Fixing Metal in Place while Welding

While pliers and tongs are useful for quick manipulation of metal – moving it from place to place, holding it together for a few minutes, and so on – they still need one of your hands to operate them. Very frequently, you will need both hands for welding and will be unable to hold a pair of pliers at the same time. This is the moment when various kinds of clamps come into their own, to hold the different pieces of metal firmly and steadily together so that they will not shift or fall while you are attempting to weld them.

The advance of technology has opened several new clamping options with the creation of various magnetic clamps also. These obviously cannot be used on aluminum, but there are situations in steel welding where magnets may be better than mechanical clamps – such as when welding a carefully-shaped sheet metal patch into a hole in a car body panel which is still attached to the car, and it is impossible to pinch the metal in place from both sides.

A heavyweight vise attached to the worktable is one of the strongest types of clamp available to the home or small-shop welder, and can be used for a huge range of different jobs. A vise is useful because of its strength and the fact that the weight of the whole table helps to keep the metal solidly in place. This is also its disadvantage – it can only hold objects in one position, usually with a vertical pinch. The jaws should open to at least 6”, and preferably 8”.

The vise is used not only for welding, but for holding pieces of metal while they are being prepared for welding in various ways. Metal can be sanded or ground while held immobile in a vise, or cut, and can also be bent – possibly with the help of some heat from an oxyacetylene torch to soften the metal temporarily at the point of bending.

For somewhat less firm but far more adaptable clamping, the familiar C-clamps and the less widely known F-clamps – also called bar clamps and speed clamps – are excellent choices, and you should be sure to equip your work area with several sizes. C-clamps are the most frequently used and can hold objects from a few mils to a few inches thick together. The closer the objects’ total thickness is to the span of the clamp, the less firm the clamping will be, since leverage between the screw and the other arm of the frame is lessened. The effect of the screw’s tip on the surface can be lessened with an aluminum shim.

F-clamps are similar to C-clamps but feature a long bar between the arm holding the screw and the other arm. They are used for much larger clamping jobs, and although you are unlikely to use them for many welding projects, it is useful to know that they are available in case very wide clamping becomes necessary.

Magnetic clamps, the latest invention, are also very useful in many situations – they are the topic of the next article, which covers them in detail. Mechanical clamps are very useful because of their reliability, their familiarity, and the fact that they can clamp any type of metal together – including non-magnetic metals such as aluminum.