The guy who did the autoglass on the '69 Camaro build asked me to repair some rust on his 1999 GMC Trailblazer and as he also does the glass in my projects, I thought I'd be a good car buddy and do it for him over the long weekend...
Didn't look too bad to start with....
But like the Foreigner song, Three dressed up as a nine - the closet you got...the worser she looked!
I noticed the door was out of alignment to the dog leg and rocker - so I took photo of that to see if we couldn't get that better off in the end as well -
So out came the cutting tools and safety gear
With the replacement rocker measured thrice and marked -
I first cut the rocker - a bit bigger than needed - because its always easier to trim is down than having to add pieces later
On the vehicle, I did the opposite, by cutting out the minimum amount - to see what was behind the rust. What's that in behind the rust? Why it's a snoot-full of dirt of course!
Packed full of moisture-holding dirt, which gets in through gaps and drain holes, rusting out the rocker from the inside -
Once the outer skin was off, I could see that the inner rocker was also rusted through,
so with a masking tape line as a guide, off it went as well.
Which included mock up, reshaping and cutting to a precise fit..
Once it was the exact right shape and dimension, I soaked any remaining surface rust with POR's MetalReady and left to work overnight. This solution turns iron oxide (rust) to iron oxite, which is an inter substance. It also helps make metal more conductive for welding by depositing Zinc Phosphate.
The next day, with everything prepared properly and dried, welding the inner panel ensued. But before welding, I hung a welding blanket across the door opening to protect the interior from weld splatter - or worse!
Here the innner is welded solid, using a back and forth spot-weld pattern so as not to overheat it, which can lead to warping, burn through and fire hazard.
With the inner welded on, I trimmed and fit the outer panel so as to ensure it would fit over the finished the inner
Then, plug-weld holes where drilled in the new outer panel,
so as to attach it at the bottom, to the new inner panel
Prior to welding on the outer panel, I coated the new inner panel - as well as the original surrounding metal - with POR15, for maximum rust protection
Both back and front
Then, the outer panel was welded in, little by little, ensuring it would line up with the body and door
The lower connecting edge of the wheel-well also needed attention, taking me 3 tries to get right!
With everything set and welded, the welds were ground down and the entire panel cleaned up, ready for a skim coat of filler
A skif a filler was next to finish it off -
Tomorrow I'll do a final sand of the filer, then put some more POR-15 on it as well as on the bottom of the rockers so they can either stay black, or can be painted at a later date.
So, a total of 8 hours, over 3 days, and the rotted out rocker was repaired in and out. This repair will last the life of the vehicle - and likely longer, since I made a point to shape the wheel-well connection so as to allow water and dirt to drain out more easily. It's not often I spend my time on 'later model' rust repairs, but once in a while I don't mind helping another car-guy out. It's one of the many things that makes our hobby so much fun!