Here's the piece before I started the repair. You can see there are no cracks but rather frightening denting. We can make it like new, we have the technology!
You Can See a Progessive Picture of the Process Here
The first step is to get the part reasonably close to the original shape by moving the metal back. I use pretty much anything that will work to shape the piece. In this case I used a homemade pick, screwdriver, and light hammer. Work the dents out until the part has the basic shape it originally had. This will have to be very close to original as we will want it perfectly smooth when done. Just tap the dents out against a vise or other hard surface. Here's a pic of the piece after the initial straightening and the low tech tools I used.
The next step is to start smoothing the surface using a file. You will have to tap low spots as you file to bring up the surface to the filing plane. The process is called 'picking and filing'. When you are done the surface should be flat with a consistant filed surface.
Now I switch to using the dual action sander and 400 grit paper. Use the sander on grind rather than the DA setting. Smooth out the surface being careful to keep the surface flat as well. Don't create dips. You're done when all the filing marks are gone. Please keep in mind that the metal is only so thick so don't grind any more than you need!
From here it's best to switch back to working by hand. Using 800 grit wet/dry sandpaper sand the surface by hand. Using lots of lubricant such as WD40 will really help. Use long strokes to limit creating waves. Sand only in one direction with the length of the trim. You are done when all the 400 grit scratches are gone. Most of the time this is the final step before going to the buffer. But some stainless is harder and will need a 1000 or 1200 grit sanding before polishing.
The final step is using the buffer. I used a bench grinder with spiral bound buffs. The bench grinder must be mounted firmly to the bench. Never use the same buff for more than one type of compound. I use a stainless steel cutting compound and stainless coloring (finishing) compound available at many hardware stores. You can also order it online. Just get two spiral bound buffs and compounds made for stainless steel.
Use the cutting compound first by holding the stick to the buff while it's turning. This will load the buff with compound. Then hold the part to the buff surface so as to remove the 800 grit scratches you put in the piece. You don't have to use alot of pressure. Add more compound frequently. Run the buff up and down the piece until all the surface is shiny and you can't see any sanding scratches from any angle. Don't hold the buff too long in one spot or the stainless will turn blue. Also, be very careful and don't let the buff grab an edge. This will launch your part farther than you though possible narrowly missing you (hopefully) and destroying all your hard work.
Then switch buffs and repeat the process with the coloring compound. And, you're done!