Aerospace Welding and Brazing

Aerospace Welding and Brazing

Weld repairs to aircraft and component parts use such equipment as gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), plasma arc welding, and oxyacetylene gas welding. When repairs of any flight-critical parts are required, it is extremely important to make the weld repairs equal to the original weld. Identifying the kind of metal to be welded, identifying the kind of welding process used in building the part originally, and determining the best way to make welded repairs are of utmost importance. Aerospace welding certification for personnel in the UK is CAA BCAR A8-10.

After the weld is completed, the weld must be inspected for defects. All these things are necessary in order to make an airworthy weld repair.

Aircraft welding is one of the three commonly used methods of joining metals without the use of fasteners. Welding is done by melting the edges of two pieces of metal to be joined and allowing the molten material to flow together so the two pieces will become one.

Aerospace brazing

Aerospace Brazing is similar to welding in that heat is used to join the material; but rather than melting, the metal is heated only enough to melt a brazing rod having a much lower melting point. When this brazing rod melts, it wets the surfaces to be joined, and when it cools and solidifies, it bonds the pieces together.

Soldering is similar to brazing except that brazing materials normally melt at temperatures above 425 °C (800 °F), while solders melt at temperatures considerably lower.

Aircraft weld repairs

The next step in making aircraft weld repairs is to decide the best process to use, considering the available state-of-the-art welding equipment, and then deciding the correct weld-filler material to use. Before any weld repairs can be made, the metal parts to be welded must be cleaned properly, fitted and jigged properly, and all defective welds must be removed to prepare for an aircraft quality weld repair.

Most large business or agencies conduct their own certification tests, or they have an outside testing lab validate the certification tests.

Pitfalls are many, for example, when using GTAW equipment, a weld can be contaminated with tungsten if the proper size electrode is not used when welding with direct current reverse polarity. Another example, the depletion of the inert gas supply below the critical level causes a reduction in the gas flow and will increase the danger of atmospheric contamination.

Electric welding equipment versatility requires careful selection of the type current and polarity to be used. Since the composition and thickness of metals are deciding factors, the selection may vary with each specific application. Metals having refractory surface oxide films (i.e., magnesium alloys and aluminum and its alloys), are generally welded with alternating current (AC), while direct current (DC) is used for carbon, low alloy, non-corrodible, and heat-resisting steels.

Oxyacetylene gas equipment is suitable for welding most metals. It is not, however, the best method to use on such materials as stainless steel, magnesium, and aluminum alloys; because of base metal oxidization, distortion, and loss of ductility.

If oxyacetylene is used for welding stainless steel or aluminum, all flux must be removed, as it may cause corrosion.
Clean parts to be welded with a wire brush or other suitable method prior to welding. Do not use a brush of dissimilar metal, such as brass or bronze on steel. The small deposit left by a brass or bronze brush will materially weaken the weld, and may cause cracking or subsequent failure of the weld. If the members are metallized, the surface metal may be removed by careful sandblasting followed by a light buffing with emery cloth.

Visually inspect the completed weld for the following:

The weld has a smooth seam and uniform thickness. Visual inspection should be made of the completed weld, to check for undercut and/or smooth blending of the weld contour into the base metal.

The following steels are readily weldable; plain carbon (of the 1000 series), nickel steel (of the Society of Automotive Engineers (SAE) 2300 series), chrome-nickel alloys (of the SAE 3100 series), chromemolybdenum steels (of the SAE 4100 series), and low nickel-chrome-molybdenum steel (of the SAE 8600 series). [] is a great help to anyone operating within the industry. “Buying from” or “selling to” aerospace companies, you can put contact emails straight into your address book in Outlook Express, you can compile a list of addresses in a print basket, you can use hotlinks to bounce straight onto other aerospace company websites. Aerospace fabrications and welding [] is an article giving technical guidance and you can click on the logo top or bottom to return to the searchable database giving contact details of companies worldwide providing this service.

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Welding Certification Positions a Simplified Explanation

Welding Certification Positions a Simplified Explanation

If you talk to any welder and ask, “Are you certified?” you’re most likely to hear a big, happy “YES!” in reply. The real question should be, “What positions are you certified in?” There is never a simple answer to welding certifications, but the basics of welding positions are easy!

