Body panel adhesive

I have to do a small repair on my 2009 Honda Ridgeline. It is rusted between the gas filler door and the wheel lip, right where they all seem to go. I do have a mig welder but am a little concerned with welding that close to the gas filler. Any suggestions regarding a good body panel adhesive? The whole patch is probably 6 inches deep by 9 inches wide, so I don't need much. I would also like to avoid having to buy an expensive applicator gun, as this is a one off repair.