Destructive weld tests are necessary and not included

May 18, 2015
Destructive weld tests help to ensure proper weld set up, but this crucial step is a non-included item, so how shops need to be compensated is up to them.

I was recently asked to conduct a post-repair inspection on a vehicle that had been repaired after an accident. To be blunt, I was appalled at the quality of repairs made to this Nissan vehicle. There were still buckles in the trunk floor. There were things the shop charged for but didn’t do. And most specifically, I was appalled at the incorrect number, type and quality of welds used to attach the read body panel.

I was looking at the “repaired” car before it had been disassembled for the inspection. My good friend Larry Montanez with P&L Consultants and ABRN Technical Editor, inspected the same vehicle after it was disassembled. He was able to pop the welds loose simply by prying on them with a screwdriver. That’s just scary.

As I said in a previous column (Understand your liability, April 2015), we have both a legal and moral obligation to put vehicles back together in a safe and proper way. The welds I saw on that Nissan were very concerning to me. It got me wondering just how many shops know how to perform welds according to the automakers’ specifications for each vehicle.

You need to perform the correct type of weld. You need to use the correct type of welder, with the correct settings, the correct wire, the correct gas mixture. In some cases, components that were welded on at the factory are not to be welded on during repairs; in some cases, manufacturers don’t want you to weld on the replacement but to use rivet bonding, using specific rivets and adhesive instead.

So it’s important to research what the automakers say to do when it comes to welding. One thing you will find that many of them call for is destructive weld testing prior to welding on the vehicle. This ensures you have the welder set up properly.

Check out the body repair manual for the 2011 Ford Mustang, for example ( Before the welding process begins on the vehicle, Ford calls for a welding a sample.

“Place the welded sample in a vise and carry out destructive weld tests by peeling the scrap metal apart using large lock-type pliers,” the Ford document states. “Measure the weld nugget to determine that the nugget meets Ford weld nugget requirements. If the weld nugget does not meet required size, adjust welder settings until the correct weld nugget size is achieved. When the correct weld nugget size is achieved, the service part can be weld-bonded.”

Or check out I-CAR’s “Uniform Procedures for Collision Repair” on squeeze-type resistance spot welding ( The first step it calls for is verifying the automaker recommends that type of welding for use at the repair location.

And again, prior to welding on the vehicle, it calls for making “sample test welds on scrap pieces of the same type and thickness as the parts to be welded. Visually inspect and destructively test the sample welds to verify the welder settings and the weld quality,” the I-CAR document states.

ALLDATA’s welding precautions insist that, “A test weld should always be carried out on a test sample.”

Toyota’s collision repair bulletin No. 181 on welding specifications ( states that, “Weld strength must be validated by tuning the welder and performing destructive testing. Tuning the welder and destructive tests must be performed on metal of the same thickness and composition as that of the component being replaced.”

If your technicians are doing the required destructive weld tests – and I know many who do – you should also understand this crucial step is also a non-included operation. I’m not suggesting that anyone should or should not charge for “set-up and perform destructive weld testing,” and you obviously should never charge for something you don’t do. I’m just saying you should be doing this procedure, it’s an non-included operation, and it's up to you to determine how you need to be compensated for it.

I salute the automakers that have strict welding test requirements for certification, and I-CAR for its welding qualification program. When I owned my shops, I sent my technicians to the Lincoln Electric Motorsports welding course ( My techs often said it was some of the best training – both theory and hands on – they’d had.

I don’t want to keep seeing bad welding like I did on that Nissan. What we do can impact someone’s life in the event of another accident.

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About the Author

Mike Anderson

Mike Anderson, a former shop owner, operates, a training and consulting firm. He's also a facilitator for DuPont Performance Services' Business Council 20-groups.

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