Welding tips to make it stick until the next time

Welding is a hugely valuable skill for a farmer have. It can solve many minor issues before they develop into major problems.

Investing in the correct hardware and health and safety equipment can facilitate repairs to gates, crushes and machinery, saving time and money.

There are many different ways of welding, or fusing metal together. By far the most common and versatile method found on farms is arc or stick welding. The correct description for this is manual metal arc welding (MMAW).

The electrical power of the welder generates an electrical arc between flux-coated welding rods and the items being welded.

Effectively, the arc melts the welding rods and work piece together, consuming the welding rods in the process.

On the farm, not much is needed to carry out stick welding. A decent electrical power supply is about it. There is no need for gas bottles or a three-phase electrical supply, so it is simple to get set up.

If either purchasing a welder for the first time or upgrading an existing unit, there are a huge number of options.

One way of classifying a welder’s size is by how much amperage it can generate at a given duty cycle – the number of minutes out of a 10-minute period a welder can operate.

For example, if a unit can deliver 150 amps of welding output at a 60% duty cycle, it can weld continuously at 150 amps for six minutes, and then must cool down during the remaining four minutes to prevent overheating.

Picture 1

Pictured here are three of the most common AC welders found on Irish farms (DC units are available, but tend to be for more specific, professional use).

On the left is an oil-cooled 180amp unit, typically priced around €1,000. This will weld all day long without a problem, but because it is oil-cooled it is not very portable.

In the middle is what is called an inverter welder. Using some smart electronics, this type of unit is very light, portable and powerful. Pricing varies from around €225 for a 140amp unit to around €495 for a 200amp unit.

On the very right is a small air-cooled unit, ideal as a starter or hobby machine.

Picture 2

Tools of the trade include welding gloves, safety glasses, chipping hammer and wire brush. The welding gloves provide protection from the extremes of heat, ultraviolet light and sparks.

Safety glasses are essential and must be worn when chipping slag off the weld or wire brushing. The wire brush helps clean the metal before and after welding.

Overalls form an important part of an individual’s personal protection equipment when welding. But not just any overalls will do.

Ideally, you are looking for 100% cotton or fire-retardant welder’s overalls. Polyester or polyester cotton mix will not do, as they melt too easily under heat or flame. There is a huge amount of protective clothing available for professional welders, from leather aprons, leather sleeves, hoods, spats, coats and more.

Steel toe-cap boots are essential when working with a welder.

There are a number of welding mask options, from basic handheld and head-worn flip up/down shields to modern reactive head-worn units.

A handheld mask is not ideal, because you have to use one hand to hold it.

Head work is a better option and if the budget allows, a reactive welding helmet is the best option. A reactive helmet automatically darkens as soon as light from the welding arc hits it and lightens as it ceases.

The welding rod is flux-coated, which protects the molten weld as it forms from contaminants in the atmosphere.

The range of welding rods available is enormous – rods for vertical welding, combination welding, different metals, hard-surfacing, gouging and more.

For general agricultural use, general-purpose mild steel rods of 2.5mm and 3.2mm (12 and 10 gauge) thickness will do for most applications.

Picture 3

When making a horizontal weld on a flat surface, keep the sides of the welding rod perpendicular to the job.

The angle of the rod is typically 10° to 30° from the vertical position and dragged in that direction to lay off a weld, with the slag forming on top of it as it is produced.

Picture 4

Position the earth clamp as near as possible to what you are welding and make sure it is making a good contact.

Pictured are a war-weary clamp and a new clamp. Starting a welding rod off, to get it to arc (spark) can be tricky for a novice.

It is a bit like striking a match, and is one of many skills to learn on the road to becoming a competent welder.

Once the arc is struck, it is a matter of maintaining the gap between the welding rod and work piece.

Too close and the rod will stick – twist to break it away. Too far and weld spatter goes everywhere.

Just right and you will hear a noise or crackle, similar to rashers frying on the pan.

The trick is then to maintain that same distance and crackle while the rod burns away as you simultaneously drag the rod along to create the perfect weld. It takes a lot of practice and patience to get right.

Picture 5

This example was created using 3.2mm welding rods. The furthest away weld was at too low an amp setting. This created a ridge-like weld with little or no weld penetration plus slag under the weld.

The nearest example is where the amp setting was too high. This produces a flat weld, which is a dull grey or even black, resulting in a weakened weld.

The weld in the middle is about right, shiny and shaped well with (probably) the right amount of weld penetration if we did a cross-section cut of the sample.

Picture 6

An indicator of a good weld is where the weld slag either peels away altogether or lifts and crack like in this picture.

You need very little chipping with the hammer to clean the weld slag off.

Again, spend some time practising on the flat to develop the right technique and knowledge of welding.

Tips

Store welding rods in a dry place – even the hot press if you can. Damp rods do not work well, if at all, and can be money down the drain.

Welding consumes a lot of power from your ESB transformer and will cause lights to flicker, especially if it supplies more than one house.

Some welders take quite a surge of power to start a welding rod. If this persistently causes the miniature circuit breaker (MCB) protecting your welding socket to trip, despite the amperage rating being correct, then your electrician may change the MCB for one with a higher curve rating.

Health and safety

Heat and fire – molten metal and molten weld splatters will easily set hay, straw, plastic, cardboard, fuels and paints on fire.

Heat and burns – The welding process by its nature heats up metal to melting point. Human skin and flesh is very vulnerable and burns are extremely painful. Take proper care while using a welder and make sure work pieces are secure. A clean supply of running water is essential for treating burns. Run cold water on the affected area for 10 minutes to cool it, and seek medical advice.

Electrocution – Molten metal or red-hot work pieces will melt the main supply cable if they come into contact with it, creating an electrical hazard. Be aware of cable positions and ensure work pieces are secure. Ask your electrician to check that your installations are correct.

Fumes – The welding process will produce fumes. If you feel you are being affected by these, then cease immediately. Welding anything painted or galvanised will produce considerably more noxious fumes, so either avoid altogether or take appropriate action to reduce the risk. If a lot of welding work is carried out on the farm, an extraction system could be considered.

UV and IR – The welding process produces both ultraviolet and infrared light radiation. Use a suitable welding mask with the correct light filter to protect your eyes. Never look at the welding process with the naked eye. In the short-term, it can result in a very irritating and painful condition called arc eye. In the long-term, overexposure can damage eyes permanently.

Other considerations

Pacemaker: A welder and the welding process produces electromagnetic energy that could interfere with a pacemaker. So, if you have a pacemaker fitted, check with your doctor or specialist to see if it is safe to operate or even be near a welder.

Contact lenses: There has been much talk over the years about the use of contact lenses while welding. There are even more discussions on the internet, but the following extract from the Canadian Centre for Occupational Health and Safety sums it all up in a common sense manner: “The CSA Standard W117.2 states that contact lenses should not be worn by welders and welding personnel. Contact lenses do not provide protection from ultraviolet radiation and flying objects. All workers in proximity to welding procedures must wear appropriate eye protection according to the circumstances.”