Welding certifications are broken down into two main categories and a couple more positions. The first category is structural welding, mostly used for welding square-shaped objects. Structural welding certifications are the most common and just about any student welders will pass them. The second type of welding certification is for welding pipe. Not many welders have this type of certification, as very few of them are able to pass the exam.

Welding positions are just that, positions! Structural welding is done in the flat, horizontal, vertical, and overhead positions. Square shapes give a straight line to weld, therefore – one angle, and one position at a time. Pipe welding, on the other hand, never allows the welder to use a single angle or position! When welding pipe, the angle and position of the weld are never the same, as both are consistently changing as you work through the entire weld.

Welding certification positions have a coding system that welders always refer to. Structural welding positions are coded one through four. One is for flat, two is for horizontal, three is for vertical, and four is for overhead welding. Most welding certifications are done in groove welds and what that means is the weld joint is beveled. The abbreviation that is used for groove welds is “G”. Putting together the coding system is simple. For practical reasons, most structural welders will take two welding certifications. The first is the 3G position which is a groove weld in the vertical position. The 3G position qualifies the welder to weld in the flat, horizontal, and vertical positions with a single test. The 4G position is a groove weld in the overhead position which qualifies a welder to weld in the flat, horizontal, and overhead positions with a single test. When combining the 3G and 4G welding certifications, the welder is qualified to do structural welding in all positions.

Pipe welding certifications use the same coding system but add a few more positions and combinations. For pipe welding, the numbering system goes from one through six. One is for a pipe that is rolled in the flat position, two is for a pipe that is running up and down along the surface of a wall, four is a pipe that is horizontal running along the floor, and six is a pipe standing on a 45 degree angle. The 1G pipe position covers flat welding, the 2G covers horizontal welding, the 5G position is a combination of overhead, vertical, and flat welding, and finally the 6G position covers the flat, horizontal, vertical, and overhead positions in a single weld joint. There is no such thing as a 3G or 4G Pipe Welding certification. For practical reasons most pipe welders are certified in the 6G position and that covers all of the structural and pipe welding positions in a single test. It’s the hardest welding position and the pay scale for a welder with a 6G welding certification can be more than double that of a structural welder’s salary.

My name is David Zielinski and I am a 6G Certified Welder. If you would like more information about welding certification positions then visit my website All if the information is free and it is full of accurate, hard to find, real life welding tutorials!

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Wire Feed Welding

Wire Feed Welding

Wire feed welding is just another name to for MIG welding. The basic idea behind wire feed welding is that you use a welding wire that continually feeds through a MIG welding gun when you squeeze the trigger.

This is a continuous welding process. As long as you keep your finger on the trigger and the welding wire touching the base metal you will be able to wire feed weld all day. There are many different types and brands of welding wire that you can use for many different welding applications.

The most commonly used welding wire is more than likely an AWS ER70S-6 classification wire. This particular class of wire is used in virtually all welding and fabrication shops for many different types of welds. I highly recommend to use a precision layer wound welding wire as opposed to a random wound wire.

A layer wound spool of wire will be evenly wound onto the spool from left to right with each layer of wire neatly sitting next to the other. This makes it a lot better for wire feedability as there will be no bends and small kinks in the wire.

Random wound wire will be just literally random wound onto the spool in any old-fashioned. Because of the way that the wire is wound on the spool in a random fashion, the wire will cross over itself a few times. And as the spool starts to fill up with the wire, every time there is a crossover of the wires it can make a small bend in the wire.

These small bends in the wire can affect your feedability which in turn will affect your overall weld quality.

When using a MIG machine or a wire feed welding machine you will also have welding consumables that need replacing on a regular basis. Every MIG welding gun will have a contact tip and a shroud or a nozzle. And then depending on which brand of welding torch you have there will also be a gas diffuser or some kind of insulator. Some brands of wire feed welding guns like the Bernard range will actually have the gas diffuser built in with the tip holder.

I guess that most DIY or home welders will use what is called a gasless welding wire. This is also known as a flux cored wire. Be careful though because there are two different types of flux cored welding wires. Well actually there are a lot more than two, but for general home welding make sure that you get a gasless MIG welding wire that is a E71T-GS.

Now if you do decide to use a gasless MIG welding wire you are going to have to change the wire feed rolls. The reason for this is because it is a flux cored wire the wire is not solid all way through. So because the flux is on the inside of the wire the wire is very soft.

