Oxford Tig welder plus welding tips: Stick Welding — If you learned to weld years ago, you likely learned using an arc welder. Stick welding for many years has been the most popular method for most home-shop welding needs. This process uses an electric current flowing from a gap between the metal and the welding stick, also known as an arc-welding electrode. Stick welding is an effective method for welding most alloys or joints and can be used indoors and outdoors or in drafty areas. It’s also the most economical welding method and provides the ability to create an effective bond on rusty or dirty metals. However, this method is limited to metals no thinner than 18-gauge, requires frequent rod changing, emits significant spatter and requires that welds be cleaned upon completion. Stick welding is also more difficult to learn and use, particularly the ability to strike and maintain an arc. Arc welders are available in AC, DC or AC/DC, with AC being the most economical. It’s used for welding thicker metals of 1/16 inch or greater. These machines are a good choice for farmers, hobbyists and home maintenance chores.
The power electronics have to work at the mains input voltage which is in excess of 630V on a three phase machine & in excess of 340V for single phase with peak voltages often in excess of 800V. This is not an easy task for any electronic mosfet or IGBT & in most machines there are multiple IGBT’s or mosfets all working together. Then when you add real welding conditions such as damp & dust, voltage fluctuations & spikes it just becomes a matter of time before a failure occurs. Some of the quality US & EU manufacturers have tried to address this by designing machines with separate compartments or wind tunnels to keep critical componants away from dust & damp etc. This has improved reliability in some cases, however by nature all inverter based machines are fairly fragile. Furthermore inverters are increasingly using complex microprocessors, computers are fine on a desk but in a dirty welding machine? More problems! However inverters do you have a place, if you need a machine where portability is the number one priority then consider a quality EU or US made inverter but keep it simple, more complex functions often means more to go wrong! Find more details on Oxford Plasma Cutters.
Improper drive roll selection and tension setting can lead to poor wire feeding. Consider the size and type of wire being used and match it to the correct drive roll. Since flux-cored wire is softer, due to the flux inside and the tubular design, it requires a knurled drive roll that has teeth to grab the wire and to help push it through. However, knurled drive rolls should not be used with solid wire because the teeth will cause shavings to break off the wire, leading to clogs in the liner that create resistance as the wire feeds. In this case, use V-grove or U-groove drive rolls instead. Set the proper drive roll tension by releasing the drive rolls. Then increase the tension while feeding the wire into your gloved hand until the tension is one half-turn past wire slippage. Always keep the gun as straight as possible to avoid kinking in the cable that could lead to poor wire feeding.
One of the “cardinal sins” that almost every shop commits is over-welding. This means that if the drawing calls for a 1/4″ fillet weld, most shops will put down a 5/16″ weld. The reasons? Either they don’t have a fillet gauge and are not exactly sure of the size of the weld they are producing or they put in some extra to “cover” themselves and make sure there is enough weld metal in place. But, over-welding leads to tremendous consumable waste. Let’s look again at our example. For a 1/4″ fillet weld, the typical operator will use .129 lbs. per foot of weld metal. The 5/16″ weld requires .201 lbs. per foot of weld metal – a 56 percent increase in weld volume compared to what is really needed. Plus, you must take into account the additional labor necessary to put down a larger weld. Not only is the company paying for extra, wasted consumable material, a weld with more weld metal is more likely to have warpage and distortion because of the added heat input. It is recommended that every operator be given a fillet gauge to accurately produce the weld specified – and nothing more. In addition, changes in wire diameter may be used to eliminate over-welding. Explore even more details at www.weldingsuppliesdirect.co.uk.