Discussion
You can mess around with rust and use every rust treatment known to man and it'll still come back unless you clear it back to fresh metal.
Rust is like a cancer. Grind it back until the metal is shiny and new. If you can't because it has penetrated (and most rust comes through from the inside), then the only solution is to cut it out and weld in a new piece of metal.
I have restored more cars than I care to remember and believe me, you can't kill it or stop it because it just won't last. If you want a proper job, fresh metal is the only answer. If you want to hide it for a while, then the likes of Jenolite or other such rust treatments will hold off the worst for a few months, maybe even a year.
Rust is like a cancer. Grind it back until the metal is shiny and new. If you can't because it has penetrated (and most rust comes through from the inside), then the only solution is to cut it out and weld in a new piece of metal.
I have restored more cars than I care to remember and believe me, you can't kill it or stop it because it just won't last. If you want a proper job, fresh metal is the only answer. If you want to hide it for a while, then the likes of Jenolite or other such rust treatments will hold off the worst for a few months, maybe even a year.
Some e36's are prone to this problem. It has to be down to the products used in manufacture. Paint primers and sealers have progressed a long way over the last 10 years and manufacturers such as BMW have taken advantage of new products.
This kind of problem on a newer car is rare and usually a sign of a fault in manufacture. Regular washing with a non acidic car shampoo and thorough rinsing with clean water usually guards against this kind of deterioration.
This kind of problem on a newer car is rare and usually a sign of a fault in manufacture. Regular washing with a non acidic car shampoo and thorough rinsing with clean water usually guards against this kind of deterioration.
Talkwrench,
Sadly due to finances I think we will be getting a car of similar age (A6 avant or 5 series touring). Event with regular washing with Autoglym shampoo these have developed over the last 12 months. Will ask the garage to take a look when it is next serviced (should be soon).
Sadly due to finances I think we will be getting a car of similar age (A6 avant or 5 series touring). Event with regular washing with Autoglym shampoo these have developed over the last 12 months. Will ask the garage to take a look when it is next serviced (should be soon).
I've never seen a similar problem on an Audi of the same era. Audi were ahead of the game with rust proofing, galvanised body shells etc.
The same problem does often materialise on 5 series, unfortunately.
It really is a case of checking an individual car to see if the problem is in evidence. If not, then it may never happen. It is probably paint that is slightly porous and a little too thin on panel edges that causes this to happen. Some cars may well have enough paint on them to be ok!
A generous application of a good wax, not forgetting the shut lines and panel edges may well help.
The same problem does often materialise on 5 series, unfortunately.
It really is a case of checking an individual car to see if the problem is in evidence. If not, then it may never happen. It is probably paint that is slightly porous and a little too thin on panel edges that causes this to happen. Some cars may well have enough paint on them to be ok!
A generous application of a good wax, not forgetting the shut lines and panel edges may well help.
I did a little investigation and had an ineresting chat with an old guy who recently retired from a BMW body shop. The paint problems of the 90's are, indeed, caused by thin paint application at the factory just as I suspected.
The paint and primer are so thin that, over time, the paint becomes porous and the panels rust, particularly at the edges. Any kind of slight damage such as stone chips and scratches result in rust. This is exacerbated by the fact that the paint used has poor 'self heal' properties and the metal is left exposed. The issue affects many 3 and 5 series cars, is less of a problem on 7 series and is unknown on 8 series where final paint finish was subject to different quality control.
He also mentioned the problem of lacquer flaking off basecoat. Another factory based problem!
The paint and primer are so thin that, over time, the paint becomes porous and the panels rust, particularly at the edges. Any kind of slight damage such as stone chips and scratches result in rust. This is exacerbated by the fact that the paint used has poor 'self heal' properties and the metal is left exposed. The issue affects many 3 and 5 series cars, is less of a problem on 7 series and is unknown on 8 series where final paint finish was subject to different quality control.
He also mentioned the problem of lacquer flaking off basecoat. Another factory based problem!
