Millermatic 140 MIG Welder Review

As an Amazon Associate we earn from qualifying purchases. ToolPickr is reader-supported. When you buy through links on our site, we may earn an affiliate commission.Learn more

In Brief: Millermatic 140 Review

Created by the Miller company, the Millermatic 140 welder offers an Auto-Set feature and several wire settings for home hobbyists. This product comes packed with enough power to handle mild steel and can be operated with an aluminum spool as well. It combines portability with ease of use and Miller’s commitment to high-quality products.

The Miller Company continually supplies welding customers with high-quality products that last.

This company cares about its customers as well as its employees and provides welding supplies and equipment that set many industry standards.

The Millermatic 140 includes all the quality and customer satisfaction of the Miller product line. This portable welder makes it easy for beginners and experienced users alike to enjoy every welding project.

Key Specifications of Millermatic 140


The Millermatic 140 provides the power needed to use steel from 24 gauge to 3/16 inch mild steel.

With an input of 115 V and the option to change the diameter of the wire for each project, this welder packs many specifications into one convenient product.

Take a look at the Millermatic 140 in action –

Check out the long list of specs for the Millermatic 140:

Input Voltage
115 VAC
Rated Welding Output
90 A @ 18 Volts DC
20% Duty Cycle
Amperage Range
30-140 A
Maximum Open-Circuit Voltage DC
28 V
Weight with Gun
60 lbs.
Measurements10-5/8 in. w x 17-1/2 in. l x 15-3/4 in. h
Wire Feed Speed Range
No Load
35-420 IPM
Wire Feed Speed Range
Feeding Wire
15-390 IPM
Solid Wire Diameter0.6-0.8mm
Stainless Wire Diameter0.6-0.8mm
Flux Cored Wire Diameter0.8-0.9mm
WarrantyCheck Manual
Manual Mode
Thermal Overload Protection
Tip-Saver Protection
Accessories6 ft. power cord
10 ft. M-100 gun and cable
10 ft. work cable
Extra contact tips for 0.6mm and 0.8mm wire

Unique Features

The Millermatic 140 welder offers several features to benefit its users. The Auto-Set feature tops the list as the most important and surprising quality of this convenient little welder.


Plugging in the right information about the wire and metal used in your project causes the welder to activate the Auto-Set feature. It automatically detects the correct parameters and sets up the system for your project on its own.

Included Gun

The Millermatic 140 includes a welding gun attachment, allowing you to begin working with it right out of the box. The gun attachment installs easily in just a few minutes.


Thanks to its Smooth-Start function, this welder runs without splattering or popping on startup. This, in turn, makes it safer for you to operate.

Tip Saver

When the contact tip touches the workpiece, the output shuts off and remains off until the whole unit is reset. This safety feature protects you as well as the internal parts of the gun.

Versatile Wire Options

Both aluminum and mild steel work with this welder. Aluminum should measure between 18 gauge and 14 gauge, while steel should measure between 0.8mm and 4.8mm.

10-Foot Work Cable

An extra-long work cable provides easy access for beginners who need extra space to tackle projects. Even experienced welders enjoy the length of this easy-to-use cable.


Performance & Ease of Transportation

Boasting a surprisingly high performance output and a light, portable weight, the Millermatic 140 delights home welders of all skills.


The Millermatic 140 performs beautifully when used with thin metal. Its ability to run with different types and thicknesses of wire allows it to complete a variety of projects with results that regularly please customers.

The features and settings of this simple but functional welder make it easy for beginners to learn how to weld. It holds up well for years of frequent use and manages tasks of many sizes.

More experienced users who operate the welder without the Auto-Set function enjoy an even more precise weld along with longer periods of use.

Ease of Transportation

This welder comes in at the ideal weight for many customers. It’s heavy enough to stay firmly in place while you use it but light enough to bring it along to other locations as needed.

Even with the included gun attachment, the Millermatic 140 remains lightweight and easy to move around. This lighter design allows even more control over your projects, both big and small.