If you use your standard feed rolls you will see that they are shaped with a vee groove in them which is what you want to use if you are using a solid wire. The problem is that if you use the same feed rollers on your softer flux cored wire you will find that the wire gets squashed and this can lead to all sorts of wire feedability issues so to solve this problem you need to use what is called a knurled feed roller. The knurled feed roller has, like, many small teeth in the grove of the feed rollers. These little teeth help to grab the softer wires and give it traction and push it through the whole length of the welding gun.

Finally you’re going to have to use a slightly larger contact tip for when you use a flux cored wire.

So if the wire diameter is for argument sake 0.9 mm you want to use a 1.0 mm contact tip. This will greatly help with the smooth feeding of the wire and allow better welding.

Check out my site for more detailed information on mig welding [] And also why not check out my page on gasless mig welding [] I go through with photos and a video showing more detail about using a gasless mig welder for MIG welding..

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What is Stud Welding? Details About the Stud Welding Process

What is Stud Welding? Details About the Stud Welding Process

What is Stud Welding?
Although many people believe that there is only one basic welding application, there are actually many different applications involved with welding. One of these areas is the stud welding process, where a bolt or formed nut is welded onto another metal piece. This process may include using stud welding equipment to automatically feed the bolts into the spot welder.

Stud welding, or arc stud welding, involves joining the stud to a flat plate by using the stud as an electrode. The polarity that is chosen for the particular stud welding application will depend on the type of metal that is used. For example, aluminum usually requires direct-current electrode positive, or DCEP; while steel demands direct-current electrode negative, or DCEN.

The weld nuts used in stud (or arc) welding usually have a flange with some type of small nubs that melt during the process in order to form the weld. The necked down, un-threaded part of the weld nuts also help to form the desired weld. Another aspect of this type of welding application is the use of a flux, called a ferrule. A ferrule is a ceramic ring that concentrates the generated heat, preventing oxidation and retaining the melted metal in the desired weld zone.

One particular type of stud welding process is called capacitor-discharge welding, which differs from traditional stud welding in that it does not require flux. The process uses a direct-current arc from the capacitor, and welding time is between a mere 1 and 6 milliseconds. Since welding time is shorter in capacitor-discharge welding, the welder can finish the bonding with little oxidation and no actual need for heat concentration.

What are Weld Studs?
Stud welding systems use weld studs as a part of this efficient application. These studs are between 14 gauge to 3/8″ diameter, can range from 1/4″ to 5″ or more in length, and are discharged from capacitors. The tips on the weld end of the stud have two purposes:

oTiming. The tips act as a timing device that keeps the studs off of the base material that is being welded.

oDisintegration. Weld end tips disintegrate once the trigger is pulled on the welding gun, melting and solidifying the weld onto the base material.

What are Arc Studs?
Arc studs are usually loaded with an aluminum flux ball on the weld end, which helps to promote the welding process. These unique studs are an integral part of stud welding equipment, and they can range from a #8 up to a 1 1/4″ diameter stud.

Sunbelt Stud welding is a stud welding company that offers an array of stud welding products for different industries.

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Advantages of Laser Welding Over Traditional Welding Methods

Advantages of Laser Welding Over Traditional Welding Methods

Since the introduction of the first laser in the early decade of the 1960, this unique technology has experienced a fast-paced evolution. In modern times, light amplification technology has been utilized throughout a variety of applications, from manufacturing to military armaments. However, thanks to the persistent progression and comprehensible research of laser technology, they are more efficient, powerful, smaller and economic than in previous generations.

One industry that has benefited greatly from the introduction of laser technology is metal welding. During the operational process known as laser welding, a light beam is amplified providing a focused and strong origin of heat that is used to connect multiple pieces of metal. The high energy density of the laser allows the surface of the material to briefly turn into a liquid state allowing for the pieces to be bonded. This innovative welding process allows for a much more rapid fabrication time and output when paralleled to alternative welding methods. Because of the high welding rates, it works particularly well for large volume applications.

