I bought a 50" deck over the weekend for my 318. I got it at a good price because of the rust and condition. Of course we all know that the areas of rust is the "basin" section where everyone had those covers and wet grass hung around that area forever.
Anyway I tore the deck down and used an outdoor torch (you know the huge flamethrower torch) to burn off all the paint. It removes pretty much all the plastic coat paint and any organic debris. I see now the center area is moderate to heavily pitted. However, it's still solid, I hit it with a hammer and it holds up pretty well. There are no corrosion holes in the deck. My question is what can I do before pre and paint to "reinforce" the deck. I was thinking maybe to weld angle iron underneath along the existing ribbing to provide reinforcement. I did buy reinforcement rings that go into the spindle holes. The rings are 3/16" thick and I used them in my 46" deck with great success.
The other thing I was thinking was using Bondo or some fiberglass filler material, however I don't think this will provide structural reinforcement.