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Choosing The Right Filler Metal To Get The Job Done

MIG TIG Stick Oxy Symbols

When it comes to being successful in welding, not only do you need to know how to produce a quality weld, but you need to know how to correctly choose your filler metal(s). 

Selecting the correct filler metal will create the needed strength, longevity and integrity of the weld. Knowing how to choose the correct filler metal for your welding application can be very difficult depending on your knowledge of the trade. An experienced welder, technician or welding engineer will understand the AWS classifications of filler metal(s) [(AWS) American Welding Society]. This technical data sheet will help entry level hobbyists determine how to choose the correct product to complete the job.

Here are a few important questions to ask yourself before you get started.

Filler Metal Isle at Forney Industries


First, start off by identifying your base metal material (aluminum, stainless steel, mild steel, cast material, etc-). Your filler metal must be compatible with your base material as closely as possible, as this is the most important part of the selection process.  Each base metal has its own unique properties, meaning dissimilar compositions are not going to bond well, or at all.

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Material ProcessSteel Stainless SteelNickle AlloysAluminum Cast IronCopper BrassTitanium Magnesium AlloysSkill Level
Stick (SMAW) X X X XModerate
Flux Core (FCAW)XXLow


When it comes to the quality of your base metal, it should be clean. Grind or wire brush your material to remove surface contamination. For steel, if you are unable to clean your material and you are trying to weld through light to medium corrosion, grease, rust or light paint, you will need a filler metal with a higher arc force and good cleaning action. Those characteristics can be found in a filler metal that includes a deoxidizer which helps bring contaminates to the surface of the weld. If the contamination gets trapped in the weld puddle it will enhance brittleness as well as reduce the strength of the weld.

Best Filler For Contaminated Steel
Stick Electrodes (SMAW) E6010, 6011


Tensile strength and elongation ratings are two other very important factors to selecting the right filler metal. Ultimate tensile strength is the amount of stress a material can withstand before breaking or failing under tension. Elongation (or plastic strain) is the degree to which the specific material deforms under mechanical loading, usually expressed as a percentage. Elongation occurs when the material is stressed between the yield strength and the ultimate tensile strength before rupture or final failure of the component. Ask your metal distribution expert for the correct ratings of the material you are purchasing. When welding steel, you must pick a filler metal with a minimum strength equal to or higher than the tensile strength of your base metal(overmatch). Overmatching is most suitable when working with steel. If you use a filler with a tensile strength weaker than the base material, the weld will not be as strong as the base material and may be less secure. In other situations when you are welding materials other than steel, overmatching is not recommended. If you overmatch, the weld can become brittle and crack or tear when tested.

Tensile Stress-Strain Diagram


Flat position welding is the most ideal for any project, but unfortunately, that may not always be possible. When welding out of position (any position other than flat), make sure you select the right filler metal for the job. Some filler metals can only be used in certain positions. When the filler metals are formulated to run out of position, they are less prone to have porosity and inclusions in the weld bead, which can weaken the weld and cause it to fail.  (AWS coding; 1=Flat, Horizontal, Vertical, Overhead, 2=Flat, Horizontal, 3=Flat only, 4=Overhead, Horizontal, Vertical down, Flat)

Plate Position


The next step, is figuring out what diameter of filler metal to use and determining the right amperage for the thickness of metal you have. If your machine is lower amperage (90-100A), you will need a smaller diameter filler metal, this will still work but may slow down production. Bigger diameter filler metals will work if you properly prep your material and take proper steps to select the right filler metal. With these steps, you can create a good, structurally sound weld. 

