Spot welding sheet metal deformation help

[blitz97]

I continue to have issues with spot welding cold rolled sheet metal(16ga up to 22ga) and visible deformation of the area once powder coated.

Does anyone have any tips for reducing the amount of deformation of the sheet metal around this area. Weld tips, voltages, etc?

A secondary sanding operation has been added which helps but not all the time.

Am I expecting too much!

 

[MikeHalloran]

Cars have thousands of spot welds. You don't notice them because they're on flanges that are tucked out of sight, or concealed with filler. I don't think it's possible to conceal a good spot weld with just paint.

You can screw around with electrode shapes and pressure settings, but basically, if the electrode didn't leave a mark of some kind, you probably don't have a weld.



Mike Halloran
Pembroke Pines, FL, USA

 

[volpe2]

I have had good results using bondo putty to cover spot welds. Also, a powder coat with a rough finish will hide it better than a smooth one.

Mike is right about the spot weld settings. There is nothing worse than having a welded assembly fall apart in your hands and trying to identify defective parts in wip and inventory.

Matt Evans
Moorestown, NJ

 

[griffengm]

Awidrig,
We use your metal gauges a lot and there are a couple things you might try.
Use a large dia swivel on the lower tip with a small tip upstairs. Keep the surface you want to keep mark-free on the bottom and less critical on top.
Really look hard at your setups of time, pressure and voltage. Sparks flying on video of autobody welders may look impressive but in reality there should be no molten metal flying around.
Probably should go without saying but make certain your operators/setup people are actually setting parameters and not just entering their lotto numbers. Too many operators "adjust" parameters without understanding the relationships.
Hope this helps some.

Griffy

 

[blitz97]

Thanks everyone for your insight. I will take these suggestions and see what I can come up with.
Andy