When compared to traditional welding techniques such as arc welding, laser welding has some similarities however it also has its own unique characteristics. The most prominent dissimilarity between two welding processes is the manner in which the energy is reallocated. Like gas metal arc welding, laser welding is process based on fusion performed under inert cover gas. However it provides a much faster welding rate by a substantial margin in addition to generating very little, if any, distortion to the metal piece. Furthermore laser welding does not require the work piece to make a full electrical circuit, unlike gas metal arc welding or electron beam welding. This style of welding not only provides a technical improvement and gain, it also cost-effective benefit over similar techniques. For example, due to the vacuum chamber requirement of electron beam welding, equipment and operation costs can generally be higher compared to laser welding.

Several more advantages include on-line processing, sorter cycles and higher uptimes, and the fact that this type of welding can be used to weld magnetic materials. Because this welding procedure can be transmitted in pulses, meaning that the minimal amount of heat is added is another benefit. The continuous pulsing of the beam allows the metal to cool between each pulse of heat. As a result, there is a very small heat affected zone. This makes laser welding an ideal technique for thin metals or when welding is required near electronics. The small contribution of the energy in conjunction with the visual procedure results in more possibilities when it comes to tooling and materials.

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Welding Jobs: Got Gas? (As Long As It Is Natural You Can Get Rich Making The Most of It)

Welding Jobs: Got Gas? (As Long As It Is Natural You Can Get Rich Making The Most of It)

Most people don’t think of welding and natural gas at the same time they think of wealth building.

These two elements (welding and natural gas) will soon converge into an economic power house for any entrepreneur with vision. Find out why.

Why Welding? The metal shop in high school closed long ago – along with auto shop and wood shop. For decades, most welders started out in high school metal shop – and now for two decades metal shop has been considered, “mental slop” by the elites who only see “intelligent pursuits” as those involving computers and other tech.

Sadly, this has caused a huge and growing shortage of welders and other trades.

Just as the powers that caused “computer class” to replace “metal shop” – the powers that rule the welding industry don’t understand their own industry well enough to update the focus of welding. This is because the welding game has changed.

“Tradition” can be a train wreck – and that is the case with welding education.

Welding education today is like a re-run of the movie, “Back To The Future.” It is 1950 all over again when you step into a junior college welding class. Hours and days are spent on book learning. Hours and days are spent on learning techniques and processes the average welder will never use.

Yes, one or two things taught in structural welding classes are applicable in the job market – enough to get the average welder coming out of a year of more of education a job welding for $10 to $15. Last time I checked you can make that much cleaning windows…

Where is the Entrepreneurial Opportunity in welding?

Pipe welding covers a lot of ground – there is carbon steel pipe, aluminum pipe and stainless pipe. Each category has a variety of types, sizes and applications. Welding any and all of them produces excellent incomes. Individuals can make $75,000 to $150,000 a year without a welding truck (called a rig).

Welders with their own rig are making up to $300,000 a year.

Welders who own 3 rigs and weld themselves while managing other welders can and do top $500,000 with a relatively small business organization.

Where does natural gas come into this?

The United States has $178 Trillion in natural gas and oil on U.S. Federal Lands alone! We are not tapping that gas now – the vast majority of the wells which have recently caused the USA to become the largest producer of oil and gas on the globe are located on private lands. The reserves of oil and gas on private lands is beyond belief – and no longer disputed. We will be swimming in oil and gas for generations to come.

Did you think solar and wind would win the day?

Much like propaganda in any country at any time in history, wind and solar is NOT what most people think. The power production is minuscule. When your neighbor gets solar on their house – you paid for a large portion of that system because of large federal and state subsidies. Solar and wind (after all the noise about them) still make up less than 5% of all power production – and a very high price has been paid by all us for it.

On the contrary, oil gas operate in a pure, true market environment.

The oil and gas industry will not be shut down because the government “pulls the plug” on subsidies. AND natural gas is a very low emission, low polluting energy source!

My brother held 11 patents for co-generation technology in the 1980s. He built a large business because the market was subsidized. When the subsidies were stopped, the business stopped. The same thing will soon happen for solar and wind.

Oil and gas produce huge amounts of energy and won’t be replaced for 100 years.

Natural gas usage will increase dramatically in the coming years. We will soon see over the road diesel trucks repowered with natural gas (for example). Honda has made a natural gas Civic for many years. Police cars, taxis and city buses are powered by natural gas right now.

Where will people fill up?