120V ~MIG Wire= .024 – .030” Stick Electrode= 5/64 or 3/32”

230V ~ MIG Wire= Up to .035” Stick Electrode= Up to 5/32

Electrode DCEN DCEP AC Position Penetration Usage5/64″ 3/32″1/8″5/32″3/16″
E6010 X AllDeepMinimal Preparation 40-7070-120110-170140-210
E6011 XXAllDeepRough, high spatter 40-7070-120110-170140-210
6013XXXAllLowGeneral35-60 40-80 70-120 100-150  
7014XXXAll MediumSmooth, easy, fast 70-110100-150150-210 
7018 XXAllLowLow hydrogen, strong 70-9080-150150-210 
308 XXAllLow Stainless Steel 40-7070-110110-150  
ElectrodeMaterial ThicknessElectrode Diameter InchesWelding Current AmpsArc Voltage DCEPWire Feed Speed IPMTravel Speed IPMShielding Gas Flow SCFH
24 ga.030″35-5015-1785-10012-2015-20
22 ga.030″40-5015-1790-13018-2215-20
20 ga.025″55-8515-1770-12035-4015-20
18 ga.035″70-10016-19100-16035-4015-20
Solid Wire1/8″.035″120-16019-22210-29020-2520-25


The environment you are working in will also be an important detail to be aware of when choosing the right filler metal, as well which welding process to use. Is your weldment (welding environment) easy to maneuver or is it stationary? If your weldment is stationary, you must use a filler metal that is formulated for out of position welding. Will you be welding indoors, or will you be outside? Will there be wind that could blow away shielding gas, or should you use a self-shielded filler metal? If you use a wire with an inert gas, you must make sure you are in the right environment or you will not be pleased with the outcome.

Outdoors & Portable Indoors & Less Portable
= Stick welding and Flux Core welding = Some stick welding, TIG welding and MIG welding
Skill Required ModerateLowLowHigh
Work MaterialMild Steel, Stainless Steel, Cast Iron, Nickle AlloysLow Carbon Steel, Low Alloy Steel, Stainless Steel, Aluminum, Brass, Copper, Nickle AlloysMild Steel(DC TIG): Low Carbon Steel, Low Alloy Steel, Stainless Steel
(AC TIG): Aluminum
Shielding GasNot Required, Electrode acts asInert Gas Required, Argon and CO2, BlendsNot RequiredArgon
Input Power50/60
Hz 1- Phase: 115V or 230V
Hz 1- Phase: 115V or 230V
Hz 1- Phase: 115V or 230V
Hz 1- Phase: 115V or 230V
Output PowerAC: 30-300 A
DC: 30-160A, 5-280A
1- Phase: 30-300A1- Phase: 30-300ADC: 5-150A, 1-200A, 3-350A, 5-700
AC/DC: 1-200A, 3-400A, 5-700A
Filler MaterialElectrodeElectrode/WireElectrode/WireWelds with or without
Slag & SpatterConsiderableLowConsiderableNone
Filler FeedManualContinuousContinuousManual
Burn ThroughSomeSomeSomeExcellent Control
Weld PositionsAllAllBetter FlatAll
Spot WeldingWith experienceGoodGoodOK
Weld QualityNot for showGoodNot for showExcellent
Environment Dirty & Rusty, windyCleanDirty & Rusty, WindyVery Clean
Process BenefitsCan weld at long distance from the machine
Inexpensive options for welding
Versatility, portability, and reliability
Out-of-position welding
High welding speeds
Same welding machine for MIG and Flux Core
Out of position welding
Deep penetration for thicker materials
Increased metal deposition rates
Same welding machine for MIG and Flux Core
Concentrated Arc
High quality clean welds
No smoke or slag
Thin materials
Common Applications Outdoor repairs
Rusty metal
Farm & Ranch
Maintenance & repair
Aluminum fabrication
Farm & Ranch
Garage/ auto body shops
Light industrial
Maintenance & Repair
Outdoor repairs
Remote areas
No shielding gas available
Farm & Ranch
Maintenance & Repair
Auto restoration, repair
Motor sports
Sport aviation
General repair & fabrication
Metal Artwork

Now that you have considered the questions above, you are ready to choose which filler metal is best for your welding application. But wait, you head to your local welding supply store and realize there are more selections than you’re prepared for! What does each filler metal do, and how do you know if what you’re choosing is right for your application? Let’s discuss electrode coating and ensure you are choosing the correct one.