Its portable dimensions ensure that this welder travels well and sets up quickly, too.


Weld Quality and Available Options

The Millermatic 140 welder offers high-quality welding for almost any skill level. This long-lasting and sturdy welder offers several settings and precise welding options to cover many types of materials.

Some customers alter the adjustments on their own to create the weld quality they prefer. Others rely on the Auto-Set feature to accomplish this.

The right choice for you largely depends on the project and your own welding experience.

The Millermatic 140 features three available VAC (voltage in alternating current) options:

  • 115 VAC Model: This model offers the lowest voltage and the fewest settings. Intermediate welders enjoy using this version.
  • 115 VAC Model with Auto-Set: This model includes the Auto-Set function, unlike the other two choices. Beginners prefer this version.
  • 230 VAC Model: This model provides the highest voltage and most power of the Millermatic 140 line. More experienced welders stick to this version.

Ease of Maintenance, Repairs & Warranty

Miller offers many replacement parts for purchase through the company web site. The site sorts accessories and parts by individual product numbers, so locating the right parts remains easy for all customers.

All versions of the Millermatic 140 make regular maintenance and upkeep simple. The instruction manual provides a basic checklist of three-month and six-month routine maintenance to keep in mind.

Every three months, change torn or damaged labels, clean the terminals, and check and replace cables as needed. Clean inside the unit every six months.

The product includes a limited warranty, which states Miller will provide replacements or repairs for damages or failures caused by faulty workmanship. The warranty excludes other sources of damage.

The Miller warranty covers 5 years for parts and 3 years of labor for the main power rectifiers.

It covers 3 years of parts and labor for the wire feeders, power sources, and coolant systems, and 1-year of parts and labor for most of the rest of the product.

Some parts of the welder fall within warranties provided by their specific manufacturers, such as the engine.

Customers can call 1-800-4-A-MILLER to request warranty information.


How do you weld aluminum with the Millermatic 140?

Preheat the metal before welding. Use the spool designed specifically for aluminum, and avoid the Auto-Set feature if possible when welding aluminum.

Can the Millermatic 140 handle TIG welding?

No; TIG (tungsten inert gas) welding requires a different kind of welder.

Can you make adjustments to the Auto-Set specifications?

Yes. After you choose the Auto-Set function, you can easily turn it off and make more precise calculations on your own. More experienced welders often use this product in this way.

Can you use flux core wire with the Millermatic 140?

Yes, but not with the Auto-Set feature. You must set the specifications yourself when using flux core wire.

Price of Millermatic 140

This welder comes in at a reasonable and comparable price to other models and brands that offer the same kinds of features.

As a portable welder, however, its price remains higher than other brand names.

Miller offers this welder on the lower end of their price range, making it an affordable and beginner-friendly way to start welding.


Who Should Buy Millermatic 140?

Beginning welders and those who want to expand their welding skills frequently purchase and enjoy working with the Miller 140.

Thanks to its portable and lightweight design as well as its lower price point, this welder makes an ideal solution for anyone who needs to travel with a welding machine.

The Millermatic 140 works beautifully for customers who primarily focus on mild steel or aluminum.

It cannot handle the wide variety of metals available from other welders but can cover a range of thicknesses.

It provides quality welding for residential customers, hobbyists, and individuals who want to incorporate welding into other hobbies they enjoy, too.

Our Recommendation

The Millermatic 140 performs exceptionally well, even though it doesn’t offer as much power as some others on the market.

Although its smaller size prevents it from working with many types of metal, it can still handle aluminum and mild steel with stunning results.

Despite its few limitations, we recommend the Millermatic 140 for any hobbyist interested in exploring an interest in welding.

We also recommend this welder for anyone in need of a portable machine and a user-friendly experience.


Last update on 2024-05-30 / Affiliate links / Images from Amazon Product Advertising API

About Karen Taylor

Karen is an expert woodworker. He has been working as a professional in the domain for more than 12 years now. She has experience of working on a variety of power and other tools while working on her projects.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.