There is a small but growing number of natural gas stations across America. And many homes in America run on natural gas. Filling stations which can be installed at residential locations are on the market now. Would you like to fill up your car at home for $3? You can! The Russians are working on airplanes powered by natural gas. The possibilities are endless – and many will be reality sooner than you think. And yes, you could build a business just installing natural gas filling stations.


If you can think of a “dream industry” to work in, what would it be? If you want one that will have expotential growth over the next 20 years think oil and gas. Unlike the growth of hamburger stands in the 60s, oil and gas jobs pay very well. Walk into Midland Texas with no experience and get a job as a “roustabout” (a common laborer) and you’ll make $40,000 to $50,000 – and that is the bottom of the ladder.

The best part about pipe and pipe welding:

The oil and gas industry is the biggest employer of pipe welders. The growth of natural gas utilization means enormous amounts of pipe must be welded. The American Welding Society or AWS sets the standards for welding. Way back in 2007 they said, “The average rig pipe welder in Alberta Canada makes $330,000 a year.”

I recently spoke to a welder who went one step further contracting repairs with a refinery in 2013. He made $400,000 in 2013.

What is the bottom line?

Welding and the oil (and particularly natural gas) present an exciting fast growing opportunity that can make anyone with some moxy and get up go rich in the coming years – regardless of the condition of the rest of the economy. Is that why North Dakota has 2.6% unemployment? Did you know Midland, TX has 2% unemployment? Did you know that 5% unemployment is considered “Full Employment” because 5% of the work force should not be working? These numbers are stunning – they are incredible.

The USA must go through another deep recession. to wash out the debt that is keeping the general economy down. Many areas of business we now think of as “bullet proof” will shrink or disappear. The DOW will probably sink to 5,000 by 2016 or 2017 – but naturals gas will stay strong which means pipe welding jobs will be plentiful, even during the next recession.

What should you do next?

You can SKIP welding school and teach yourself to be a 6G pipe welder at home, in eight weeks or less, even if you have never welded in your life. Discover the secrets revealed in: “The $100K Welder” eBook and course will give you step by step instructions. Check out: Look, go to my website, sign up for my free newsletter about pipe welding – and call me on my personal cell. Tell me about you. I’ll help you figure out your next career move – and I promise – I mean it – I WILL NOT sell you anything! It is FREE! Talk to me for 20 minutes – it can change your LIFE! No, I am NOT going to change your life – your life may change because of the information I will share with you – it is that simple.

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Welding Jobs: Why Welding Sucks (And What You Can Do About It)

Welding Jobs: Why Welding Sucks (And What You Can Do About It)

If you can weld now or want to weld, is that a big deal? Yes and no.

Welding can be a very difficult skill to acquire and take years – or an afternoon (or a few days) at home. The question is, are you making any stinking money at it? Yes, you love to weld (I do to). Why are some welders rolling in money and others are so broke it isn’t funny? Get answers, NOW.

Let’s see, anyone can pop into Home Depot and buy a little Lincoln flux core welder and learn to weld in an afternoon or a day or two? Yes.

The welder I’m referring to is about the size of carry-on luggage and plugs into any 120 volt socket. Follow the instruction booklet (always reading the safety portion and applying all of it – please) and that person can be running a decent bead on the flat, just like that. Really – in a few hours of paying attention you can be running decent beads with good penetration.

The REAL question is, can you take that skill and make money?

Think about it – you can read this article, hop in the car, buy the welder, plug it in and weld for a few hours and have a “skill” at some level. What does that make you? It makes you a person with a very limited skill, but a skill none-the-less.

When I was 13 I welded up the exhaust on one of my many cars (I flipped cars for profit from age 11 to 22). Welding came in handy on older cars from the early 60s and even the early 50s because they were “heavy metal.” I wasn’t a great welder at that point, but being able to weld could make the difference – it allowed me to do repairs and “add value” to a car. Instead of flipping burgers at Mickey Ds, I was able to always have plenty of money.

Later, at age 19 and just out high school, I built gates – nice gates which look great today, 40 years later. I was self-educated in welding and I highly recommend it (welding self education and self education for almost any skill).

So why is the title of this article: “Welding Sucks?” Well, for most welders, it sucks. It is not fun when you get stuck with a limited skill in a factory not making enough money and acting like a robot all day long.

