To bondo or not to bondo?

[Jon O.]

As some of you have seen in my other posts, I have a 72 Newport. It has a little bit of rust at the bottoms of the quarter panels, (no holes yet.) It also has a few small spots of chipped paint on the nose of the hood (not rusted yet.) The car has it's original paint. My question is should I fix these problems before they get worse or leave them alone because of original paint. The problems are still small enough where its hard to spot glancing at the car.

 

[oliver]

Now is the time to get to it. It will only get worse, and quickly so if the car is stored outdoors.
Don't worry too much about original paint. You can have some paint made from your paint code and do some touch ups that really will not show much, especially at the bottom of the rear quarter panels. Left untreated, these rust areas will become big gaping holes that will require major metal fabrication to repair.
This being said, bondo is not the answer. First, you'd want to clean/sand these areas and assess the extent of rust damage (any small rust pinholes will suddenly become larger) which will determine how it should be treated.
When it comes to your rear quarter panels, remember that they rot mostly from the inside; not so much from the outside.

 

[bluefury361]

Bondo is for achieving a good flat surface before final refinishing, not for filling holes or dents. Correctly applied it works great.
It's ok to touch up paint chips, like on the hood. But lower 1/4 areas need to be stripped to the metal to determine what needs to be done. If a tap with a screw driver or punch penetrates then it's time for some metal repair. You can still fix and blend color to retain original condition of the entire car.

 

[rapidtrans]

It was not rare to find Bondo under a factory paint finish. A buddy's '70 Challenger purple paint had flaked-off by '73. During the repaint prep he found quite a bit Bondo on the passenger door. When i worked at Dodge Main i saw it often used as a last resort for panel alignment.
I would fiberglass any holes before using Bondo back in the old days. We couldn't afford or had the the ability to replace sheet metal.

 

[Jon O.]

Bondo is for achieving a good flat surface before final refinishing, not for filling holes or dents. Corectly applied it works great.
It's ok to touch up paint chips, like on the hood. But lower 1/4 areas need to be stripped to the metal to determine what need to be done. If a tap with a screw driver or punch penetrates then it's time for some metal repair. You can still fix and blend color to retain original condition of the entire car.

of course stripping to the metal first, Sorry i didnt explain too well. Im looking for an explanation on what I should do here. The rust is not large enough to punch holes. So I should sand to metal, should I then bondo? or should I just paint over it? Im looking for what will last the longest. Most of it is just lightly bubbly, creeping through the paint.

 

[oliver]

Bubbly = most likely perforating rust under the bubbles

 

[Jon O.]

Bubbly = most likely perforating rust under the bubbles

Sadly a better look tells me that you are right. not very much of it, but it is there. Is there anything I can do besides welding in a new patch?

 

[oliver]

Would you be able to post close-ups of the specific areas you're talking about?

 

[Yatzee]

As some of you have seen in my other posts, I have a 72 Newport. It has a little bit of rust at the bottoms of the quarter panels, (no holes yet.) It also has a few small spots of chipped paint on the nose of the hood (not rusted yet.) The car has it's original paint. My question is should I fix these problems before they get worse or leave them alone because of original paint. The problems are still small enough where its hard to spot glancing at the car.

You can probably do a real close paint match these days on the bottom of the quarters that will not be noticeable due to the way the light hits it. After a thorough rust removal by what ever means, you can coat the metal lightly with fiberglass epoxy only and sand glass smooth. The epoxy will seal the underlying metal from further rusting. Because the epoxy is so liquid ( unlike bond) it will go into and seal the smallest of "pocs" thus preventing further oxidization while offering a great surface for filler.

 

[70Tom]

The rust is not large enough to punch holes. Im looking for what will last the longest. Most of it is just lightly bubbly, creeping through the paint.

Oh, you'd be surprised.

This might sound like a bad idea, but it's not. Get a small flat head screwdriver or some pointy punch tool and poke into the bubble. You want to see if it is merely surface rust, or if, as other suggest, the rot is starting from the back.

I had both fender with similar type rust bubbles that you appear to be describing. One ended up poking all the way through. After cutting out a small piece, it was smart I did because the rot behind the fender brace was pretty bad. I was able to clean it out, spray some rust encapsulator on it, and then weld in a new small piece of metal. The other fender ended up just being surface rust. As I was sanding down the whole car to bare metal, that was the process with that one. Needed no work.

