"Repairing Body Rust"-Part 2
Last month, we removed the trunk lid from our '58 Buick 2 door hardtop, to repair some rust bubbles. As the paint was sanded away, it became obvious the damage went far beyond a few bubbles so the rust areas were sandblasted and mig welded. We decided not to stop there. With the trunk lid off the car, it was stripped of all chrome and was sandblasted on both sides. Mo further rust or body filler was found on the topside, but underside along the lower lip by the lock assembly, the edge was eaten up with rust. The old metal was cut out and a new edge was made and mig welded in by restorer Charles Butts. The old metal can be thin in spots and it is crucial to keep the heat down on the mig to keep from blowing away good metal.
After all welding was done, a grinder was used to grind down the welds and form the area back to its original shape. The welds were sandblasted clean and metal conditioned with PPG's Metal Conditioner DX 520 SG, then fiberglassed to form a straight, even surface over the welds. This was done front and back sides, as the underside will be painted white to match the car and jack instructions (available from Buick Specialists 253-852-0584) will be glued on to give a factory appearance. Our car is tutoned-red top and bottom below the sweepspear, and middle of car (beltline down to sweepspear) white, so the firewall and trunk are white. In the reverse of this, (white top and extreme bottom) with red middle, red was used inside the trunk and on the firewall. Now with the fiberglass dry, it was sanded using an air file with 36 grit paper, then body filler was used to fill in the low places, again going over it with an air file to get a good uniform flat area. For some imperfections, a glazing putty can be used. If you're using lacquer paint, use a lacquer based filler. We are using acrylic enamel with PPG's K-200 Primer, so we used a compatible two-part putty (Evercoat #400 Glazing Putty). These products fill and sand great and really save a lot of time and work.
With the trunk almost ready for paint, we went back to the car to assess and damage to the rubber to trunk compartment. The rubber was excellent and will be re-used, but we decided to remove it (carefully) and see what was under it. What we found was badly pitted metal with minimal rust (pin holes). This time we decided since the whole car was not going to be painted, the risk of welding around the trunk opening was too great. Really, the rust didn't require it. Using a wire brush on a die grinder, all rusty scale was removed and then a good coat of POR 15 (silver) rust preventative paint was painted on with a brush. We have used this product for years and have never had rust to come back through it. It is important to cover metal area only and not put it over painted surfaces. This area will be masked around the trunk opening to protect the car's good paint, and fiberglassed, primed and painted before the rubber goes back on.
Next month, we will paint the trunk lid and reassemble. It's spring! Time to get the Buick on the road and head toward the car shows. See you next month. Keep 'em driving!