MIG welding wire ranges from .024” to .045”. When using a 120V machine, you will be using  .024” or .030” diameter wire for the best results. Using .030” wire vs. .035” has very slight differences in weld bead appearance. An .030” wire gives you a wider sweet spot range and avoids blowing breakers. It also has the advantage of requiring less amperage and puts less strain on your machine. Once you get into 230V machines, you may use up to a .035” wire diameter.


Base MetalType of MIG Wire AWSCommon Inert Shielding Gases
Carbon/Mild Steel: (GMAW)ER70S-675% Argon/ 25% Co2, or 90% Argon/ 10% Co2, or 100% Co2
Carbon/ Mild Steel: (FCAW) E71T-GSN/A
Stainless Steel: (GMAW) 20% Chromium & 10% NickelER308100% Argon or 90% Argon 10% Co2 or Tri-Max
Aluminum: (GMAW) 5% Magnesium contentER5356100% Argon
Aluminum: 5% Silicon most commonly usedER4043100% Argon

When it comes to TIG welding, there are many different diameter filler rods you can choose from. Most of the time the size of your rod is based upon the thickness of your material. More times than not, you don’t want your filler metal to be much bigger than the thickness of your material. If you try using a larger diameter filler rod when adding it into your puddle, it will chill the puddle too quickly and cause an inconsistent bead. If you’re ever in a pinch, you can even use some of your MIG wire as a filler.


Base MetalType of TIG Filter AWSCommon Inert Shielding Gas
Mild SteelER70S-6100% Argon
StainlessER309L100% Argon
Aluminum ER4043100% Argon 


Unalloyed Electrodes
ER- Electrode/Rod MIG or TIG
AWS A5.187- (X x 10 = 70KSI x 1000) = Min tensile strength per inch= 70,000 PSI
S- Solid Wire
6- Amount of deoxidizing agent and cleansing agent. (Copper coating of this wire)
Unalloyed Electrodes
E- Electrode
AWS A5.207-(X x 10 = 70KSI x 1000) = Tensile Strength = 70,000 PSI
1- Welding Positions (1 = All Positions)
T- Tubular electrode (Flux core)
GS- Usability & performance (Self shielded, or gas shielded)

ER70S-6 (DCEP)~ Hard wire is a general purpose welding wire for fabrication of mild steel. The wire contains deoxidizers that help provide better wetting, giving a flatter bead shape and the capability of faster travel speeds. It is usually used with 75/25 shielding gas (75% argon/25% CO2) or with higher contents of argon, such as 90/10. It may also be used with 100% Co2.

E71T-GS (DCEN)~ Flux core wire is for welding mild steel. It is a self-shielding wire due to the tubular design that contains a granular flux within the wire. The granular flux is formulated to remove the impurities of a weld and bring them to the surface rather than using a gas. This wire is ideal for windy, outdoor welding and is a low-cost welding solution.

ER308 (DCEP)~ This stainless-steel wire consists of 20% chromium and 10% nickel. Some applications that use stainless steel wire are the food and beverage industry, maintenance and repair of parts you do not want a high level of corrosion on. Welds type 301, 304,308,321 and 347 stainless steels.

ER5356 (DCEP)~ E5356 aluminum wire features 5% magnesium content and a bright finish. It flows freely at 1,180°F (637.8°c) and provides less “bird nesting” on push-type MIG welders. Applications include diesel engine bases, truck frames, cargo tanks and gun mount bases.

ER4043 (DCEP)~ E4043 aluminum wire contains 5% silicon and features a bright finish. It flows freely at 1,155°F (624°C) and works well with spool guns. Some applications include truck bodies, pressure vessels and structural components.


