches tall. It weighs 60 pounds including the welding torch, so it's light enough to carry around. If you need to put it in your car, you'll have trouble because it won't fit in most cars! You should consider this welder if you need a good one for home use.

05. Millermatic 135 Circuit Board

The Millermatic 135 is a heavy duty MIG welder. It has the newest microprocessor technology that is designed for industrial applications and welding thick metals. Moreover, the Millermatic 135 is an excellent MIG welder for the auto industry, fabrication shops and other industrial settings.

Besides this, the Millermatic 135 has a patented wire feed speed control system that allows welders to make full use of current technology without overloading the operator with too many options. It also features functions such as gas flow rate adjustment, power output adjustment and wire feed speed adjustment.

The circuit board diagram for this welder is shown below.

Millermatic 135 circuit board

06. Millermatic 135 drive motor (Drive Motor Protection)

The Millermatic 135 Drive Motor is special because it has a protection circuit. That means that if something happens to your machine, it will stop and fix itself. The Millermatic 135 has its own protection circuit that protects it from overload and inoperable conditions, therefore preventing any further damage or injury due to faulty equipment. If you notice malfunctions with power source on this welder, simply release the gun trigger until it resets itself and feed wire again for uninterrupted welding experience.

07. Tip Saver/Short Circuit Protection

The Tip Saver is an important safety feature in the Welding Gun. It will turn off electricity to prevent damage if a short circuited occurs, and also when you release your trigger during welder use for some extra protection against accidents. You need to monitor it carefully so that any problems can be dealt with promptly before they get worse or cause injury!

08. Process/Polarity of Millermatic 135

The Millermatic 135 welder is one of the most versatile welders in its class. It can use either GMAW (Solid wire with shielding gas) or FCAW (Self-shielding wire − no shielding gas). For GMAW, Polarity is DCEP − Reverse polarity, that means you should connect Cable To Gun with positive (+) output terminal and Cable To Work Connect to negative (−) output terminal. On the other hand, when you use FCAW (self-shielding wire), Polarity is DCEN straight polarity, that means you should connect Cable to Gun with negative (−) output terminal and Cable To Work Connect to positive (+) output terminal.

09. Welding capacity of Millermatic 135 Welder

The machine has different capabilities depending on what type of metal you are welding. You can weld mild steel to stainless steel, with a flux core wire as thin as 16 gauge.

You can weld metal. It has different capabilities depending on what type of metal you are welding, for example:

  • Mild steel (1/8th to 24 gauge)
  • Stainless steel (1/8th inch to 24 gauge)
  • Flux Core (3/16th inch to 16 gauge).

Make sure that the material you are using matches the material of your machine.

Compatible with all types of metal, but once again make sure to match the type of wire you are using and the type of material you will be welding.

Schedule Maintenance of Millermatic 135

We know that this tool is going to be used for a variety of different tasks. It's the optimal welding machine that anyone can have in their garage, and with frequent use, it needs to be taken care of. The regular maintenance schedule is going to ensure that all the parts function properly at all times.

The following information is more than enough for you to understand what goes on in this machine:

Schedule maintenance after 3 months:

  • Replace unreadable labels that are difficult to read.
  • Repair or replace cracked weld cable.
  • Clean and tighten weld terminals.

Schedule maintenance after 6 months:

  • Blow out or vacuum inside.
  • During heavy service, clean monthly.

What is the Best Gas to Use with Your Millermatic 135?

If you are just starting to weld with the Millermatic 135, it is best for you to go through this section because these tips and tricks will help get better results from your new welder.

If not, let us skip ahead straight into evaluating how good a job the Millermatic does by someone who has used welding before (a "newbie").

There are 3 gases that can be used when welding:

  • C25 is 25% CO2 and 75% argon added to it. This is helpful so you don't have to change out tanks as often.
  • 100% CO2 - this gas is only used for cutting steel and not recommended if you are just starting off welding with your Millermatic 135. You'll have to change tanks a lot.
  • Tri-Mix3 : 90% HE + 7-1/2% AR + 2-1/2% CO - this gas can be used for both cutting and welding steel.

The argon is the most common gas used because it offers a few benefits that CO2 doesn't.

For instance, argon welds are smoother and easier to control than those done in CO2.

( REMARK: If your Millermatic 135 becomes "less than perfect" and leaking after a while, fix it properly by having CO2 and Argon tanks replaced or just contact the store where you bought it from. )

A few pointers as a beginner that will help you make better welds are: Do not try welding thick metal less than 1/8 inch thick consisting of multiple metals like cast iron, stainless steel, 2 different types of steel.