What can you do to make welding fun again?

When you first started welding, it was fun. You didn’t need to make money at it right away. AND everyone around you told you there would be a “good job” waiting for you when you got good at welding – so you kept at it.

Maybe you went through one or two years of welding education – and then the truth hit you like a brick wall. You found out that no one wanted to pay you big money for welding…

What is the secret?

What is the well guarded secret no one seems to tell welders? It is marketing. If you can MARKET your skill – no matter what that skill is – if your skill is welding or washing windows, if you can MARKET that skill, you will make all the money you and your family need. If you can’t, you won’t. That is when welding is NOT fun – when you can’t make good money at it.

What can you do about it?

Step # 1:

Stop thinking “Job.” J-O-B stands for “Just Over Broke.” If you want to live your life that way, get a job or keep the one you have.

What is the difference between a window washer working for someone else and window washer making great money for 28 years?

I met Suzy the other day. Suzy lives in a waterfront home with a dock. Suzy has a new GMC 4 door truck (very nice). Suzy no longer bothers to advertise her business. Suzy has been cleaning windows as an independent window cleaner for 28 years. She doesn’t need to advertise.

Why am I telling you about a window cleaner?

Suzy became an INDEPENDENT window cleaner 28 years ago. She employs 3 window cleaners and pays each of them $10 an hour. Suzy collects $20 an hour for every hour her window cleaners work. Suzy also runs a fourth truck herself. Add it up – Suzy makes $30 an hour from her workers and she makes another $20 an hour for the hours she works. Suzy makes $100,000 a year washing windows. This is called “Capitalism.”

Why do you need to be a Capitalist?

We live in a capitalist society. This means that if you weld now for $10 an hour, you can weld as an independent welder for $30 an hour (or more) simply by being “in business” instead of being a “a working drone” for someone else. Is that hard to believe? Believe it – it is simply TRUE!

$30 an hour is cheap for a welder.

I am telling you – you can make $30 an hour next week with minimum welding skills, if you understand and apply basic marketing skills.

What about immigrants? Meet Tom:

Tom (not his Viet Namese name) is one of the nicest people I have even encountered. Tom is 60. In 1980 Tom was one of 25 people crowded on a small fishing boat pulling away from Communist Viet Nam and headed for Hong Kong – escaping at the risk of his life – to a new life of freedom.

The captain of the boat put a gun by the compass. It screwed up the compass. They were lost at sea. They ran out of gas. They ran out of food. The seas grew wild. Tom was pretty sure they were all going to die.

They saw a ship in the distance. They waved their coats. They were given food and gas told which way to go to reach Hong Kong. Tom made it to the U.S. Tom was totally and completely broke – and he spoke no English.

Working an assortment of jobs 15 hours a day, Tom saved money. He met Lany and they saved. They opened a nail salon and then another. Today, Tom and Lany are comfortable in America. Their home is nearly paid for and they have a large retirement. Why? Tom and Lany worked hard – and understood marketing. And yes, they had a skill – they started by becoming licensed to do nails. Can you see – “doing nails” was only part of their of their success – actually the small part.

What has this got to do with welding?

Everything! However, welding has so many advantages over window cleaning and doing nails! You can start right now and be an entry level welder, working for yourself a week from now, if that is what you want. Unlike window cleaning and nails, you can advance your welding skills as you go – teaching yourself from home – until your welding skills are worth (are you sitting down) $100 an hour.

Don’t run over to Home Depot and buy a welder (yet).

If you buy the right welder used and do the right things with marketing, you can be in business and working all you want in 2 to 3 weeks. How? It requires mastering a few marketing basics – and hard work – but if a Viet Nam boat person who could not speak English can do it, you can too.


You success has nothing to do with money or the economy. It has to do with you believing in you. From there, you only need to pay attention to what really matters.

What should you do next?

Look – are you a person? I am too! I am a welding inspector who now writes. I also have made millions in small business. So what? Well, I’m offering 20 minutes on the phone or in email with me – and I won’t sell you anything – it is all free. It will be 20 minutes that could change your LIFE! It is FREE! I won’t bite – promise! Go to the website below and call me – Click HERE: – you have NOTHING to lose and everything to gain – it doesn’t matter if you weld now or not – I KNOW I can help you. I have 70 unsolicited testimonials – you can view those at: – but just call me! It’s FREE!

