Already found the stainless steel welding wire you want to use?
or already know who to weld stainless steel?
If your answer to both those questions is no, let me see how I can help.
In the hunt for stainless steel MIG wire, I look to give you a head start on the best stainless welding wire. And 10 tips for choosing your wire and for MIG welding stainless steel.
Stainless Steel MIG Wire Top Pick
The US Forge 308L is the top pick because it is the only one of the bunch where you can weld using C25 shielding gas as well as Tri Mix.
Using C25 is a real boon when you need to weld stainless steel at home and unable to go to the expense of buying Tri Mix to weld with.
This stainless steel solid MIG wire is a low carbon welding wire which encourages a smoother arc formation.
The US Forge 308L comes in 0.023" diameter, 0.030" and 0.035" in a 2lb. spool and 10 lb. spools.
The wire is used for welding type 302, 304, 308 and 347 stainless steels.
The US Forge ER308L wire is an all positions wire, meaning you can weld flat, horizontal, vertical and overhead.
Recommended shielding gas: 75% Argon, 25% CO2 also known as C25 gas. It is readily available, smaller tanks can be rented or bought and the gas is cheaper than Tri Mix to buy.
With this wire you may find the Hobart nozzle gel useful to buy to protect your nozzle from spatter particularly if you plan to use a C25 gas mix.
It is a low carbon wire with silicon content hence LSI as part of its name.
This wire is available in 0.023" on a 2lb spool. It is also available in 0.030 and 0.035 diameter sizes on 10lb spools.
The high silicon content is designed to help your welder produce a better arc as it welds. The Blue Demon 308LSI stainless welding wire should be used with types 304 and type 308, 321, 347 grades of stainless steel.
And it is an all position welding wire.
Recommended shielding gas: 98% Argon and 2% Oxygen for spray transfer with 0.030 diameter size wire.
For short circuit transfer welding Tri Mix (90% Helium, 7.5% Argon, 2.5% Carbon Dioxide) using 0.035" diameter wire.
Being able to weld with a 98% Argon, 2% Oxygen gas mix is useful as this gas mix is cheaper than buying Tri Mix. Though not as cheap as C25.
Is an extra low carbon stainless steel MIG welding wire.
This wire is available in 0.030" diameter size on a 2lb spool. The Hobart ER308L is also available in a 0.035" diameter size.
It is used for welding type 201, 304, 321 and type 347 stainless steels. And can also be used when joining different 300 series type stainless steels.
The Hobart ER308L stainless steel wire is suitable for welding single pass and multi-pass should you need to. It is suitable for flat and horizontal welding.
Recommended shielding gas: Tri Mix (90% Helium, 7.5% Argon, 2.5% Carbon Dioxide) is the shielding gas recommended by Hobart to weld with.
Although a shielding gas mix of 98% Argon and 2% Oxygen can also be used.
The Harris 308L stainless steel wire is another low carbon stainless welding wire.
It comes in 0.030" diameter on a 2 lb. spool and is available in wire diameter sizes of 0.023" and 0.035".
It is used for welding 304, 321 and 347 type stainless steel.
Is a wire recommended for flat and horizontal position welding.
Recommended shielding gas: Harris advises Tri Mix for short circuit method welding, because this gas preserves the corrosive benefits of the stainless steel and for minimum distortion.
Spray transfer 99% Argon and 1% Oxygen for Arc stability and a better weld puddle. They suggest 98% Argon and 2% Oxygen for thinner stainless steel gauges.
The Harris 309L comes in a wire diameter of 0.035" in a 2lb spool or a 10lb spool. Other diameter sizes that are available are 0.030, and 0.045 sized wires.
Harris recommends Tri Mix for short circuit method welding. because it preserves the corrosive benefits of stainless steel and the minimum distortion of the welded metal. Can be used to weld 18-08 base metals when they are corroded. And can weld dissimilar 300 series stainless steels.
It is a flat and horizontal position wire.
Recommended shielding gas: Spray transfer 99% Argon and 1% Oxygen for Arc stability and a better weld puddle. 98% Argon and 1% Oxygen when welding thinner stainless steel gauges.
What the Rest of This Article is All About
Just so you're happy you are in the right place.
What I am going on to cover is the best 10 tips for welding solid MIG stainless steel welding wire.
The wire used in a MIG Welder. The term MIG means Metal Inert Gas and it is an arc welding process. This process is also known as GMAW - Gas Metal Arc Welding.
This method of welding uses the electricity in a semi automatic arc welding machine - a MIG welder. A machine that continuously feeds welding wire from a spool inside the welder. The machine is connected to and feeds gas to the weld point from a cylinder of gas. This gas is referred to as shielding gas and protects the weld.
This is a short description of the MIG welding process. If you're not sure what MIG welding is, I have an article here on the site that goes into more detail. Go over and have a look.
Welding with stainless steel MIG wire needs a MIG welder of sufficient power set up for solid wire and connected to shielding gas, as stainless steel MIG wire needs to be gas shielded.
Also available is flux core stainless welding wire. There are actually two types of stainless steel flux core welding wire. One form needs no shielding gas, The other is gas shielded stainless steel MIG wire. And if you want to know more do click on the links.
