[JeffTheGreat]

I have a black iron garden trellis that has one corner badly rusting and crumbling apart. Can you think of a good way to repair it? Would auto body filler work? The rest of the trellis is still quite solid.

[JeffTheGreat]

The trellis frame is made of hollow square 2" by 2" iron. I am thinking of first placing a piece of 2 by 2 lumber inside that corner to give it some strength. Then I want to some how smooth-off / fill-in that rusted off metal and refinish /repaint. Unfortunately, all the rust-proofing products that I have used in the past did not work. I wish I could some how stop the metal from rusting out more.

[Poppy]

Jeff,
Ideally you would cut out the rust and have a new piece welded in place.

I suppose that you could make a temporary patch by filling it with a spray can of expandable foam, and covering it with fiberglass and resin. I don't know how many years you'll get out of it that way though.

[grog11]

Looks like the tube ends are open and let the weather inside. I would take an electric grinder/wire wheel to remove the existing rust, then cut the tube end off enough to eliminate the eaten away part.( Hacksaw) Cut off the other tube ends to match.
Apply some naval jelly applications on the bare metal to convert existing rust. Then paint to match. They make 2" plastic trailer hitch inserts that should slide inside the tube to make a weather tight seal.