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Gas Welding Technology

Gas Welding Technology

Gas welding is a process in which a fuel gas such as acetylene, hydrogen, natural gas, etc. is mixed with oxygen in proper proportion to burn to get a flame which, if found adequate for melting a given metal, can be used for fusing and joining different parts of it. The process is very versatile because it can weld most of the commonly employed engineering metals and their alloys. Brief description of the well known variants in this class of welding processes follows.

Oxy-Acetylene Welding

This is the best known gas welding process and was successfully employed first time in 1903 when a welding torch for the purpose was developed. In this process acetylene (C2H2) is mixed with oxygen in the welding torch and is then burnt at the torch tip to give a flame with a temperature of about 3300oC which can melt most of the ferrous and non-ferrous metals in common use.

Oxygen and acetylene are easily available in cylinders at temperature of about 1500 N/cm2 and 170 N/cm2 respectively. These are connected to the welding torch through hoses and are mixed and burnt to get different types of flames viz., neutral, oxidizing and carburising. The natural of the flame depends upon the ratio of the two gases. The neutral flame is most often used for the welding of most of the materials like low carbon steels, cast steel, cast iron, etc. The oxidising flame has higher proportion of oxygen than acetylene and is used for welding of manganese steel, brass and bronze whereas the carburising flame has higher proportion of acetylene in it and is used for welding aluminium, nickel, etc.

It is quite common to use filler material with gas welding through if need be, the process can be used without filler as well. Commercially, oxy-acetylene process is very widely used for welding of ferrous and non ferrous metals particularly for welding thin sections upto 6 mm. A large percent of the repair work is also done by oxy-acetylene welding.

Typical applications of the process include welding of root run in pipe and other multi-run welds,, light fabrications like ventilation and air-conditioning ducts and motor vehicle repairs.

Oxy-Acetylene Pressure Welding

In normal or non-pressure oxy-acetylene welding process no use of pressure is made to accomplish a joint. However, in slight variant of the usual process, the prices to be joined are heated by oxy-acetylene flame burner and brought to the pasty or semi-solid state. Axial pressure is then applied to achieve a joint which is normally of an upset weld type. No melting of the parts being welded is involved hence it is a solid-state welding process and is also called ‘Hot Pressure Welding’ or simply as ‘Gas Pressure welding’.

The ends of the work piece to be welded are prepared by cutting and cleaning. The pieces are then held in clamps under an axial pressure of about 3.5 to 7.0 n/mm2 for mild steel. An oxy-acetylene torch or a heating head of the desired configuration is made to surround the abutting (or projecting) ends and heated uniformly to about 1200oC. During the heating cycle the pressure is increased to the desired lengths of the two pieces. This is also prevents the possibility of local overheating or superficial melting.

Oxy-acetylene pressure welding can be used to weld all commercial metals which can be butt welded, however, presently it is used mainly to weld carbon and low alloy steels in the form of rods, rails, pipes, tubes, narrow strips, and structural shapes. In general, those materials which absorb their own oxides at elevated temperature, e.g. low carbon steels, are more easily welded by this process. However, this process finds only a limited use in the industry because it is uneconomical to use it for one-off work as well as due to lack of uniformity and consistency of components produced by the process.

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Basic Function of Semiautomatic MIG Welding Machine

Basic Function of Semiautomatic MIG Welding Machine


Functioning a satisfactory MIG Welding process requires more than just semi operative skill. The setup, voltage, current, electrode extension, and welding angle, as well as other factors, can dramatically affect the weld produced. The very best welding conditions are those that will allow a welder to produce the largest quantity of successful welds in the shortest period of the time with the highest productivity. Because these are semiautomatic or automatic processes, increase productivity may require only that the welder increase the travel speed and current.


In complete MIG welding machine setup, we require GMAW or MIG power source, welding torch, wire feeder unit, shielding gas supply, gas regulator, flow meter & heater, shielding gas hoses and MIG wire.

If the shielding gas supply is a cylinder, it must be chained securely in place before the valve protection cap is removed. Standing to one side of the cylinder, quickly cracked the valve to blow out any dirt in the valve before the flowmeter regulator is attached.