10 Welding Tips for Choosing Stainless Steel Welding Wire
When you are looking to weld stainless steel there are some useful things to understand before you choose your stainless steel MIG welding wire.
1. The Type Of Stainless Steel You Plan to Weld
Stainless steels come in different types. These types reflect the different proportions of other metals, such as Chromium, Nickel and Molybdenum, that are added to the steel. The addition of the other metals affect the properties of the steel and its corrosion resistance.
Really? I hear you say.
Yes, and to have a successful MIG weld you should match the filler metal you plan to use to be compatible with the steel you plan on welding.
The types of stainless steels are typically used for different purposes and this may well give you a clue as to the kind of stainless steel you have if you are not sure.
The 300 series is the more common type of stainless steel.
For example, series 304 is used in cooking and for cooking pots for example, as well as for making cutlery and other kitchen equipment. 304 series stainless steels are not hardened by heat and are non magnetic. So if you take a magnet to a type 304 stainless steel it won't stick. It's a way of telling the type of steel you have.
You may have also seen the term 18-8 to describe stainless steels. The number 18-8 signifies the amount of Chromium (18%) and Nickel (8%) in the stainless steel and is a term commonly used in the food preparation industry. 18-8 is another way of referring to type 304 stainless steel.
304 grade stainless steel is also low carbon and contains no more than 0.8% of carbon.
316 type stainless steel is the next common type, and are mainly used in the food and beverages industry. This type of stainless steel is used because these steels are easy to sterilize clean. They do not affect the food they come into to contact with and give it that tell tail taste.
Yes, other steels and stainless steel may leave a tainted taste on the food or drink.
409 series steel are magnetic and are often used for the shiny stainless steel exhausts of vehicles.
430 is most often used for the shiny interiors of washing machines, dishwashers etc.
Netting this out. Look for compatible spools of filler metal to the stainless steel you're welding.
2. What Makes Stainless Steel Stainless
Stainless steel is composed of Iron, and other metals such as Chromium and Nickel added to give it its gleam and special properties. This type of steel is used in applications where other steels would quickly rust and mark. Hence the name stainless.
Some stainless steels types have Molybdenum added to enhance their corrosion resistance properties further.
It's not that stainless steel won't rust or indeed stain but it is designed and manufactured to be a lot more resistant to rusting than normal steel.
And that resistance makes it ideal for applications where the shine is desirable, low maintenance is needed and resistance to certain acids is wanted. For example the acids found in food and drink.
And so stainless steel is used a lot in the food industry. It is also found in the chemical, automotive and building industries - anywhere acids or water can corrode.
And resistance to rusting in contact with water is needed; hence its wide ranges of uses from washing machines to car exhausts.
3. Matching Your MIG Welding Wire to Your Steel
The reason you match your welding wire to your steel and go to the expense of purchasing stainless welding wire when MIG welding is to preserve the stainless, corrosion resistant properties of the stainless steel.
Point 1 covered the various types of commonly found stainless steels, Now let us take a look at the stainless steel MIG welding wires you should look for to match the steel you plan to weld.
ER308L MIG welding wire is typically used to weld 302, 304, 321, and of course 308 type stainless steels.
ER309L MIG welding wire is typically used to weld 304 type stainless steels and dissimilar stainless steels. This wire is particularly useful if you are not sure what type of steel you are dealing with. Also used for joining mild steel to stainless steel.
ER316L MIG welding wire is used to weld type 316 stainless steels. Take care though ... these steels are high end, and corrosion resistant steels with Molybdenum in them.
These types of stainless steels are used commonly where the steels hygiene and cleanliness status needs to be maintained at a high level.
Experts in the field usually do this type of welding. Because corrosion or germs within any minute gaps in the weld would cause hygiene and food safety issues.
Whichever steel you're planning welding, clean the surface first by removing any oil and grease. Then grind away any dirt or contamination will pay dividends. Just use the right kind of disc on your grinder.
4. Matching the Stainless Steel MIG Wire to your MIG Welder
The typical MIG welder used in the home workshop or garage is an up to 120 volt type welder.
A short circuit welding process is used by those welders utilizing a Tri Mix shielding gas. Spray transfer happens when the welding shielding gas has greater than 90% Argon mix. Size 0.023 or 0.030 diameter stainless steel MIG wire is ideally suited to the power produced by these MIG welders and works well.
Pick a 2lb spool of stainless steel welding wire if you're welding a small part or several small pieces.
Sure choose a 10 lb. spool of wire as the cost per pound will be cost effective.
But bear in mind that your MIG welder needs to be able to hold a 10 lb. (8 inch) spool and any wire you don't use needs to be stored well so that it is ready for you to use the next time you want to weld.
Should you have a more powerful welder running on 240 volts then your options open up to weld greater than 1/4 inch stainless steel using 0.035" diameter wire and above.
Check the welding parameters recommended by your MIG welder's manufacturer to weld stainless steel. Then compare to the welding parameters of the wire you have chosen. A combination of the two will enable you to find your starting MIG weld settings.
