Learn Welding

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Home Welding

In this article we will be looking at home welding and what type of decisions the beginner needs to make, and we shall be looking at the welding processes in a little more detail to find their strengths and weaknesses to tailor them to the home welder looking to buy a welder for themselves. All welding processes work in the same basic way which is to heat a metal to a specific heat to melt the edges of the metal and have some form of filler metal added as different processes do this in different ways to give different results.

In all cases we have to exclude air from our welds as any air introduced into a molten weld pool creates a problem called “oxidation” which is basically a form of rust, within the weld which weakens it. We also suffer from other forms of contamination within a weld and this is generally pockets of any other rubbish or holes in the weld which are voids of gas or air which we call “porosity” which weakens a weld, and the general term used for any contamination within a weld are called “inclusions” as this is a generic term for a defective weld. We shall discount gas welding as this requires two gas bottles to be rented on a monthly or yearly account and you have to pay for the bottles to be filled and this is expensive for the home welder, particularly if they want a machine for simple repairs.

Arc or stick welding – this is the cheapest form of home welding as all you require is a welder complete with its welding leads and a box of arc welding rods to begin welding, and you will need an appropriate head shield with a suitable shade of filter fitted, and welding gauntlets are a good idea.
Arc welding for home use will usually be using a transformer based welder as they are cheap and extremely robust in construction as they are the simplest form of welder, I still have my first welder and it is a SIP and nearly 40 years old and still going strong.
Most welding transformers will work your mains electricity hard so the first thing you need to look at is the incoming current or amperage it needs, the mains domestic supply will provide you with 13 amps of mains power so never buy a welder whose incoming amperage requirement exceeds this. If you do exceed this you will burn out your house wiring and wear out your plugs and sockets at an alarming rate, so any welder requiring more than this 13 amps input will need an upgraded wiring system suitable for the load it is carrying along with a slow blow fuse in the fusebox.

Your welder will supply something called AC voltage as it has AC mains voltage coming into it and it transforms this voltage down and will supply AC voltage out to your electrode or welding rod, and many electrodes will require an AC voltage to them, some will work with both AC and DC voltage. Electrodes come in many forms and types and the best type to use is something called the E6013 electrode as this is a general purpose electrode for welding mild steel, other numbers are available and the 7018 is a low hydrogen or hydrogen controlled electrode designed for tougher steels. 6013 electrodes are designed to weld in all positions including welding downhill and are by far the easiest rod to learn with; as your skills improve you can swap for other types of electrodes and try welding with them.

Electrodes are basically a metal wire core of a designated thickness which determines their size, a 2mm electrode will have a 2mm diameter wire, and this is covered with a flux which is simply a powdered form of clay which is impregnated with various compounds. As you strike an arc the clay flux melts into the molton metal of the weld along with the wire core and it attracts anything but the metal and floats to the top of the weld, it brings anything in the weld up to the surface of the weld and holds it in something called the slag and it hardens. When your weld is fully hardened this slag is simply chipped off and all the weld contaminants go with it; your electrode coating also forms a shielding gas over your weld to exclude air as you weld, so never use an electrode which has a damaged flux coating as it will stick to your weld pool and not shield your weld or lift out any inclusions.  

Electrodes come in many sizes and the larger diameter the electrode is the more current it needs to consume to weld effectively, and all electrodes have a welding current range. For home welding the electrodes come in 1.6mm, 2.0mm, 2.5mm, and 3.2mm  diameter and the largest current you can reasonably expect from 240v mains power supply is around 140 amps from your welder, and the larger electrode you have, the more current you need, and the shorter the welding time you have before your welder trips out on thermal overload.

Pro’s

Cheapest form of welding with plenty of different types of electrodes easily and readily available.
Simple and robust transformer machine with little to go wrong.
Infinitely variable power output.
Tolerates a degree of contaminated metal, but always clean as much as possible.
Can weld outside in windy weather with it.

Con’s

Will not weld thin sheet metals such as vehicle bodywork.
Limited welding times with larger electrodes.
Electrodes need to be kept dry and the flux coating needs keeping free of chips.
Beginners often apply too much power to the electrode they are using to make arc striking easier.


MIG welding is currently the “in vogue” welder to have and many people simply buy them for vanity to say they have the latest welding machine, but a MIG welder is exactly the same as the arc welder in its transformer as it produces an AC power output. Where MIG welding differs is that between the transformer and the output they have something called a “rectifier pack” which is a series of power electronics called diodes which convert the AC output of the transformer to a DC power before it reaches the business end of the welding machine? Therefore we can conclude that all small MIG sets are DC machines as they use DC current to weld with.
MIG welders differ in that you replace the electrodes with a spool of welding wire which is inside the machine and has a set of drive rollers which pull the wire from the spool and feed it into a liner in the umbilical, you have no shielding gas so you have to rent a bottle of shielding gas to shield your weld.
Drive rollers are rollers with grooves machined into them and the two sizes of wire for domestic MIG welders are 0.6mm and 0.8mm and you have to fit your drive roller with the correct groove for the size of wire you are using. You will have wire tension settings to set the tension on the drive rollers for the welding wire as it is squeezed between them, and a separate tension to set the tension or resistance of the spool of wire to stop it unravelling itself when you stop welding.

From your machine you will have something called an umbilical which contains several components in a common housing. You will have a power wire to take the DC power from your welder to the contact tip, you will have a thin silicon tube or pipe to take the gas from your machine to your welding gun, a liner into which your welding wire is fed to go to your gun, and a pair of wires from the switch on your welding gun back to your machine.
On the other end of your umbilical you have your welding gun which has a trigger, a brass internal housing, a gas diffuser, and a contact tip which your welding wire runs through and passes the welding current to your MIG wire; you will also have a shroud which either pulls or screws off to force your shielding gas around your welding wire and the weld.

