Rust under paint -- "surface rust" or worse??

[blee]

Rust has a way of creeping up on you, doesn't it? I was looking over my car today and discovered that three doors have rust in the rear corners, right near the drain hole. So far it looks like only the outside is affected, but the rust looks like it's underneath the paint. Does this mean that it's actually rusted from inside out, or is there still the possibility that I've got surface rust? I don't want to start grinding away at it, only to see a big gaping hole in my door. :( I've read some threads where some people have resorted to looking for new doors, but I'm really hoping to at least stop the rust from getting worse first.

[632 Regal]

grind it off and treat it asap before it becomes a hole.

[Espen]

Sooner is better, grind it down to see how much damage the rust have done, I use to say that at only 1/3 of the rust is visible. If i see a 3-4cm spot of rust, i usually end up with cutting away a 10-15cm piece and weld in new fresh metal.

btw: Really fresh looking sig Jeff!

[blee]

Sigh, scary stuff. :( New trim is on the way, guess it's time to look into POR15 or other options.

[wingman]

Where is VA? Is that somewhere that they put salt on the roads in winter? I just can't imagine these cars rusting. Anyway, be careful with the grinding as doors have fairly intricate pressings. As stated you MUST neutralise the rust ASAP. You must also seek to find out why it's rustings. Check your drain holes for blockages etc etc.

[Espen]

All metal will rust sooner or later, o mystery there. And a car, wich have several variables of wear and tear will certanly rust. Maybe a stone chip started it, then water came in to bare metal and started doing its work underneath the paint.

[blee]

Northern VA = Northern Virginia, USA. Sorry for the confusion.

My guess is that the rust started with the lower trim. I won't know until the trim comes off, though. I really don't have the budget to start cutting and welding, unfortunately; my goal will be to stop the rust from spreading too violently and turning my doors into Swiss cheese. If it happens slowly, I'll be alright with that for now.

[E34-520iSE]

Do we have an agreed method of removing and treating surface rust? Do products like Jenolite etc really work? Maybe a sticky about bodywork repairs would be popular. Some e34's are 18 years old now - if they are still alive. (then there's the e28's.....)

Just a thought!

Shaun

[wingman]

My E12 stated to rust along the leading edges of the lower doors. I used a rust coverter but the stuff kept coming back. I always said that the moment I saw ANY rust on the E34 I would sell it. It's like cancer man. You can treat it but it will kill you in the end. I'm sory that you've got it.

[E34-520iSE]

So does that rust converter stuff really work then?

Shaun

[Espen]

We have something called "Norwegian Chemical Techincal institute"(NCT: http://www.chemical.no/) here, they make stuff to protect Norwegian oilrigs out in the northsea (they get "RAPED"! by saltwater every day for as long as 20 years (the oldest ones)) They also make that paint you paint big highwat bridges and stuff. NCT have been on the rust scene for as long as the oil rigs have been there, and now they have started to sell their stuff in small kits for private use. (earlier you could only buy barrels of 100liters) This have been used alot by the local Offroad drivers (you know the guys who drive around in the mud:Image (http://www.offroad.no/snitz/uploaded/P%E5l/c.jpg) and URL (www.offrad.no) ) Nothing but good experiences there (I know the site is in norwegian, and you wont understand much of it)

I bought a kit from them myself, it contains this:
-CorroFix: a "eater" wich chemically removes all rust after you have grinded/sanded all visible rust.

-Rustkiller, You apply this after the eater, this will seal the eater. If this is not a car or anythin that needs a high end result, you can drop the corrofix and go straight for the killer.

-Primer: This will give you a good surface to apply your paint on. You can mix the primer with the killer 50/50 to get even a thicker rust protection.

-ISOfix: this will "neutralize" the previous coats, so that normal 2 component car paint can be applied.

I think this sound much more serious than the "standard" rustkillers wich claim they do all in one, Remove rust, convert rust, protect from furter rust attacks, and works as a primer, that is just to much for one single product.

BTW I followed the steps above on my previous car, a Ford Sierra, I did it all myself, and now after 2 years on the road in Norwegian winters (salt!salt!salt!) still no sign of rust where I removed rust, alot of other placed on that car have started to rust though.