1953 RIVIERA RUST REPAIR AND PRIMER
The work on our '53 Buick Roadmaster Riviera 2 door hardtop continues. With the car stripped to the metal (see Issue #8-04), we were ready to inspect for any body damage or rust out that would have to be repaired. The body was basically solid, with some rust in left and right rear quarter panels, pinholes around the headlights, and holes in the front fender channels.
The freshly sandblasted metal was wiped down with PPG's metal prep, washed off, and the car shot with epoxy sealer to protect it from rusting and provide a good bond with our primer later. We left the rust areas bare metal for our repair work. Our first repair was the front fender channel. The bracket for the radiator was removed, as were the fender bolts. Using a die grinder with a coarse wire brush, all loose scale was removed, leaving clean rusted holes. Longtime welder and restorer Don Pennington cut out the affected areas and replaced them with new pieces of 18 gauge cold rolled steel. After fitting them into place, he tacked them with a MIG welder, then meticulously welded around each piece, leaving a space between each weld to eliminate metal warpage. Eventually all spaces were filled and the pieces were solidly in place. Using a grinder, he ground the metal down until it conformed to the fender's original shape. All that was needed now was a little body work and primer. The holes around the headlights were small, and we decided to clean them out and just weld them up. The amperage and wire feed were cut down as low as possible to protect from blowing holes through the metal, but hot enough to still get a good weld. Hesitation is another consideration when MIG welding. Moving at a consistent rate will provide a good flowing weld, but stopping too long in one place could result in blowing holes in the metal.
After the welding was finished, Don used a grinder to smooth and flatten out the surface. The most rust damage was in the rear quarter panels. The rusted area would have to be cut out and new panels welded in. To fabricate the new right panel, we used a piece of thin cardboard to make a template by laying it against the rear quarter and tracing about 2" to the outside of the rusted area. Using a die grinder fitted with a wafer wheel, we cut out the bad metal. A new piece of 18-gauge steel was laid out and we traced the cardboard template onto it and cut out the panel, which was identical to the old rusty one we removed. We set the new panel in place and held it with clamps, then tack-welded it, skipping around until all areas were welded in a smooth, continuous weld. A condition to be aware of when welding is "porosity". This occurs when there is too much air moving in the shop, such as a fan blowing on the weld, which blows the gas shield away from the weld and allows oxygen to contaminate it, resulting in a porous weld with little strength.
We have had excellent results with the rust preventative POR-15. We always brush some on the back side of a panel that is not to be painted to protect it from rusting. Any primer must be applied while it is still tacky, since it will not bond after the POR-15 dries.
With the panel welded into place, we ground down the welds using a die grinder with wire brush to clean the weld, metal-prepped the panel and primed it. All that was left was minor ding repair before the metal work was considered complete.
For our primer, we chose PPG's K-200 High Build Primer. It goes on thick, is easy to sand and bonds nicely with the epoxy that had previously been applied. We had some K-200 in stock, but it is no longer available and has been replaced with K-38, also a high-build primer, and K-201 catalyst.
With the car in primer and the chrome away being plated, it was a good time to pull the engine and go through the mechanics. Join us next month when the hood comes off and the engine comes out. You won't believe what we found! Enjoy your cars...keep 'em driving!