On the front of your machine you will have several switches; one will be a rotary power switch with several positions and you turn this to increase your power, this is a stepped power switch as you can only have the power settings dictated by the position of this switch. Next is another rotary switch which is infinitely variable and this increases your wire feed speed and this is matched to your power output and the type of material you are welding, you may have latching push switches instead of a rotary power switch. In some cases you may have something called a euro connector which is a plug on the end of the umbilical which plugs in one way and has a screw collar to hold it to your machine.
As you pull your trigger it sends power back to your machine and this activates the gas valve to open it and allow gas to flow into your umbilical, it powers the feed motor which drives your wire feed rollers, and it activates your transformer to provide welding current.

Straight away you have costs as you have to rent a bottle of shielding gas and pay to have it filled, you have numerous consumable items such as contact tips, umbilical liners, drive rollers, and shrouds as they all wear out quickly, and they are an additional cost. MIG welding only works on clean metals so an angle grinder with numerous discs to clean any metal is an additional expense, along with its consumables, but MIG has benefits such as being able to weld thin steels such as car bodywork; but a basic MIG welder will only weld steel and stainless steels.

Pro’s

Will weld thin sheet metal such as car bodywork.
Can be used with a pub CO2 bottle with the appropriate adaptor, to save on bottle rental.
Much faster welding on materials of longer lengths.


Con’s

Costs of consumables.
Cost of renting a shielding gas bottle and the purchase of a suitable regulator.
Cost of disposable shielding gas bottles if they are used.
Limited thickness of material they can weld for their size.
All metals need additional work to clean them before welding.
Costs of an angle grinder, and their consumables to clean material.
Not suitable for welding outside as shielding gases are blown away from the weld by winds.
Welding wires need storing in a house to prevent corrosion between welding as corrosion affects the wire feed and chews up the inside of the liner, and jams in contact tips.

Note – no gas MIG welders have come onto the market and are very popular and they have a flux cored wire which is extremely expensive and its fumes cause health problems as basically they are toxic and hazardous to health. Gasless welding machines have been banned in industry in the European member states due to these emissions and their associated health risks. If you decide to ignore the health risks and by one you will find that flux core wire comes in 0.9mm diameter and this requires you to purchase an additional wire drive roller and additional contact tips to handle wire of this diameter, and they eat through contact tips.


Selecting a welding machine – if you intend on working with a high proportion of sheet metals then MIG is the best machine if it is very thin sheet metal such as the 0.7mm thick car body steel, if it is above 1.5mm thick sheet steel then arc welding is a much cheaper and more convenient way of welding.

If you do repairs to gates, wrought ironwork around the home, or intend to undertake basic fabrication then arc is the much better option as it will tolerate dirtier metal much better than MIG, if you have a limited budget then its arc by a country mile. If you work inside then MIG is a viable option as its shielding gas cannot be blown away, if you work outside then arc wins again. Only you can decide which type of machine to buy and selecting the right machine for your purposes is crucial.

Welding Safety – always wear a welding headshield with the correct filter fitted, filters come in a number of shades ranging from number 9 to number 13 for general welding in either arc or MIG and they generally have a clear plastic or glass on the outside of the filter to protect it from sparks.

Always cover up when welding, wear cotton clothing such as jeans or overalls and boots, cover the tops of your boots with your trousers to prevent sparks going inside your boots, always wear long sleeved shirts with a tight fitting neck as any exposed skin will quickly burn and many have had the welders V on their necks. Welders V is where someone wears a V necked shirt and the top of the chest and bottom of the neck turn a very bright red through exposure to the intense infra-red emissions from the very intense light welding emits. Always avoid wearing man-made or synthetic fabrics as the heat from welding can melt them onto your skin and cause serious burns to your skin and this is to be avoided.

Always be aware of your environment, never work in places such as sheds or other wooden structures, particularly those with wooden floors as welding spatter and even blobs of molten metal can roll or drop onto the floor and ignite such structures. Be aware of flammable products such as fuels, thinning agents, paint brush cleaning agents, oils, or anything else flammable in the vicinity of welding operations, particularly those in plastic containers as a single spark can melt through the container and ignite the contents.
Never work without a head screen and never let anyone else in the vicinity of your welding watch you and this includes children and animals as the intense glare from welding causes a condition known as “arc eye” in which the light burns the retina of your or their eyes, and it is painful. Children and animals love to watch welding and do so while totally unaware of the dangers.

Be aware of what you are welding, if you are welding a vehicle and it is an enclosed or box section then it could be full of rust preventative solutions such as Waxoyl and this is highly flammable and once it ignites it is almost impossible to put out. Most vehicles have corrosion protection on their undersides and if you are welding in a floor repair section this can also ignite without you knowing about it, similarly, if you are welding from the underside of a car you may ignite any sound insulating pads or carpets if they are not removed, or god forbid you ignite any wiring stuck to the floor.  

Home welding opens up a whole new avenue for the home fabricator and even the home repair shop or facility as with a little knowledge you can learn to weld many things and this opens up avenues in repairing things as well so you can extend their working life. Fabrication is affected as it opens up new fabrication possibilities for the fabrication of something new from waste metals or simply reduces the need to drill and bolt something together, you can hard face working edges of tools to improve their working life with the correct rod and a little experience. It allows you to recycle metal waste items into new and useful items and is something everyone looking to becoming more independent should develop as a new skill.