And honestly, just weld in a new patch. Half-assing it just doesn't make any sense. I'm sure you can find someone local who can weld in a couple of small patch pieces for you if you can't do it. From there you grind down the welds, and then throw a very thin layer of filler over it to smooth it all out.

 

[Jon O.]

Oh, you'd be surprised.

This might sound like a bad idea, but it's not. Get a small flat head screwdriver or some pointy punch tool and poke into the bubble. You want to see if it is merely surface rust, or if, as other suggest, the rot is starting from the back.

I had both fender with similar type rust bubbles that you appear to be describing. One ended up poking all the way through. After cutting out a small piece, it was smart I did because the rot behind the fender brace was pretty bad. I was able to clean it out, spray some rust encapsulator on it, and then weld in a new small piece of metal. The other fender ended up just being surface rust. As I was sanding down the whole car to bare metal, that was the process with that one. Needed no work.

And honestly, just weld in a new patch. Half-assing it just doesn't make any sense. I'm sure you can find someone local who can weld in a couple of small patch pieces for you if you can't do it. From there you grind down the welds, and then throw a very thin layer of filler over it to smooth it all out.

I doubt it started in the back, the car has a heavy coating underneath. There isnt any rust on the underside of the car. And by the way I am a teenager with hardly any money. For me it is either do a good half-*** job, or let a survivor car rust away.

 

[rapidtrans]

The fiberglass will fill the pin holes and provide you a waterproof base. Bondo is not waterproof and rust will re-appear. As mentioned above it's best used just for leveling and only in thin amounts. Anymore than say 1/8" its prone to cracking.

 

[oliver]

I doubt it started in the back, the car has a heavy coating underneath. There isnt any rust on the underside of the car. And by the way I am a teenager with hardly any money. For me it is either do a good half-*** job, or let a survivor car rust away.

No, not on the underside. Inside the trunk area: the cavity between the bottom of the quarter panels and the trunk floor extension. That is usually where rot begins

 

[Jon O.]

No, not on the underside. Inside the trunk area: the cavity between the bottom of the quarter panels and the trunk floor extension. That is usually where rot begins

For a short time the trunk did leak some water. The problem has been fixed, but it was there long enough to leave small rust stains new enough that they just wiped off. I think you are right then. Do you think there may still be water sitting at the bottom of the panel?

 

[oliver]

Do you think there may still be water sitting at the bottom of the panel?[/QUOTE]

Water or not, over the years with humidity, condensation and lack of adequate rust protection in that specific area, it's always where quarter panel rust begins

 

[Jon O.]

Do you think there may still be water sitting at the bottom of the panel?

Water or not, over the years with humidity, condensation and lack of adequate rust protection in that specific area, it's always where quarter panel rust begins[/QUOTE]

thank you for your help!

 

[oliver]

on top of that, people had a tendency to stuff rags and other crap in these areas, which only compounds the problem

 

[GJS]

Just to give you an idea, this is next to the rear window trim on my Monaco. There's no way water "sat" on this spot but simply due to humidity there is rust through. Chrysler was good at many -a- things, sheet metal selection wasn't one.

For your 1/4 rot, get down in those pockets in the trunk and clean the crap out of them as there is definatelt crap to be cleaned out. As has been said above, get to chipping away at any bubbles, the longer those bubbles hold in moisture, the worse it will get. Take the outside (and inside as best you can) down to bare metal and note how far the weakness in the metal extends out from the hole.

Best thing you can do is cut the weak area out and have it patched up with good ole metal. I know you likely don't want to hear that any more than I do when I find a new hole in my car but it's the damned truth.

Bondo as the soul component of body work never works out. One can be "good" at it as in it doesn't turn out looking like chewed bubble gum with paint on it but it never lasts....
Like, uh:

 

[traintech55]

Being a teenager is a great time to learn about cars in general. Most of us here started at that age and learned skills that have lasted a lifetime. Don't give up, and don't be afraid to ask questions.
As for your Newport if you can get your hands on a sandblaster, that is the best way to get to clean metal to repair. Make sure you work on the insìde and outside.

 

[bluefury361]

Any rust area has to be removed to clean metal. Use a spray bottle to saturate the inner side of the panel with rust convertor. This will stop any further rust spread.

There are metal filler products that work good for small areas like yours..... Example.....

metal filler for rust holes - Google Search