Rust: The most feared word in the restoration hobby. Most of us are somewhat mechanical and could probably rebuild an engine or at least swap in a crate engine. But when it comes time to replace the rusted-out floorboards or patch up a fender, few of us have the necessary skills and/or equipment to complete the repair. Luckily, if the rust isn't too bad, there's a non-welding solution that anyone can handle.
RestoMotive Laboratories has developed products to help the do-it-yourselfer combat minor rust-out and prevent any further rust from occurring. When it came time to repair a water leak in the rear glass area of a '70 Monte Carlo (an area notorious for rust), we ordered a POR-15 starter kit and some putty. We completed the repair in three days, which might seem like a long time, but we wanted to make sure the products had enough time to dry between steps.
We started our repair by removing the stainless window trim moldings using the required tool. This tool is a must for this job and is available at most auto part stores for a few bucks.
Here's what we found: Dirt and debris that gets trapped in the channel between the glass and header panel holds moisture that eventually rusts out the metal. You'd have a hard time finding an early A-body that didn't have some rust in this area.
Once we had the glass removed, we used a wire brush and a flat-bladed screwdriver to scrape the loose rust away. We also trimmed the vinyl top back because although we are not ready to replace it now, we didn't want the window seal to overlap it when the glass was reinstalled.
Our rust was not very bad, just a few holes that were smaller than a quarter-inch, so we should have no problem using the POR-15 starter kit and putty. It came with everything we needed to repair the small rust holes with the exception of sandpaper and steel wool pads.
We cleaned the channel with the Marine Clean degreaser/cleaner and a synthetic steel wool pad and wiped it clean with a rag.
We then applied the Metal Ready with one of the supplied brushes to the bare metal and rusted areas and let it sit for approximately 20 minutes making sure that it stayed damp. The Metal Ready will neutralize the rust and etch the metal for better paint adhesion. A water-dampened rag, followed by a clean dry rag, was then used to neutralize the Metal Ready and get the channel ready for paint.
The rusted areas were then painted with the POR-15 paint. Notice that we were repairing minimal rust holes. If you have substantial rust, you might be able to repair it with their Floor Pan and Trunk Resto Kit which includes some fiberglass sheets to cover larger holes.
We allowed the paint to dry overnight and then prepared the putty to fill the holes by cutting off two equal amounts and then thoroughly kneading them together. It's very important that the putty is mixed completely-we added a little bit of water to make it easier.
With the putty sanded smooth, we sanded the entire window channel and painted it all with a coat of the POR-15 paint to make sure that our repair would last. Once the paint dried, the repaired areas were almost undetectable and should last another 30 years.
Once the putty is mixed, it stays workable for about an hour, more than enough time to complete the repair. We simply used our fingers to push the putty into the channel paying particular attention to the areas where the rust holes where.
We let the putty sit overnight to ensure that it had dried thoroughly and then sanded it with some 80-grit sandpaper, followed by some 220-grit. Once we started sanding, the importance of smoothing out the putty while it's still pliable became very apparent. This part is tough.