Suggestions on this repair.

[bossbob]

What is the best way to repair this spot. Weld it up/Grind it down, it's almost too small for a patch, maybe the size of a dime.



Thanks again,

[peter]

Grind it out and make an new peace of sheet for it and weld it in.
It's not that hole but all the colored parts are bad too.

[bossbob]

What gauge sheet should be used? Unfortunately, a majority of the car id discolored like that. Can't cut it all out..........

[C.Costine]

I cut a lot of rust out of mine and replaced it with 20 gauge. I recommend butt welding as opposed to lapping over. You can get little clamps at Harbor freight specially made for holding pieces for welding. As Peter says the area that is thin is much bigger than a dime. You can cut out a rectangle with a cut-off wheel. Then cut a rectangle of 20 gauge to fit. I used my Dremel with cut-off wheel for small stuff like that. As you are cutting it to a rectangle you will find out how far the too thin area actually goes.

[redroadster]

How great of a welder are you .
Cause if you can weld new sheet steel with that rusty pitted through metal solidly, it needs to be shared on youtube
My suggestion would be to use muratic acid on the rust showing instead of grinding/sanding ,clean with brake clean- water- brakeclean
Then with fiber putty and a 8th " screen behind the hole fiber putty or braze it in
The look of the quarter at that spot looks like its mostly gone or the acid will tell.
Brush on rust metal primer

[pebbles]

Then with fiber putty and a 8th " screen behind the hole fiber putty or braze it in

I prefer magazine paper.

[Gregs672000]

Agreed with all methods, but it depends on what YOU can do, or are you having it Done? Can you weld, have the right equipment and skill, etc? Clearly, cutting out the rust and welding in new metal "is best" if our can do it right. BUT, there's nothing wrong with what Redroadster suggested. This is a typical rust area, and there are two sheets of metal that sandwich together here, making the rust harder to treat, and the area bigger than you realize.

Since I don't know how to weld or have the equipment, 30 years ago I decided to go with the treat and fill method for some places. Sems Rust Seal, sold at body shop supply houses, is a great product that kills rust and creates a sealed primer ready surface that does not need to be painted in order to seal (that is CRITICAL as some products DO require painting). Whether you weld or fill, you're going to be using some filler no matter what. That is not the only place where it's rusting, that's just where it came through from the other side. After grinding out the hole and digging in there to check the integrity of the metal (you'll find rust, dirt etc all in that seam) and determining the extent of the rust (you can use a small size drill bit to do exploration holes along the seam, going slowly to try to penetrate the first metal sheet but not the second so you can get in between), you can carefully open seams up just a little more to fully allow the Rust Seal, sprayed in with a squirt bottle front and inside via the trunk, to flow in and kill remaining rust starts. After that you can easily fill it with a high quality filler (I like Evercoat). Done right, this should last the life of the car. No matter what, you need to get some rust killer into those seams as much as possible. That means going through the trunk and the access holes behind the rear side interior panels to dig and blow out as much stuff as possible and spray in the rust converter. This is something you're going to want to do all over the car, and if you find rust you may be drilling access holes in places. I also used a spray can rust converter to hit areas (example, the bottom rocker panels under the doors tend to rust inside, especially on the seams where dirt and moisture collect, so I drilled very small access holes to fit a small spray can straw inside so I could spray both sides and have it flow into the seams and seal the interior... it's never rusted). You may want to review some of the images posted by RCMIKE as they repaired the race car to see how the inner and outer metal come together in the wheel well.

Hope this helps.