Long(er) Term Fix for a New Kid

[motoxnate]

Hi everybody, I'm fairly new here and to the paint / restoration trade in general. My first project was painting a set of side skirts to match my car, which took a lot of time and a bit of rework after some mistakes, but I made it happen.

My car has a bit of rust that started and was bondo-ed by the previous owner on the rear fender well. Last fall I realized there was bondo and chipped it out, revealing a small gap (~5mm) in between where the outer panel meets the inner panel. However, the rust itself is fairly local and seems to be completely contained within a ~2 square inch area horizontally.

I don't have the welding experience to cut this out and repair it myself (also a patch panel for this fender is very difficult to find). A while back I bought a quart of USC All-Metal filler because I had heard good things about it and its expansion properties. Right now, I'm leaning toward the following process:
1. Spot blasting / wire wheeling all of the rust out.
2. Apply Ospho to whatever surface rust I can't reach in small pits.
3. Paint the whole area epoxy primer to completely seal the metal.
4. Use the all-metal filler to fill in the seam and smooth over the outer fender a little bit.
5. Top the outer surface with evercoat gold for a good finish.
6. If this seems like a good fix - have a friend who has a body shop either blend or repaint the entire panel. I'm worried about the blend not looking good or fading.

Does this selection of product / use sound like it would last a good while? I know that since it is filler, it's not as permanent as welding, but the area that needs filler is mostly internal to the body and my idea is that epoxy primer would seal the metal, so the filler isn't as much of a worry with future rust.

Attached are a few photos of what's going on... sorry I don't have any of the gap where the seam has rusted out.

 

[MJM]

What state are you located in? If you're in my state, Missouri, I could tack weld that crack up for you.

 

[motoxnate]

What state are you located in? If you're in my state, Missouri, I could tack weld that crack up for you.

Thanks so much! Unfortunately I am in Southern Connecticut

 

[Chris_Hamilton]

That's not surface rust. that's rot and once you start trying to remove the rust you will find there will be nothing left in that area. The gap/crack is because it has corroded away. Fix you described will last for a while (months?) but the only real long term solution is to cut it out and replace it with new metal. You will find that the inner panel behind it (if there is one I don't know what you are working on) is rusted as well. Typical road salt type corrosion. What make of vehicle? I can't tell from the pics.
Any type of "repair" other than new metal there is a stopgap, not a long term solution. It might last a year, it might last only a month.
We can walk you through a proper repair. MIG welders are cheap and a Monkey can MIG weld so you can too.

 

[dhutton01]

Although not as good as welding you could use panel adhesive to glue in a small patch from behind and then bodywork it. Certainly better than packing it full of filler imho.

Don

 

[motoxnate]

That's not surface rust. that's rot and once you start trying to remove the rust you will find there will be nothing left in that area. The gap/crack is because it has corroded away. Fix you described will last for a while (months?) but the only real long term solution is to cut it out and replace it with new metal. You will find that the inner panel behind it (if there is one I don't know what you are working on) is rusted as well. Typical road salt type corrosion. What make of vehicle? I can't tell from the pics.
Any type of "repair" other than new metal there is a stopgap, not a long term solution. It might last a year, it might last only a month.
We can walk you through a proper repair. MIG welders are cheap and a Monkey can MIG weld so you can too.

Thanks for the reply Chris, I appreciate it.
It's a 2004 Subaru WRX and the best way I can illustrate where the panel meets is like this: ---\|
If you imagine the --- is the top of the wheel well, the bottom of the V shape is rusted where the vertical line is the outer panel.

I do actually have a MIG welder and I am okay with it, I just don't seem to trust myself enough to work on the outside panels of my baby. You think I should cut out that small section and weld something in to fit?

Thanks!
Nate

 

[crashtech]

Have you had that car on a hoist and poked around real good underneath? I like Subarus but they don't last where there is road salt.

 

[motoxnate]

Have you had that car on a hoist and poked around real good underneath? I like Subarus but they don't last where there is road salt.

Yes, I’ve had the transmission out twice along with the whole driveline and exhaust. Overall the body isn’t horrible, it’s mainly the wheel arch on the passenger side specifically and the rear differential outrigger on the same side. The diff mount i can deal with, I don’t mind welding under the car where it doesn’t have to look pretty I already welded a small piece of 1/8” steel over one of the jack points, near the outrigger.

 

[MJM]

Although not as good as welding you could use panel adhesive to glue in a small patch from behind and then bodywork it. Certainly better than packing it full of filler imho.

Don

Good bandaid suggestion right there ^^^....and to add to that suggestion, use fiberglass filler to fill up the depression from the backer plate, then finish off with regular filler.