Senior MTF Member
Join Date: Oct 2009
Location: Lowell area, MA
Re: Broken Deck Hanger - Best Fix?
I just had to weld a patch plate over a rust hole in my mower deck. The steel was around 0.090-0.100" thick. I have a 110V 140A MIG welder, using 100% CO2 shielding gas.
It seemed to work fairly well. I tried to remove the rust with a wire wheel, and flap disk. I tried to "seal" the outside of the deck, welding the rusted opening to the new patch plate, to keep moisture out of that gap. In some areas, I cut the rusted steel back a bit, to kind of clean it up the ragged opening. Welding along that edge was OK. But in other areas, I welded right at the remaining edges of the rust hole. That didn't work as well. At the edge of the hole, the steel was so thin that I kept burning right through it, even with the welder turned down all the way.
If you're welding a little ways from the edge of the hole, it should be easier to avoid blowing through. I'm assuming that it rusted through, and is really thin around that opening. If it just broke off, then maybe it's thicker there, making this easier.
You can also put a backing material on the other side of where you're welding, to avoid melting through the deck. Use a different material, not steel, so that you won't weld that backing material to the deck. A piece of aluminum, copper, etc, would work. It helps draw excess heat away from the area, and also just provides a physical block to blowing a hole through the steel.