Steel Spot And Plug Weld Nugget Size: BMW/Mini - UPDATE

Did you know that some OEMs specify nugget size for spot and plug welds? This information is typically found within vehicle-specific repair procedures or can be found under general welding guidelines.Let’s see what BMW/Mini has to say.

BMW/Mini welding requirements can typically be found in the document Welding Steel Components. A search for the document title or a search for "welding" brings up this document on the service site.

Spot Welding

BMW does not indicate a specific spot weld nugget size in their collision repair information.

The Welding Steel Components document states that squeeze-type resistance spot welding (STRSW) and GMA welding are both acceptable for repairs and clarifies with the following:

• "Take the number and position of welding spots and MAG weld seams from the separated part. Replace areas inaccessible to spot-welding tongs with MAG plug welds at the same distance."

This means that when performing repairs, welds should be replaced in the same location and in the same quantity that was used from the factory.

BMW Spot Welding Requirement/Recommendation

Per our contact at BMW: "In an instance where welding is not specified. The rule it to first spot weld if possible following BMW guidelines, if not possible MAG welding would then be the choice."

Plug Welding

BMW does not indicate a specific plug weld nugget size in their collision repair information.

The Welding Steel Components document goes on to state:

• "During MAG welding, the weld gap must be kept as small as possible. The larger the weld gap, the lower will be the strength of the joint.
• In order to keep the electron flow short during MAG welding on the body, you must if possible, attach the ground terminal directly to the component to be welded.
• Minimum distance between welding spots 25 mm.
• Diameter of bores for plug welding is 8 mm."

The general welding information found in the Welding Steel Components document does not replace vehicle-specific OEM procedures. If a different attachment method is identified in an OEM procedure, that is the attachment method that must be used.

Where the spot weld and plug weld nugget size was not identified, refer to the Steel Spot And Plug Weld Nugget Size: UPDATE article. This article provides general guidelines.

Following OEM welding requirements, including what nugget size is required, will help ensure a complete, safe, and quality repair.

For additional BMW/Mini information, check out the following pages:
BMW OEM Information
Mini OEM Information

Additional I-CAR Collision Repair News you may find helpful:

• Back-To-Basics: Destructive Weld Testing
• Collision Information Website Access: BMW/Mini
• Dressing Steel GMA Welds: UPDATE
• Steel Spot And Plug Weld Nugget Size: UPDATE
• Step-By-Step: Accessing BMW/Mini Repair Information
• Weld-Through Primer Guidelines: BMW/Mini
• Welding And MIG Brazing Hotspot

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Article validated in 2022