The MiG is (apart from the spot welder) arguably the easiest of welding devices for the beginner to use for general bodywork repairs. This does not, however, mean that it is an easy matter to produce clean and strong welds on typically thin body panels for, unless conditions and the user's skills are both excellent, there are many obstacles to good welding.
The worst problem to beset the novice is that of 'burning through', when the electric current melts straight through the metal which it is supposed to be joining. This can occur if the wire feed speed is too slow (or intermittent, which indicates a fault in the welder — usually either the wire jamming in the liner or the driving wheels slipping), if the gun is moved across the metal too slowly, if the current is set too high or if the shielding gas/core fails to do its job.
When the metal to be welded has become thin through rusting then the chances of burning through are greatly increased, and hence the advice to always cut back to not only clean but also to strong and thick metal before attempting to weld.
The correct preparation of the metal which is to be welded is vital. All traces of rust, of paint, oil, grease and any other contaminant must be cleaned from the surface to avoid poor adhesion and spiting. Any impurities which find their way into the welded joint will substantially 11 Taken it.
When a joint is being welded, both surfaces should be thoroughly cleaned; if paint or any other contaminant is present on the underside of the panel then it will mix with the molten weld/steel and weaken the joint. Recently, special paints have become available which can be used on surfaces which are to be spot or MiG welded. The use of these products — such as 'Autoline' weldable zinc primer, will ensure that the welded joint does not — as is normal — become the first part of the repair to rust through again. The metal panels must then be clamped in some way so firmly that the heat of the welding process does not distort either of them and allow them to move apart. Small sections may be clamped using mole grips, although longer runs are usually affixed using self-tapping screws or alternatively pop rivets at regular intervals. the joint. Recently, special paints have become available which can be used on surfaces which are to be spot or MiG welded. The use of these products — such as 'Autoline' weldable zinc primer, will ensure that the welded joint does not — as is normal — become the first part of the repair to rust through again. The metal panels must then be clamped in some way so firmly that the heat of the welding process does not distort either of them and allow them to move apart. Small sections may be clamped using mole grips, although longer runs are usually affixed using self-tapping screws or alternatively pop rivets at regular intervals.
The worst problem to beset the novice is that of 'burning through', when the electric current melts straight through the metal which it is supposed to be joining. This can occur if the wire feed speed is too slow (or intermittent, which indicates a fault in the welder — usually either the wire jamming in the liner or the driving wheels slipping), if the gun is moved across the metal too slowly, if the current is set too high or if the shielding gas/core fails to do its job.
When the metal to be welded has become thin through rusting then the chances of burning through are greatly increased, and hence the advice to always cut back to not only clean but also to strong and thick metal before attempting to weld.
The correct preparation of the metal which is to be welded is vital. All traces of rust, of paint, oil, grease and any other contaminant must be cleaned from the surface to avoid poor adhesion and spiting. Any impurities which find their way into the welded joint will substantially 11 Taken it.
When a joint is being welded, both surfaces should be thoroughly cleaned; if paint or any other contaminant is present on the underside of the panel then it will mix with the molten weld/steel and weaken the joint. Recently, special paints have become available which can be used on surfaces which are to be spot or MiG welded. The use of these products — such as 'Autoline' weldable zinc primer, will ensure that the welded joint does not — as is normal — become the first part of the repair to rust through again. The metal panels must then be clamped in some way so firmly that the heat of the welding process does not distort either of them and allow them to move apart. Small sections may be clamped using mole grips, although longer runs are usually affixed using self-tapping screws or alternatively pop rivets at regular intervals. the joint. Recently, special paints have become available which can be used on surfaces which are to be spot or MiG welded. The use of these products — such as 'Autoline' weldable zinc primer, will ensure that the welded joint does not — as is normal — become the first part of the repair to rust through again. The metal panels must then be clamped in some way so firmly that the heat of the welding process does not distort either of them and allow them to move apart. Small sections may be clamped using mole grips, although longer runs are usually affixed using self-tapping screws or alternatively pop rivets at regular intervals.
