Rust Hole Boundaries?

[AARGeister]

Hey,

When one welds in a patch panel to replace a rusty panel, how much further from the actual hole should the piece go?  What I mean is how much further from the actual rust hole is the steel useable?  I am thinking around 1 inch.

[OUTLAW]

when I was doing my body work I ground the metal down to where it was solid then extended my patches 1/2 an inch to 3/4 of an inch where possible

[ShelbyDogg]

Where the rust stops is where the metal is solid again. I dont usually leave an overhang. I cut the piece to fit the hole then butt it in.

[Wang]

1 inch,,, good rule of thumb.

Butt welding is the ultimate repair,, no overlap.,, no place for moisture to hide.

[js23nob]

Iam doing a 69 barracuda here in OZ for a customer, on the outside it looked like a small pin hole of rust but when I cut the panel off it was five inches above the pin hole there was still rust in the panel.
When doing rust when you cut the panel off ,turn it upside down if there is still rust there keep cutting