Install the reel of electrode (welding wire) on the holder and secure it. B sure the power is off before attaching the welding cables. The electrode and work leads should be attached to the proper terminals. The electrode lead should be attached to electrode or positive (+). If necessary, it is also attached to the power cable part of the gun lead. The work lead should be attached to work negative (-).


Using the MIG Welding Machine that was properly assembled, we need to turn the machine on and thread the electrode wire through the system. Switch on the power and check the gun switch circuit by depressing the switch. The power source relay, feeder relays, gas solenoid and wire feeder motor should all active.

Cut the end of the electrode wire free. Hold it tightly so that it does not unwind. The wire has a natural curve that is known as its cast. The cast is measured by the diameter of the circle that the wire would make if it were loosely laid on a flat surface.

Note: With the wire feeder running, adjust the feed roller compression so that the wire reel can be stopped easily by a slightly pressure. Too light a roller pressure will cause the wire to feed electrically. Too high a pressure can turn a minor problem into a major disaster.


Density is the chief determinant of how effective a gas is for arc shielding. The lower the density of a gas the higher will be the flow rate required for equal arc protection. Flow rates, however, are not in proportion to the densities. Helium, with about one-tenth the density of argon, requires only twice the flow for equal protection.


The arc-voltage and amperage characteristics of MIG Welding are different form most other welding processes. The voltage is set on the welder, and the amperage is set by changing the wire feed speed. At any one voltage setting the amperage required to melt the wire must change as it is fed into the weld. It requires more amperage to melt the wire the faster it is fed, and less the slower it is fed.


Because of the constant-potential (CP) power supply, the welding current will change as the distance between the contact tube and the work changes. Although this change is slight, it is enough to affect the weld being produced. The longer the electrode extension the greater the resistance to the welding current flowing through the small welding wire.

With a standard MIG Welding CC power supply this would also reduce the arc voltage, but with a CP power supply the voltage remains constant and the amperage increases. If the electrode extension is shortened, the welding current decreases.


The term welding gun angle refers to the angle between the MIG Welding gun and the work as it relates to the direction of travel. Slight changes in the welding gun angle can be used to control the weld as the groove spacing changes. A narrow gap may require more penetration, but as the gap spacing increases a weld with less penetration may be required. Changing the electrode extension and welding gun angle at the same time can result in a quality weld being made less than ideal conditions.

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Welding Types and Welding Rods

Welding Types and Welding Rods

Welding is the process of heating two pieces of metal so that they join and form a firm joint. To do this, one needs a high degree of skill and technology. There are different ways of welding; some require machinery and advanced technology, including lasers, beams, etc. Welders work with metals, alloys and materials.

Oxy-Acetylene Welding is a welding process that requires the use of a special welding torch to mix oxygen and acetylene gases and produce a small flame of up to 6,300 degrees. This process is widely used to manufacture wrought iron gates and fences. This type of binding is normally used in industries that work with copper pipes, including brass wear plates and brass rods.

Gas Cutting Using Oxy-Acetylene

Most of the gas torches have a lever style valve that facilitates an extra burst of oxygen through the cutting torch to the work that has been heated to melting point. This shot of oxygen burns away the parent metal with high force and speed, thus producing a small narrow cut in the metal. This way, welders can cut easily, either manually or by machines. Manual gas cutting can cut metals of 1/16 of an inch and up to two inches, while profile cutting can cut steel up to a thickness of four inches.

TIG welding

Tungsen welding or TIG welding uses a non-consumable tungsten electrode to create the weld. The weld area is protected by an inert shielding gas and a filler metal is normally used. This type of welding is usually used to thin sections of stainless steel and metals like aluminum, copper and magnesium.

Plasma arc welding

In plasma arc welding, the electric arc is formed between an electrode and the work piece. The process is similar to TIG welding.

Laser Beam welding

Laser Beam welding is a meld technique where multiple pieces of metal are joined through the use of a laser. This type of welding is often used in high volume applications, such as in the automotive industry.

Welding rods

Welding rods of good quality should be bought, so that the welding result is better. Welding rods are used to place additional metal to the weld. Hence, it needs to suit the parental metal. Welding wire and oxy-acetylene rods are mostly made of Norway steel. Choosing the right welding rod is important as it helps to determine the success of a weld and the strength of a joint. If you choose the wrong rod, it can produce a meld that is either too hard or brittle.

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