Types of Stainless Trim
In early automotive trim, the stainless steel was of high quality. By the early 1950s, an extraordinary amount of stainless and aluminum trim appeared on cars but it no longer met the same standards. As a result of the Korean Conflict, quality stainless steel was in short supply, and cheaper stainless had to be found. The difference between “superior” stainless and “inferior” stainless is a high level of iron in the latter. If noticeable amounts of rust don’t give it away (have you removed trim and found the fastening clips rust-welded to the back side?), an experiment will indicate the differences in the purity of the metal. Place a magnet on a Ford Model A grill shell: it will slide off. Place it on stainless produced after the early 50’s: there will be an attraction. Mind you, not a good type of attraction. Post-Korean Conflict pieces are flash-chromed to prevent rusting owing to the high iron content. Ironically, some of the worst quality stainless is on the automobiles with the most trim, where it is meant to be the most remarkable - like late 50’s General Motors cars.
Flash-chromed stainless trim poses potentially serious problems at the start of the restoration process. Anything that has compromised the thin chrome finish - a stone ding, slight scratch, or any fracture in the chrome veneer - results in unseen damage to both the front and back surfaces of this trim. The entire piece becomes vulnerable. Water, road salt and other chemicals work their way through these slightly damaged areas, and can cause pits and corrosion beneath the chrome. This can start from the back (usually around metal clips) and work its way to the surface or start at the surface and work its way toward the back. Sometimes they meet each other. Therefore, what looks like a small imperfection can grow in size the more you try to fix it, usually by sanding the surface. Frequently, this leads to creating a hole, or a cluster of abrasions, on the surface of your trim.
Another issue with flash-chrome trim: the more you polish it, the worse it may look. The surface can take on the appearance of orange peel,akin to paint before it is color sanded. Why? The heat from polishing has melted off iron molecules, and this results in an uneven surface.
I cannot overstate the importance of the following: not all stainless trim can be restored, even if it looks straight and has no dents. If your trim has small brown spots on the surface, it is rust. Most of the time, what you see is a small indication of the damage that the piece has sustained.
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Stainless trim restoration involves removing dents, scratches, pits, and any other imperfections prior to polishing. Beginning in the 50’s during the Korean Conflict, quality stainless steel was not available to auto manufacturers, so they used a lesser quality that can be easily identified by placing a magnet on the trim. Good quality stainless will not hold a magnet, poor quality stainless will. The manufacturers would “flash chrome” their trim to keep it from rusting. Often, you see the mounting clips rust welded to the back side of stainless.
Anything that fractures, scratches, or compromises this thin chrome veneer will allow moisture and chemicals to attack the stainless causing pits and corrosion. Worse yet, corrosion can start from the back side around the clips and migrate to the front of the piece. This type of damage can not be repaired. Flash chromed trim is also much harder to properly restore because of the iron content. The more you polish it the worse it looks. The heat from polishing will throw off the iron and create a finish much like orange peel in paint.
Most of the pits and corrosion can be sanded out, but in the rare instance, it is possible to sand through an edge or corner while attempting to repair the damaged areas. Occasionally, I receive trim that has been worked on before or someone has attempted to pound out the dents, causing even more damage. I can not guarantee the results of any piece that has had previous repair or someone else’s mistakes.
Not all stainless trim can be restored. While I highly recommend restoring the trim that came on your car, it is also a good idea to start out with the best pieces possible. Any stainless trim that has holes drilled through it can be welded shut, but the heat from the welding almost always causes the piece to warp in the area of the weld.
A very high percentage of the stainless trim that I see come through my shop has been seriously damaged by improperly removing the trim from the vehicle. Not only are there depressions where each of the clips were, but there is a rebound effect caused when the clip finally releases. This rebound can cause a bulge to appear next to the depression. IT IS VERY DIFFICULT IF NOT IMPOSSIBLE TO COMPLETELY RESTORE THIS TYPE OF DAMAGE! In addition to destroying an otherwise beautifully straight piece, it also significantly increases the cost of repair. You simply can not get a screw driver and pry your trim off without ruining it.