Restoring 14" wheels [1/3]
I got four 14 inch alloy wheels with a car I bought and their appearance was pretty bad. There were several dents and paint was come loose because of oxidation. I already had some sets of 15 inch alloys for summer use so I decided to restore these 14 inch wheels for snow tyres. The goal was to remove old layers of paint, sand blast them with fine sand and finally paint them with proper chemicals. I was not after a surface smooth as a mirror which would have required hours of more work. Anyway these wheels weren't worth of the extra trouble. Later I discovered that one of the wheels was quite bent and even after balancing it shakes a bit... The lesson of this is that before doing any work you should check the wheels with a balancing machine in a tyre shop in case they are too warped.
As you can see the wheels were in a bad state. The surface under the paint had become oxidized in many places and the paint was ready to peel off.
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You can try to use different kinds of mechanical ways (grinding machines etc) to remove the old paint but it can be very frustating and time consuming especially if the wheels have several thick and durable layers of paint like these wheels. And there are always some areas you can't touch with the grinder. I also tried sand blasting the old paint but it was too hard.
You can also spend as much time you like grinding the surface with different grades of sandpaper to get very smooth and shiny surface...
However, usually the easiest way to remove old paint is to use some paint stripping agent. It doesn't take too long before the old paint is practically peeling off. You may have apply the paint remover several times to get rid of the paint but after that it's rather easy to brush it off with a wire brush and water. You can see how in some areas the surface below the paint has oxidized while some areas still have the smooth untouched surface.
After removing the old paint I sand blasted the wheels with very fine sand to avoid pits. This took quite long time because there was still some obsessive spots of paint... You can speed up the process by using higher pressure, heavy-duty blasting equipment and coarser grained sand but then you also get rougher surface as a result.