For thinner metals up to 36 SWG [0.093"] there is no problem using one set but if dealing with heavier metal over 3/16"-1/4" then different settings are necessary for the different layers of metal to weld properly and avoid a mess.

Millermatic 135 wire feed problems & Solutions

The Millermatic 135 wire feed is a great machine for welding, but it can be frustrating to use.

It's easy to get frustrated with the Millermatic 135 wire feed when you're trying to weld and it keeps shutting off or not feeding properly. You may have even tried everything from changing the settings on your machine to adjusting how you hold the gun, but nothing seems to work.

We've got some tips that might help! we have accumulated some common problem areas and how to fix them.

Let's get started!

01. No weld output; wire does not feed; fan does not run.

  • Ensure the power cord plug-in receptacle is secure.
  • If the power is out or you suspect a break in the circuit breaker, replace fuses and reset to get the flow of electricity.
  • Power the system up by switching on the power.
  • The circuit breaker for the power supply to your welding machine should be reset if open.

02. No weld output; wire does not feed; fan motor continues to run.

  • If the thermostat is overheating, turn off the gun trigger switch and allow the fan to run until the unit has cooled. The thermostat closes when it cools.
  • Make sure that the gun trigger leads are always secure.

03. No weld output; wire feeds. 

  • Get the metals touching by tightening down the work clamp.
  • Miller recommends changing the contact tip before you start welding to ensure proper spatter clearance.
  • Check the polarity of your welding machine.
  • Check to see if the thumbscrew for securing the gun end is tightened to keep it from bouncing while welding.

04. Low weld output. 

  • Check the input voltage for compatibility.
  • Turn the voltage switch to the desired position.

05. Electrode wire feeding stops during welding.

  • Replace the damaged parts of a gun cable, which may include straightening it out.
  • The drive roll pressure will also need to be adjusted.
  • Replace drive roller groove.
  • Adjust hub tension.
  • If the contact tip is clogged or blocked, replace it with a new one. The too big-sized tip may be required for some wires.
  • Clean or replace the wire inlet guide if it’s dirty or clogged.

06. "Hey my welder keeps shutting off every few seconds" 

If your wire feeder keeps shutting off after a few arc seconds this is usually because the machine misreads the amount of welding cable being fed through it. The machine thinks it's feeding too much wire (when in reality it's actually not feeding any). To fix this problem, you need to adjust your sensitivity settings.

07. "My Tungsten Keeps Falling Out of my Project"

If your tungsten keeps falling out, it's probably because you haven't tightened the collet enough yet. It's very important that you do this to keep the sharp tip from becoming damaged or worse – emitted into outer space (I've heard of this happening before). I recommend only tightening them until they are snug and leave no gap in between the inner peace and your tungsten wire. If you have a high-end Millermatic welder they come with a special tool to measure when it's tight enough.

08. "The Welds on My MIG Welder Look Ugly"

If you're noticing that your welds aren't looking so pretty, this is probably because you haven't cleaned the wire feeder out. Over time with normal use, melted metal will build up in your wire feeding mechanism and because all sorts of friction resulting in intermittent signals to your power supply which can make it read as if there's too much welding cable being fed at once. This causes inconsistency and usually leads to ugly-looking welds. To fix this problem, try taking out the wiring on the back of the machine then spraying some compressed air where parts touch or check Online for tutorials. If these don't work for you, feel free to visit a certified technician who can take care of things for a small fee!

09. "My MIG Welder is making a Grinding Noise" 

If your welder is making a grinding noise, try to disconnect the gas hose then re-connect it. This should clear most of the debris in the regulator from clogging it up. If this doesn't solve your problem, you could always do some more advanced troubleshooting.

10. "My welds are coming out with porosity and slag" 

Millermatic 135 users commonly have issues with porosity being left behind in their finished welds due to poor technique. So be sure not to overheat your metal otherwise you might end up burning away more of that protective flux and exposing yourself to more porosity.

Can you weld aluminum with a millermatic 135?

It is possible to weld aluminum with a millermatic 135, but it's not easy.

To be able to do this, you need the right equipment and materials. You have to heat up your aluminum first because welding cold metal doesn't work well. It needs to be heated up until it reaches 400 degrees Fahrenheit for example. When the metal is at the right temperature, you can start welding and create a bead on each side of the joint that you want to fix together before heating them again for another round of welding if needed.


The Millermatic 135 is a top-of-the line MIG welder that will provide you with years of quality service. If the machine isn’t performing optimally, it may be time for routine maintenance to get your wire feed back up and running like new. Be sure to consult our guide on how best gas to use with your millermatic 135 before starting any project or if anything goes wrong. Remember that aluminum can only be welded using an electrode specifically designed for this purpose; do not attempt welding in other metals!


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