All this talk of rust got me to look at my E46 (99) and have found a tiny spot above a wheel arch, however it is spreading under the paint like a spider, about the size of a watch button. Would it work if I removed the paint with a very small wire brush (as on the top of Saab touch up sticks)and repair with touch up stick and laquer?
Edited by 5CYL on Sunday 3rd June 18:18
Edited by 5CYL on Sunday 3rd June 18:18
My E36 ('99 T) has some rust on it. Two spots on the bottom edge of the boot lid, one spot just above the plastic rubbing strip on the leading edge of the driver's side door, along the edge of the bonnet on both sides and a small patch in the curve at the trailing edge of the passenger side rear window. I'd like to get it sorted but if it's the result of thin and porous paint then might it just start appearing elsewhere giving me more work to have done? Ideally I'd like a bare-metal respray but for a car of this vaule it isn't really worth it other than if I were rich and wanted to do it for sentimental reasons. While my sentiments towards the car are highly favourable my wallet won't stretch to a major restoration!
5CYL said:
All this talk of rust got me to look at my E46 (99) and have found a tiny spot above a wheel arch, however it is spreading under the paint like a spider, about the size of a watch button. Would it work if I removed the paint with a very small wire brush (as on the top of Saab touch up sticks)and repair with touch up stick and laquer?
This sounds typical of a stone chip taking hold and spreading under the paint. If you tackle this with a tiny wire brush, you really have to make sure you remove all evidence of the rust. It is very difficult to make any kind of permanent repair with this method but you can delay the rust process. Use jenolite or some other rust converter before applying the touch up paint.MitchT said:
My E36 ('99 T) has some rust on it. etc... etc...
Tricky one because of the location of the rust and the colour of your car. It may be possible to blend in over the bonnet and front wing but if you have much in the way of stone chips etc., I'd have the bonnet, front wings and spoiler resprayed.The rust at the rear needs taking back to good metal and filling/blending. No real need for a bare metal respray with your car. the original paint isn't particularly thick and a further application will not make the paint prohibitively thick.
Edited by Talkwrench on Monday 4th June 11:06
Talkwrench said:
5CYL said:
All this talk of rust got me to look at my E46 (99) and have found a tiny spot above a wheel arch, however it is spreading under the paint like a spider, about the size of a watch button. Would it work if I removed the paint with a very small wire brush (as on the top of Saab touch up sticks)and repair with touch up stick and laquer?
This sounds typical of a stone chip taking hold and spreading under the paint. If you tackle this with a tiny wire brush, you really have to make sure you remove all evidence of the rust. It is very difficult to make any kind of permanent repair with this method but you can delay the rust process. Use jenolite or some other rust converter before applying the touch up paint.
Talkwrench said:
MitchT said:
My E36 ('99 T) has some rust on it. etc... etc...
Tricky one because of the location of the rust and the colour of your car. It may be possible to blend in over the bonnet and front wing but if you have much in the way of stone chips etc., I'd have the bonnet, front wings and spoiler resprayed.The rust at the rear needs taking back to good metal and filling/blending. No real need for a bare metal respray with your car. the original paint isn't particularly thick and a further application will not make the paint prohibitively thick.
Edited by Talkwrench on Monday 4th June 11:06
One of the wings on my BMW is relatively new as the previous one was bent when someone reversed into the corner of my car in a car park! I had it repaired at Just Car Clinic in Bradford - I don't know how much paint they put on the new wing compared to what BMW would have put on the car in the factory, so I don't know whether it would need respraying to thicken the paint up. Normally I'd have insisted on an 'Official BMW' repairer, but BMW did a previous repair after a minor accident and made a complete mess of it which required several remedial actions over the course of a year, so I figured if the so-called experts couldn't get it right then it might as well go where the insurance company wanted it to if anything else ever happened. When it did, JCC did a fine job - much better than the lousy effort by BMW's 'official' body shop!
I suppose it might be worth getting the rust done sooner rather than later with the option of doing a whole respray later. I still enjoy seeing the car across a car park as I walk towards it, particularly when it's really clean, so it always make me a bit sad when I get closer and see the bits that need sorting out.
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