Sunday, 31 July 2005 17:00

I-CAR welding test challenges even experienced techs

Written by Toby Chess
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Last year, I was hired by Holmes Body Shop, a large Los Angeles-area chain, to set up training and quality control procedures for the company. About a week into the job, I inspected a vehicle that had new front end structural parts installed with plug welds. Though I couldn't determine their exact structural integrity, the plug welds visibly ranged from good to poor. While the technician prepared to redo the welds at my suggestion, I observed his welding techniques while performing some practice plug welds. 

After suggesting that he change his gun angle and increase the "stick out," I discussed the situation with Vice President of Oper-ations Steve Morris and Center Manager Wade Sill. Both men concurred that the welds needed to be redone, which the technician subsequently successfully completed. This gave me the opportunity to recommend that all the technicians in the company take the I-CAR steel welding qualification test

I-CAR steel welding test

The test consists of performing six welds - a butt weld with backer, a fillet weld, and a plug weld in the vertical position; the same three welds are then done in an overhead position. The completed welds are sent to a testing company where they first must pass the visual test. If the welds pass, then they are destructively tested. If all six welds pass both tests, the technician is given a certificate of completion, which is good for 5 years. If any of the welds fail, the technician can retake the test within six months and redo only the welds that failed.

Based on my recommendation, Morris sent thirty technicians to take the test. As an added incentive, they were offered a new automatic darkening welding helmet if they passed the test on the first try. Twelve of the 30 techs did pass the first time Fourteen techs failed only one weld, three failed two welds and only one - who is no longer with the company - failed three welds.

To date, 15 of the remaining 17 technicians have retaken the test and passed. The other two have been practicing and are scheduled to retake the exam. Ironically, the tech whose poor welds prompted the company to introduce the testing policy passed all his welds on the first try. He also tutored one of his helpers, who also passed on the first try. Moreover, he arranged with me to purchase two new Millermatic 135 welders for him and his helper.

The company has since installed a welding purchase program whereby any tech who has passed the I-CAR exam is eligible for a company loan to purchase his own Millermatic 135 machine. The money is paid back with a payroll deduction.

Morris and Wade are pleased with results of the test and company policy now requires that all employees take and pass the I-CAR welding qualification test as part of their employment requirements.

Marcos Auto Body

Another validation of the welding qualification test took place with the technicians employed at Marcos Auto Body, which has four LA-area locations. When I approached owner Marco Maimone, he set up a testing date with me for seven technicians.

Maimone even signed himself up though he had not welded on a car since the turn of the century - and not the 20th but the 19th century. It took him nearly a full day of practice, but he managed to get through the test. He told me that everyone was extremely nervous, but to a man, they felt that their welding skills had greatly improved due to the coaching in the pretest. All passed the test that was given that day.

One thing I noticed as I observed the techs was improper gun angle and a misunderstanding of the purpose of the shielding gas. Let's take a quick look at the MIG welding process.

A primer on MIG welding

First, many managers, estimators, and even shop owners have no clue about MIG welding, yet it is the method of choice for welding on today's cars. The technical name for MIG (metal inert gas) welding in GMAW, which stands for Gas Metal Arc Welding.

Figure 3 represents a typical MIG welding gun and process. The things that are of interest to non-technical people would be the shielding gas, wire size, gun angle and stick out.

Stick out is distance from the end of the contact tip to the welding surface. The recommended length ranges from ΒΌ inch to 3/8ths of an inch. Shorter stick out lengths cause the electrode wire to fuse to the tip, which in turn causes the wire to stop feeding the weld. Another problem with a short stick out is that the technician cannot see the weld properly as it can be hidden by the nozzle.

The proper wire size for most collision applications is .023 wire especially with 110 volt welders. It is possible to use .030 wire, but it works better with heavier gauge steel which is the wire of choice with 220 volt machines. The wire should not be flux coated.

The shielding gas used is a mixture of 75% argon and 25% carbon dioxide. The welding gas is not needed for the welding process, but is necessary to keep nitrogen and oxygen out of the weld site. Why you ask? Nitrogen and oxygen can cause fusion defects and porosity. Improper gun angle (70 degrees or less to the welding surface) will allow the gas to blow away from the weld and oxygen and nitrogen can contact the weld during the welding process.

The proper gun angle is 10 degrees from perpendicular to the welding surface (Diagram 3).

Sample welds

Recently, prior to the pretest part of the I-CAR welding program, I had eight technicians perform two plug welds and then asked them to select their best one. Look at the sample of one of the welds.

How would the weld in Figure 1 be judged? Well, this weld would fail the visual test right away because it is too small in diameter.

This weld in Figure 2 also failed the destructive test.

The plug weld in Figure 3, when pulled apart, left a hole in the top coupon, which indicates that there was no weld penetration to the top coupon. To pass the destructive test, the plug weld needs to remove metal from the bottom piece of sheet metal (minimum tear out is 5 mm hole). Seven of the eight techs would have failed the I-CAR qualification test, if their initial plug welds were submitted. After practicing for over four hours, all eight techs submitted eight plug welds for testing that I felt would pass both visual and destructive tests.

The Figure 4 weld failed the destructive test because there was also no penetration to the bottom coupon even though the weld passed the visual inspection for size and filled the 8mm hole completely.

Welding demo for AAA

A number of insurance companies have expressed a desire to learn more about the I-CAR welding qualification test. Recently, I put on a welding demonstration for the Automobile Club of Southern California.

Two of the IRP adjusters put on welding jackets, gloves and a welding helmet to try their hand at welding. After demonstrating proper gun angle along with a mini lecture, within 20 minutes, they were welding. Both managers enjoyed the experience and gained new insight into proper welding and an appreciation for skills of repair technicians.

Only I-CAR training accepted

Another factor that should be considered is that General Motors, Ford, Toyota, Lexus, Volvo, Chrysler, and Jaguar only recognize I-CAR's qualification test for their collision certification programs. You can find the OEM requirements at www.i-car.com (center of the home page).

The following shop owners have or will have all their technicians pass the I-CAR welding qualification test: Randy Stabler of Pride Collision Centers, Steve Vetell of Pacific Collision Centers, Eric Bickett of Fix Col-lision Centers, Tom Williamson of Marina Auto Body, Norm Larson and Jeremy Beltzer of Auto Body Masters, Yunan Safar of Y&S Autobody, Greg Gunter of Greg's Auto-body, Bruce Mackie of Bodycraft Collision Centers, Ole Vandborg of Scandinavian Coach-craft, Steve Seidner of Seidner's Collision Cen-ters, Doug Meves of Craftsmen Auto Body, Sam Miller of Motor City Auto Center, Jeaneene Campbell of Central Body Works, Craig Cameron of Scott Robinson Honda, and Frank Schiro of Schiro's Collision Centers.

If you have any questions or your company also has achieved 100% passage of the I-CAR welding qualification test, e-mail me at tcspeedster@yahoo.com. Please include I-CAR Welding as the subject.

 

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