View Full Version : Question for Autobody Techs

05-08-2012, 12:57 AM
I know there are a lot of talented people with lots of experience, so please post your comment!!!

So here's my question

I did some rust repair on a buick. the bottom of the doors where the rubber weatherstripping runs. Looked like factory for about a year, now the rust is back showing up just above the rubber....

Here are the products I used:

Rotac scotch discs
*Rust Converter (Makes rust turn to black primer)
scratch filler puddy
*Basic Primer (no-name General store) about 4 coats
*Color Paint (4 coats)
*Clear Coat (3 coats)

I sanded and removed as much rust as possible, and the remaining pitted and surface rust, I used the rust converter on, then cleaned it with MEK or Isopropyl, let it dry then applied bondo...primer...etc.

Where did I most likely go wrong? I know there are lots of possibilities, but I'd like to learn, so what is common for rust to slowly return after repairs?

05-08-2012, 01:12 AM
You didn't necessarily do anything wrong... it's just that without actually re-skinning the door the rust will always come back since it's inside the door itself where the two panels meet each other and are pinched together. There are also differing opinions on rust encapsulation vs conversion. Some guys on here swear by Eastwood products... I've used Por-15 on my car and it's done a pretty good job. Either way it's a never ending battle.

05-08-2012, 05:04 PM
I mean, you got a year out of the repair, do it again and enjoy another year. as Silventwing Said, unless you cut out all the rusty metal, it will come back. If you got a year out of rust converter and bondo it doesn't sound like the rust is bad enough to cut the metal out unless this is a car you are looking to put the $$$ into to keep for awhile. Only you can make that call.

05-08-2012, 05:05 PM
fwiw, I've sealed my door s with POR 15 on the last few used cars I've had with good results.

05-21-2012, 08:31 AM
Thanks for the further links Cyrus and it is also true that minor damage can actually signal larger problems. So to sort out these problems, professional auto body repair is the best.