freakin' chicago winters. now what can I do about this subframe rust?....
sub-frame rust - what can I do?...
- Thread starter sky jumper
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- Sep 28, 2002
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Grind, weld, paint. I just played Mr. Hold-it for my buddy as he spruced up a 68 Camaro for the lucky owner. The body mounts were all in sad shape. A mig welder and time fixed it up real prutty. My pal, a 63 year old ex-racer/builder who everyone takes their vintage stuff to makes it look easy.
Some cars are actually pretty easy to swap these things. Look up an interchange and sometimes you can get a few years' newer model, and, if lucky, one from down south.
I've done it on a saturn in my driveway with only jackstands and a 2x4 across the fenders to hold the motor up.
I've done it on a saturn in my driveway with only jackstands and a 2x4 across the fenders to hold the motor up.
ducktape?
i kid i kid....
i kid i kid....
Rust belt people should swap cars with non rust belt people after 150,000 miles. That would even out the wear.
I get my cars oil undercoated every fall,they both look new on the underside,also never had to replace a fuel or brakeline,and the E-cable never seized.
do any of you have experience with naval jelly, or the permatex rust treatment? there's also a loctite product that is supposed to do a chemical bluing like on gun barrels, but it doesn't seem like it would work here. I don't think welding is an option for me. thoughts?
Don't know what I am doing right. I live in the salt belt, and I have traded off an 11 year old Pontiac Phoenix and a 10 years old Grand Am with no rust. I never had either rust proofed and wasn't particularly good about washing and waxing.
Now about my 77 LUV. You can buy a welder starting at about $100.
Now about my 77 LUV. You can buy a welder starting at about $100.
Kestas
Staff member
For the patch job, you should get away with the auto store rustproofing. For the whole car, get it done professionally. A patch paint job is never as good as the treatment metal receives at the factory, hence the need for rustproofing. The factory finish for metal often includes an etch treatment, galvanneal, phosphating, and e-coat before paint.
Kestas
Staff member
I agree that prevention is the key. The money spent on rustproofing a car is a lot less than what you'll spend dealing with issues like you have here.
Unless the rust has gone through to the other side, you may sandblast the area and repaint/rustproof.
Unless the rust has gone through to the other side, you may sandblast the area and repaint/rustproof.
when you say rustproofed, are you talking about those spray on undercoatings you can get at the auto store?
Kestas
Staff member
Frankiee, it's not that easy. Sometimes the corrosion cell can be as simple as a pit in the metal.
No, it is not easy. That is why once a car has rust it is akin to having a diesese. Thats why I said its a tough thing to do. A person would have to cover every square inch of the whole vehicle.
Covering the affected area will be a patch. It will still rust under that patch because the exposed cathode end will still enable the electrons to flow.
Covering the affected area will be a patch. It will still rust under that patch because the exposed cathode end will still enable the electrons to flow.
so what would I look for to find this "cathode"? just another patch of rust? would it be deep like this or just surface? would a poor ground at the battery affect this?
Kestas
Staff member
Frakiee, I don't know how to put this delicately, but your posts indicate ignorance on the practical mechanisms of corrosion.
I'm not going to start posting a long-winded discussion on exactly how corrosion starts and progresses, but in practical terms, removing the existing corrosion and covering it to protect it from the solution that enables corrosive activity WILL stop the area from further corrosion.
Just a small disturbance in the metallurgy of steel - such as a spot weld - can set up an electrolytic cell (cathode and anode) enabling corrosion. There doesn't need to be any search for the elusive cathode.
Skyjumper, by chance is this corrosion somewhere under the battery?
[ May 20, 2006, 05:42 PM: Message edited by: Kestas ]
I'm not going to start posting a long-winded discussion on exactly how corrosion starts and progresses, but in practical terms, removing the existing corrosion and covering it to protect it from the solution that enables corrosive activity WILL stop the area from further corrosion.
Just a small disturbance in the metallurgy of steel - such as a spot weld - can set up an electrolytic cell (cathode and anode) enabling corrosion. There doesn't need to be any search for the elusive cathode.
Skyjumper, by chance is this corrosion somewhere under the battery?
[ May 20, 2006, 05:42 PM: Message edited by: Kestas ]
The way to avoid galvanic action is to galvanize the metal. There are several cold galvanizing products out there that are sprayable and brushable.
One of the nice things about zinc on steel is that it "heals" itself. When galvanic action begins due to a pit or scratch, the zinc galvanically migrates to the imperfection and protects it.
The only thing to keep in mind is that the zinc has to be in electrical contact with the steel - you can't put it over paint or dirt and get protection.
I used to use it on welds when repairing old cars, but began coating inside panels, the outside of bolts and nuts under the car, and so on when I saw what it did.
One of the nice things about zinc on steel is that it "heals" itself. When galvanic action begins due to a pit or scratch, the zinc galvanically migrates to the imperfection and protects it.
The only thing to keep in mind is that the zinc has to be in electrical contact with the steel - you can't put it over paint or dirt and get protection.
I used to use it on welds when repairing old cars, but began coating inside panels, the outside of bolts and nuts under the car, and so on when I saw what it did.
no - it's where the subframe bolts up to the unibody, underneath the passenger seat.
here's my current plan. please tell me if you see room for improvement:
1) wire brush the heck out of the area. then course sand.
2) use permatex naval jelly to dissolve any leftover rust.
3) paint with POR15
4) cover with spray on undercoating
what do you think?
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