Whether you’re building high-end Pro Touring musclecar, a concours-quality classic, or just something to roll around in on cruise night, nothing makes or breaks a restoration project like the paint job. At Precision Restorations, one of the most common questions we get asked is if a car’s existing finish can be painted over, or if it needs to be stripped down to bare metal. For cars with extensive rust damage that require sheetmetal repair, the obvious answer is to start from bare metal. However, on cars that already have a presentable paint job, the answer isn’t as clear cut. Fortunately, knowing exactly what to look for makes it easy to determine whether or not your project car’s paint finish needs to be stripped.
If cost is no object, stripping the paint down to bare metal nets the best results. That said, stripping the paint off the body—including the trunk, doors, hood, and door jambs—requires 25 to 30 hours of labor in addition to the 30 to 40 hours it takes to remove the weatherstripping, bumpers, and trim pieces. With most shops charging between $75 to $100 an hour for labor, the costs of stripping paint can add up fast. For obvious reasons, paint that is cracked, chipped, or peeling off is unsuitable to paint over and should be stripped to metal. This is caused by a range of factors including heavy oxidation, paint that’s too thick, and poor adhesion due to inadequate surface preparation. Paint that shows any of these signs must be removed by media blasting, sanding, or by re-liquefying the paint with lacquer thinner or reducer.
In instances where a car has a good, clean surface that doesn’t exhibit any of the tell-tale signs of wear, it is possible to paint over the existing finish. Typically, the only cars that have this type of surface are late-model cars with basecoat/clearcoat paint systems, or a car that has recently been restored. Below are some examples from around the shop that show old paint finishes in various states of disarray.
An old lacquer paint finish might look OK from afar, but looking at it up close reveals tiny cracks that resemble a reptile’s skin. This is referred to as “checked” paint, and a finish like this must be stripped off completely.
Paint that is too thick or has been weathered by excessive exposure to the sun often show signs of cracking. Older lacquer finishes are more prone to cracking than newer paints.
Stripping a car to bare metal is only half the battle. A poorly prepped bare metal surface will result in poor adhesion. When this happens, the paint can flake of all the way down to the metal.
After laying down a fresh coat of paint, if the top surface starts to dry more quickly than the paint beneath it, solvents trying to escape to the top can blister the paint. A high-quality paint booth precisely controls airflow to prevent this from happening.
In extreme cases of poor paint adhesion, entire chunks of paint can flake off. If a car’s surface can’t even hold on to the paint it already has, there’s no way it will support a fresh coat of paint.