Base MetalType of Electrode AWSPurpose
Carbon/ Mild SteelE6010, E6011, E6013, E7014, E7018, E7018ACGeneral and/or high strength 
Stainless SteelE312-16 Austenitic- ferritic steel 
AluminumE40436xxx, 3xxx,or 2xxx series aluminum 
Cast SteelNomacastNon-machinable
Cast Steel/IronNI-CAST 99%, NI-CAST 55% Machinable 
High Alloyed Electrodes
E- Welding consumable (electrode)
AWS A5.4312- Chemical composition
X- (Some time a “L” is represented) L= Low Carbon
-16- Usability -16 or -17 has stabilizing elements (AC possible) -15 = DCEO only. Also represent tensile strength- 116,000 PSI

E6010 (DCEP)~ Mild steel, all purpose, all position “pipe rod”. Deep penetrating, with excellent arc stability and wet in. This rod is ideal for welding in all positions and produces a quality weld with x-ray inspection requirement characteristics. With light slag that’s easy to remove. Applications include construction, shipbuilding, general purpose fabrication, maintenance welding, and pipe welding. Elongation=28%

E6011 “SUPERSIXTY” (DCEP, DCEN, AC) ~ Mild steel cellulosic electrode for high penetration welding of carbon steels in all positions. This electrode displays a stable arc with rapid puddle solidification, which facilitates operation in the overhead and upward vertical positions.  Light slag calls for easy clean up. Can run at relatively low amperage. Excellent for rusty steel due to high arc force. Useful for galvanized tanks, steel casting and pressure pipe. Elongation=22%

E6013 “GENERAL PURPOSE” (DCEP, DCEN, AC) ~ Mild steel all position, general purpose rod with medium to shallow penetration. Medium to heavy slag for easy clean up. Excellent for poorly fitted joints. Smaller diameter rods are well suited for low amperage on thin sheet. Can be used on all types of mild steel where ease of operation and good appearance is required. This rod has excellent arc ignition, soft and stable arc with low spatter. Ideal for light gauge metal, duct work, etc. Elongation= 17%

E7014 “SUPER CONTACT” (DCEP, DCEN, AC) ~ This electrode is an excellent beginner rod. This is a high deposition mild steel, iron powder coating electrode with medium to shallow penetration. It is known for smooth arc characteristics, good arc stability, and easy slag removal. Excellent for sheet metal and ornamental work. Elongation=17%

E7018 (DCEP, DCEN) ~ Mild steel, low hydrogen, all position rod. Suitable for hardened steels where no preheat is used. The low hydrogen content reduces cracking and peeling of the weld material. Recommended for applications involving structural steel, construction, pressure vessels, boilers, pipes, bridges, power plants, naval, and other high-strength steels where hydrogen control is imperative. This electrode displays a stable arc, smooth and finely rippled bead pattern with easy slag removal. Elongation = 22%

E7018AC (DCEP, DCEN, AC) ~ Same welding characteristics as normal 7018 electrodes but can run on AC machines easily. Suitable for welding frames, hitches and chassis.

E312-16 (DCEP, DCEN, AC) ~ This stainless-steel rod is an austenitic-ferritic electrode primarily used for repair and maintenance of austenitic and ferritic steels, high magnesium steels with alloy and non-alloy steels, and other materials that are not easily weldable.  This electrode offers a stable arc, minimal spatter, easy slag removal, and a smooth bead profile. Its high tensile strength and crack resistance makes it ideal for welding crack sensitive steel or dissimilar metals. Elongation= 22%

NOMACAST (DCEP, DCEN, AC) ~ “Nomacast” is non-machinable cast iron specialty welding electrode that feature a non-conductive coating that is specially developed for welding dirty, heat affected and oxidized cast iron. Ideally suited to cladding contaminated casting prior to joining with high nickel alloys. NON-MACHINABLE, though ok to grind on. Typical applications include machine bases, pedestals, frames, and housing where heat and machinability is not a crucial factor. Hardness= RC 39

SUPER NI-CAST 99% (DCEP, DCEN, AC) ~ Super Ni-cast 99% nickel electrode is used for maintenance and repair of all commercial types of cast iron, as well as for fusing iron to cast steel. This electrode produces spatter free welds in all positions using minimal amperage. The weld deposits are fully machinable. Typical applications include automotive engine blocks, transmission and pump housing.

SUPER NI-CAST 55% (DCEP, DCEN, AC) ~ Super Ni-Cast 55% Nickel electrode is intended for repair and maintenance welding of cast iron, cast steel, and for joining these base metals to steel, copper, and copper alloys. This electrode produces spatter-free welds in all positions using minimal amperage. The welds deposited are fully machinable. 