5. Look for the L or LSI when choosing your Stainless Steel Filler Wire
Stainless welding wires come in type names such as 308, 309 and 316 to match the stainless steel your welding. An L after the three numbers means that the carbon levels in the MIG welding wires are low, below 0.03%. Which will help prevent weld decay.
SI means the solid MIG wire has a higher silicon content. This is useful when you're welding as it helps to make the weld puddle more fluid. Because the stainless steel weld puddle can look notoriously sluggish and difficult to get that wet look.
Yet, you don't want to overheat the stainless steel and cause weld decay.
6. Joining Mild Steel to Stainless Steel
When you need to MIG weld mild steel to stainless steel what do you use?
Look for and buy 309L stainless steel MIG wire.
Type 309L stainless steel welding wire is the MIG wire to use as one of its useful properties is in joining mild steel to stainless steel.
The weld and the mild steel may well need protection from the elements so consider using galvanizing products.
7. Shield Gases for Solid Stainless Steel Wire
The shielding gas Tri Mix is the gas to use on stainless steel as recommended by the AWS (American Welding Society. Called Tri Mix as it is a mix of three different gasses. It contains 90% Helium, 7.5% Argon and 2.5% Carbon Dioxide.
The downside of Tri Mix is that it is a much more expensive gas to source and buy. Particularly if you only want to do the occasional bit of stainless steel welding. And You may not be able to find it in small tank sizes, those sizes most useful for the occasional weld in the home shop.
Alternatives are to use a shielding gas mix of 98% Argon and 2% Oxygen as a lower cost gas option.
Or a shielding gas mix with 1% Oxygen.
Be guided by the welding parameter chart given by the manufacturer of your stainless steel MIG wire as it will detail the shielding gas mix they have designed their stainless steel wire for.
Some wires are designed to be used with C25 gas (75% Argon and 25% Carbon Dioxide). It is the ideal wire to pick for the home welder as it is commonly the shielding gas you already have for MIG welding, keeping your costs to the minimum.
Either take a look at my linked article above to learn all about it or for an overview see the next point.
8. Beware Intergranular Corrosion
Intergranular Corrosion also known as weld decay is a thing.
Corrosion resistant alloys, such as stainless steel have Chromium added to give it its properties. In weld decay, the Chromium moves within the steel causing areas of the steel to become deficient in Chromium and so they rust over time.
It can happen when the stainless steel is heated at too high a temperature and for too long and that is easy to do when you're welding.
Intergranular corrosion is the last thing you want to happen to your welded stainless steel joint because, after all you want it to stay shiny, strong and unmarked.
What guards against it, is using filler metal that is low in carbon, as all the stainless welding wires detailed above are. And watching the voltage used when you weld.
You want it hot enough clearly, but not so hot as to distort and cause the chemical composition at the weld to change - leading to corrosion.
Using the correct shielding gas is another preventative.
For example, a blend of shielding gas with no more than 3% of Carbon Dioxide (one reason why Tri Mix works well). A gas blend with more than this percentage of Carbon Dioxide will see the excess Oxygen in the Carbon Dioxide reacting with the stainless steel in the heat of the arc resulting in problems with the weld.
However for stainless steel the Oxygen is a necessary element of the shielding gas reaction in the arc to protect your weld.
Argon blends with less than 5% of Oxygen, for example 98% Argon and 2% Oxygen work for MIG welding stainless steel.
This necessity for Oxygen in the stainless steel MIG welding process is why 100% Argon or even 100% Helium does not work.
9. YouTube Video Showing a Weld of Stainless Steel with Tri Mix
Bob Mofffat, welding instructor of Cowley College, Kansas compares welding stainless steel with C25 gas versus tri mix. This video concentrates on his experience with Tri Mix.
It's worth a watch because you'll hear in the video the different sound that welding with Tri Mix produces. It is different to the crackle sound you expect to hear when welding mild steel with C25.
Welding with Tri Mix gas produces less spatter, the bead profile is better, good weld penetration and you'll be reducing the risk of intergranular corrosion.
MIG Welding Stainless Steel with Tri Mix Gas
Video Credit: Weld.com
10. Do I need to use a Spool Gun to Weld Stainless Steel?
Nope, no spool gun is needed to feed stainless welding wire. Stainless steel MIG welding wire unlike Aluminum MIG wire is more robust and feeds well from the spool in the MIG welder up the hose to the MIG gun.
I hope you enjoyed my article "Stainless Steel MIG wire, 5 Best and 10 Welding Tips" and found the wires and tips I've given you useful. If after reading this article you decide that welding flux core is more what you are looking for then do take a look at my document on the subject "Stainless Steel Welding Wire Flux Core With a Home Welder".
I wish you all success with your welding projects.
Stainless Steel MIG Wire Welding Parameter Sheets
You will need to scroll down on the US Forge site to the stainless steel MIG wires to see the welding parameters.
To down load a copy of the welding parameters chart on the Harris site you'll have to select the resources tab and choose the welding parameters sheet from there.
To down load a copy of the welding parameters chart on the Harris site you'll have to select the resources tab and choose the welding parameters sheet from there.