Modern Magnetic Clamps for Welding

One interesting application of the well-known principles of magnetism is in the creation of magnetic clamps to use in place of mechanical ones (C-clamps, vises, and the like). These are most useful in two ways – they can hold pieces of steel in place where it is not possible to attach more standard clamps, such as when welding a fabricated patch insert into an automobile exterior where a corroded area was excised; and they are very quick to move from place to another, rather than the slow process of screwing and unscrewing clamps. As a more marginal benefit, they do not have the potential to cause surface damage that mechanical clamps have in the absence of shims.

The “pull” of a magnet is usually listed in its product description, and is rated in pounds. You should have a safety margin a bit over the pull that would theoretically suffice, in case you accidentally push on one of the pieces of metal
Magnetic clamps may resemble plain metal bars or they may be arrow shapes that allow you to align straight edges easily. The smallest are best for light clamping jobs where little pressure will be applied – such as the aforementioned grafting of a clean new piece of sheet metal into a car’s rust-damaged skin. There are also much more powerful magnetic welding clamps, including many that are designed for holding pieces set at right angles in position, miter clamps, and so on.

Arrowhead-shaped clamps are more useful because the two projecting flanges of the “arrowhead’s” base allow you to line up a straight-edged piece of metal precisely in some circumstances. They can also be used to hold base metal pieces at precise 45˚ or 90˚ angles, depending on how they are arranged. The two sides of the “arrowhead” form a 90˚ angle, while the angle between the base of the “arrowhead” and one of its sides is 45˚ - a clever application of the dimensions of a relatively simple shape to a multifunctional magnetic clamp.

One problem that is unique to magnetic clamps – somewhat offsetting their many other excellent qualities, such as ease and speed of use – is due to the fact that they are magnetic. Steel dust from grinding, spatter from welding, metal shavings, and so on will all be attracted to the surface of the magnetic clamp. This accumulation, if it is not removed, can eventually affect the performance of the clamp by distorting its surfaces out of true, as they begin to bulge with built-up metal debris.

Switchable magnetic clamps are the answer to this problem – the magnetism of these clamps can be switched on and off. Thus, the magnetism can be switched on when the clamp is being used, then, once the task is completed, the user can switch the magnetism off and the debris that accumulated will simply drop off the surface. These clamps can be identified by the large on/off switch, much like an ordinary light switch, on their side.

Generally speaking, when you are outfitting your welding workshop, you should consider acquiring both mechanical and magnetic clamps, so that you can use the magnetic clamps for fast, maneuverable clamping and their mechanical kin for stronger fastening on welds that are likely to take a long time to complete.