ElectrodeMaterial ThicknessElectrode Diameter InchesWelding Current AmpsArc Voltage DCEPWire Feed Speed IPMTravel Speed IPMShielding Gas Flow SCFH
24 ga.030″35-5015-1785-10012-2015-20
22 ga.030″40-5015-1790-13018-2215-20
20 ga.025″55-8515-1770-12035-4015-20
18 ga.035″70-10016-19100-16035-4015-20
ER70S-6 Solid Wire5/64″.035″100-13018-20160-22025-3020-25


Brazing is another application in bonding metals. It joins materials that may be more difficult to bond with other application. In some cases, when using a brazing rod, the braze can become stronger than the base material itself. Also, this application is appropriate when you are trying to bond dissimilar materials to get the greatest strength of both materials. When brazing, you are using a gas torch with a filler material. The melting point of the brazing rod (840°F, 450°C) is lower than the base material to ensure the base material is not melting with the filler. They must also be protected from contamination, so use of an added flux for bare brazing rod or use a brazing rod that is flux coated.

Some advantages of brazing are: great for complex assemblies, minimal issues with joining large joint areas, great heat and stress distribution, preserve coating and cladding, excellent for dissimilar materials, joining nonmetals to metals, bond vastly different thicknesses of materials to each other, and little to no fishing work to be done. 

Brazing AlloyBase MaterialTensile StrengthMelting Point
Easy-Flo AluminumAluminum70,000 PSI 723°F (389°C)
4043 Bare Aluminum Aluminum Sheet, Aluminum
Intrusion, Aluminum Cast 
27,000 PSI 1,155°F (624°C)
Super Sil- Flo Copper base metals, some bronze base metals 40,000 PSI 1,200°F (649°C)
 Oxy- Acetylene Mild SteelLow Carbon steel45,000 PSI 2,700°F (1,482°C) 
 Bare BassBrass, Steel, Cast Iron63,000 PSI 1,620°F (882°C)
 Bronze Brazing Flux CoatedBrass, Steel, Cast Iron65,000 PSI  1,598°F (870°C) 

EASY-FLO ALUMINUM BRAZING ~ This rod makes it easy to braze aluminum and zinc-based metals with an oxy acetylene or propane torch set up. Great for repairs on irrigation pipes, carburetor bowls, aluminum boats, lawn mower housing and castings. No flux is required.

4043 BARE ALUMINUM ~ Matches most types of sheet and cast aluminum. Designed for use with torch flame or inert gas welding process. When welding with torch flame, it is recommended to use with ALUM-A-FLUX.

SUPER SIL-FLO BRAZING ~ Ideal for large and small copper tubing installations. Self-fluxing on copper. Sil-Flo is not recommended for ferrous metals such as iron or steel. It is also an effective, economical alternative to copper-silver alloy rods.

OXY-ACETYLENE MILD STEEL WELDING ROD ~ High quality mild steel welding rod for repair of low carbon steels. Copper coated rod has .06% max carbon and .17% max manganese. Great rod for projects around the house or commercial use.

BARE BRASS BRAZING ROD ~ Balanced zinc and copper alloy. Features excellent ductility and is smooth flowing with low fuming. Excellent for brazing sheet metal pipes, fenders, water tanks and many cast iron applications. Requires flux.

BRONZE BRAZING ROD, FLUX COATED ~ High quality low fuming bronze brazing rod with flux. Formulated for high tensile strength and ductility. Smooth flowing. Excellent for most brazing uses. Flux coated for best cleaning action.

The focus of this technical data sheet has been to help you determine what filler metals to use with the associated processes and material you’re working with. As you can see, there’s a large variety of filler metals depending on the specific process and developing a firm grasp of this information will require extensive practice and experimentation. This guide is to serve as a reference and road map to begin developing a better understanding of which filler metals correspond to specific applications. It is highly encouraged that as a welder you never stop experimenting with different applications and pushing the limits of your welding abilities. Don’t be afraid to try new materials that are outside of your comfort zone. Find what works best for you and always strive to become a better, more well-rounded welder than you were yesterday.

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