NuMetal?

[harrisonm]

Maybe someone else can chime in and let me know.

if there is a dime size rust hole, and all the rust is cleaned out, can I use a mig welder to just slowly close it up, or do I need to put a piece of sheet metal?

I have been doing major rust repair as a hobby for about 30 years. I will say that a dime sized hole needs a dime sized patch piece. If you are really careful, control the heat and use a copper backing plate, you COULD successfully do it, but I would use a patch.

 

[wheelsport]

I used the product that turns black when applyed to rust. I cleaned out the rust pits with a wire wheel until I saw shiny metal and then soaked it with lot and lots of rust stop. I let the surface dry for a couple days and filled the pitting with filler. That was 5 years ago. No signs of bubbling.

 

[Swinger 340]

Usually rust forms inside, out. The reason rust forms at the top of vehicles along the drip rails and windows is it's difficult to seal behind those areas. Keeping the cars dry, stored inside and the side windows open a little will help in preventing condensation forming in those areas. The patch panels are the way to go if you can get behind them to seal them off from moisture getting to the rear of the patch panel. I have used a product called ospho, that is a liquid that stops rust. Using a patch over the product may burn it off, so I would applied it on the back side and use a good filler if not to large a patch and you can't get behind it to seal it .

 

[barbee6043]

There is a thread where undercoating is discussed. I have always believed floor rust starts on the inside uder the carpet due to leaks at windshield cowl, etc and having the carpet over the floor. Have a car sit outside and the critters get in it and tear up the seat insulation, and pee, and see what is left after a couple decades outside!!
I like undercoated floors my self.

I have always felt the trunk extensions rust from inside. Same with bottom of doors.

 

[ESP47]

There is a thread where undercoating is discussed. I have always believed floor rust starts on the inside uder the carpet due to leaks at windshield cowl, etc and having the carpet over the floor. Have a car sit outside and the critters get in it and tear up the seat insulation, and pee, and see what is left after a couple decades outside!!
I like undercoated floors my self.

I have always felt the trunk extensions rust from inside. Same with bottom of doors.

Yep and throw leaky heater cores onto the list there. It's why the front floors are almost always rusted while the rears are usually in good shape. Original rubber mats being used instead of carpet also was a big proponent in holding moisture in.

Leaves and other crud slip down in between the quarter and trunk extensions and then they hold water and rust from the inside out. It's very difficult to clean far enough down in there to get everything out. I provisioned a small hose to my vacuum attachment to slip down in there to get the stuff out on my non rusty side. It took a while but it finally worked. The rusty side had all sorts of presents down in there once I got the quarter off. Including a New kids on the block keychain lol