where to buy sheet metal

[toddscharger]

Where would  I get plain unformed sheet metal to create patches for under the battery tray in the engine bay of a Charger, or for replacing the sheet metal that  is under the driver's side door jam.
Would the sheet metal they sell at Home Depot or Lowes be of the proper compostion or is there special automotive body grade sheet metal out there?

How would you measure the gauge of sheet metal to know what gauge you needed to buy?

Thanks, Todd

[Upholstery guy]

I don't know the answers to your questions but, here's some info about sheet metal.

I don't know the gauge of classic cars but here's a chart of gauges, the left blue column shows the gauge and the center blue section shows the thickness: http://www.engineersedge.com/gauge.htm