TIG filler rod recommendation for oil pan?

[pvfjr]

I bought a 2001 S40 project car that came from an auction at some point. It was supposed to "run and drive", but had a large hole in the oil pan, so the previous owner never did anything with the car.

I've got a TIG welder at home that I haven't used yet. I've never gotten around to buying all the necessary consumables for it. I figure I ought to practice on some steel first, then some scrap aluminum. I'd like to make sure I pick some filler rod that will work for the oil pan while I'm at it though. Anyone have any recommendations? Does anyone have any insight as to what alloy is used on the oil pan?