Irontite Electro Magnet Kit

Why Use an Electro Magnet to find cracks?

It’s called, “Magnetic particle inspection”, and is most often used to inspect cast iron cylinder heads for surface cracks in and around the combustion chambers. It can also be used for inspecting crankshafts, camshafts, and connecting rods. Even more possible uses, are to check gears, shafts, axles, and steering and suspension components for cracks, too. I’ve even seen it used on Heavy Duty Brake Rotors.

A magnetic field is created by the electromagnet. And then tiny iron oxide particles are sprayed or brushed on the part to reveal any cracks. If there are any cracks in the surface of the part, they will disrupt the magnetic field and act like a pole to attract the iron particles.

The iron particles used to detect cracks are easily magnetized but don’t stay that way for long (so they don’t stick together or to the metal being tested and can be reused). Particles are dyed yellow, white, red, gray, black or with a fluorescent color to improve their visibility against the metal background. With the fluorescent particles, ultraviolet black light is required to make the particles stand out.

A/C Magnets vs DC Magnets

When checking for cracks, the stronger the magnetic field the more easily it will reveal cracks. For this reason, more powerful electromagnets or magnetic coils may be better than less expensive permanent magnets. The magnetic field may be generated with alternating current (AC) or direct current (DC).

AC units are usually not as strong (only 10 pounds typically) in creating a magnetic field. In many cases, with detecting the workpiece, there is -0- (zero) magnetism remaining in the tested component once the unit is turned off.

Typically when checking a rod, crankshaft, valves, etc., remaining magnetism is not wanted as it will attract metal to the checked part after checking, so an AC unit is required.

Do I want Adjustable Legs?

Adjustable legs are great if you need to go around curves, however, they allow for a weaker magnetic charge to the casting.

The Irontite Electro Magnet

The Irontite DC magnet is made in the U.S.A. Irontite factory. We have been making it since we started back in the early ’50s. Designed with the machine shop user in mind. It is intended to be used in detecting cracks in cylinder heads & blocks. Once located, casting repairs are either done by our cold casting repair method of removing the cracked fatigued metal and replacing it with fresh new metal or for the few remaining hot welders in this industry.

All of our magnets are run through a 90-pound drop test, with fixed solid legs (non-adjustable) so they create a much greater and stronger magnetic field to the workpiece being tested. This allows the magnetic powder to fill the void of the cracked area of concern making it visible.

Any remaining magnetism created with a DC unit will generally dissipate within 24 hours.

[Power Tip] To speed up the dissipation process, a hammer blow to the end or side of the casting will dissipate most of the remaining magnetism left behind immediately.

Feel free to download and review the Irontite Electro Magnet Manual.

To Clean or Not to Clean

If you intend to media Blast first, this will peen and possibly close a crack that is needing to be detected. The stronger the Magnet unit, the easier it is to detect cracks. So using a DC Magnet over an A/C would certainly help in cases where you have a media blasted casting.

You can purchase the Irontite Electro Magnet Crack Detection kit direct from the manufacturer.