Using Magnetic Ground and Holding Clamps When Welding

This article is aimed at providing answers to the question of whether you should use magnetic welding clamps and grounds by addressing the pros and cons of their use, concerns about durability, cost of the equipment, and some potential alternatives. 

Pro’s and Con’s of Magnetic Welding Clamps and Grounds

There are numerous advantages to using magnetic welding clamps and grounds, most of them point back to the reason why magnetic welding clamps and grounds were invented in the first place: for added convenience.

Some of the pros of using magnetic clamps and grounds include:

  • Pro: Using magnetic clamps and grounds instantly increases welding productivity. Instead of twisting traditional screw-type clamps in and out, magnetic clamps and grounds allow the user to simply stick a magnet onto the surface of the workpiece and start welding. 
  • Pro: Welding towards the middle of large structural, square, rectangular, or circular steel pipe becomes much more convenient. In the case of welding on an oversized work piece such as pipe, a magnetic welding ground makes grounding your weld – in some instances – possible.
  • Pro: In applications where you are welding on a workpiece which has only a portion of the base metal exposed (such as in an automotive repair shop where a body panel is taken down to bare metal only in a certain area) grounding becomes easier or even possible. 
  • Pro: Magnetic clamps are worth their weight in gold when welding sheets of metal which need to be constrained in a perpendicular orientation without any elaborate jigs or fixtures. A magnetic clamp can simply stick to the metal in the corner of the joint and hold the workpiece securely. 
  • Pro: Using magnetics can decrease cost in setting up elaborate fixtures such as in ship building where “dogs and wedges” are used for sheet metal fit-ups. Costs can be decreased in labor by decreasing a two-man job to a one-man job, simply by using an optimized magnetic work holding solution. 

Given the many great advantages of using magnetic clamps and grounds, there are some downsides of using them.

Some of these disadvantages include:

  • Con: Magnetic clamps and grounds will only work on ferrous materials. This means that for applications where you are trying to weld aluminum or non-ferrous stainless-steel materials, you will need to find an alternative to using magnets. 
  • Con: Special care must be used when using magnetic clamps and grounds. Unlike other welding equipment which can be used heavily on a busy jobsite, magnetic clamps and grounds cannot be thrown into a box, dropped on the ground or accidentally struck with another piece of equipment. 
  • Con: If the magnetic clamp or ground becomes demagnetized in part or in full, there is a good chance that the clamp or ground may fall off your work piece while you are performing your welding job. This can be costly, dangerous, and annoying. 
  • Con: In the case where the magnetic clamp or ground is close in proximity to your weld bead, there is a chance the magnet can interfere with the weld puddle and cause arc blow which is very difficult to control and can cause diminished weld quality. 
  • Con: In shops where there is cutting and grinding (most weld shops), there is a high likelihood that your magnetic clamp or ground can accumulate metal filings on the magnet surface and cause extra cleaning of your magnets prior to using them. 

Durability Concerns

The durability of welding magnets used for clamps and grounds is a common concern for welders. This concern about durability is actually backed by science.

Two things that welders do most, preheating materials and hammering the workpiece to remove slag from the weld bead.

The science behind the diminishing magnetic field (demagnetization) is based on the strength of the magnetic dipoles of the material.

When either high heat or a high amount of vibration traveling through a magnetic field, the magnetic dipoles are disrupted and change their orientation to become less magnetic.

When a magnet is heated to a temperature called the Curie point (different temperatures based on the base material) the magnet’s strength will be decreased.

Therefore, in order to maintain a magnet’s strength, you must treat it with at least a minimal amount of care so that the magnetism of the tool is maintained. 

One important area to be aware of is the amperage rating of your magnetic welding ground.

Using an incorrectly rated magnetic welding ground can cause your magnetic welding ground to demagnetize and/or cause a dangerous arcing situation.

Use the properly rated magnetic welding ground for your application. There are different amperage varieties on the market including magnetic welding grounds rated anywhere between 300 and 600 amps. 

Cost of Magnetic Welding Clamps and Grounds

High-end magnetic welding clamps and grounds have higher quality, magnetism strength, and long-lasting durability. Some brands that fall under this higher-end category are Magswitch, Industrial Magnetics, both of which cost more than other brands.

In the case of magnetic welding clamps and grounds, you really get what you pay for since there are varying levels of quality in this category of product.

If you need a larger, stronger magnet, you should expect to pay more for it than a smaller weaker one. 

On the other end of the spectrum there are the super economical versions of magnetic welding clamps and grounds. Case in point is a product listed on Harbor Freight’s website, a 4-pack of welding clamps for the low price of $5.99.

The only reason that I would recommend something this economical (and most likely cheaply made) is if one of my friends was looking for a “throw away” set of magnetic welding claps that they would only be used for one project then not need them anymore.

Magnets at this price point are made from lesser quality materials and therefore have lesser durability over time.

The last thing you would want to happen while you are performing a weld is for either your clamp or ground to come loose from your workpiece – not only is this dangerous, but very frustrating.

Alternatives to Magnetic Clamps and Grounds

When magnetic welding clamps and grounds are simply not an option, whether there are issues with the workpiece ferrous qualities, workpiece sensitivity to magnetic fields, or an absolute need for ultra-high strength clamping, there are always alternatives.

After all, steel workers, or welding professionals in general, have been constructing countless welded structures for over one hundred years now.

The typical solution for abnormal clamping and grounding situations is to weld either a dog or a stud onto your workpiece.

In the case of a necessary ultra-high strength clamp, a dog might be welded onto a plate of material, and in conjunction with a wedge, a plate can be moved and clamped into position for welding.

Shipyards use this clamping methodology all the time since they regularly weld together large plates of material while holding tight tolerances.

On a smaller scale, in instances where a welding ground is needed, and magnets cannot be used, a bolt or a stud can be welded (or spot welded) to the workpiece for the sole purpose of grounding the weld, then it can be cut off and ground smooth after the weld is complete.

This methodology can be used in applications where the workpiece is non-ferrous such as with aluminum and stainless steel.

Conclusion

Expert welders agree that 99 percent of hobbyist welding applications don’t require magnetic welding clamps or grounds – the scope of hobbyist applications are simply limited enough to only require the use of conventional clamping and grounding methods.

If you have either determined that you need magnetic equipment for your welding application or if you need assistance, deciding on this type of equipment it is strongly recommended to visit your local welding store.

Your local welding store typically has someone there who is very knowledgeable in welding equipment and will be happy t assist you. 

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