Sand blasting to remove paint.
I have never tried chemical strippers to remove old paint from traffic signal parts. I have access to a sand blaster, so I use this method. I have some pictures here of a visor that I sand blasted.
Visors are thin aluminum and they warp under the pressure of sand blasting, as you can see in the pictures above. There is a way to fix this though and the same thing works for fixing dented and bent visors. As you see below, I put the visor around a piece of steel about the same diameter as the visor (any hard round object should work) and pound out the dents with a rubber hammer.
The picture below shows how I hang my signal parts from my garage door to paint them.
The method that I use to loosen frozen fasteners is heating them up with a propane torch like the one shown here.
Some traffic signal doors are held to their bodies with pins that are pressed into the mating fingers on the door and body as shown below.
This page was originally posted on 3/31/2002.
This is the sand blaster that I use. It is a metal cabinet with rubber gloves in the two access holes to protect your hands from the sand. A vacuum sucks up the dust created by the process. An air compressor shoots air through a hose and out the air gun. Another hose hooked up to the air gun leads to the bottom of the cabinet where it picks up sand from the pressure of the air traveling by the other end of the hose inside the air gun. Sand mixes with the air and shoots out the gun at high speed.
This is the visor after sand blasting the outside surface of it. All of the paint is removed in about 2 minutes or so. Sand blasting is fairly quick and clean when done inside a cabinet.
Sand blasting visors presents a problem though which brings me to my next tip...
Fixing dented visors.
Painting signal parts.
Frozen visor screws or other fasteners.
I put flame of the torch directly on the screw or on the immediate area that the screw is screwed into. After heating for about 30 seconds, you should be able to get the screw to turn. If it still resists a lot, try turning it half a turn counter-clockwise and then back clockwise a bit, then counter-clock wise again. Keep doing this until the screw turns freely enough that you are sure it will not break off. You should be prepared to repaint the signal though because heating up the paint will burn it, producing similar results to the picture below.
Please, if you are not an adult, get proper supervision. A propane torch is not a toy and can burn you or start a serious fire faster than you can say four way traffic signal.
Removing pins from door hinges.
Sometimes it is possible to use a small round object like a nail and hit it with a hammer to push the pin out of the hole, but this is risky. If the pin is tightly pressed into the hole, you could break the casting by using a hammer. The way I remove stubborn pins is by using a "pusher" like the one shown below.
This device is similar to a puller like what could be used to remove a steering wheel from a car, but it pushes the pin instead of pulling it. It is put over the two fingers that the pin is going through as shown below.
Once in position, the screw is turned clockwise so it tightens up the top piece against the nuts on the threaded rods on each end. Further turning starts to force the pin down through the hole it is in. A hole is in the bottom of the device to allow the pin to be pushed out the bottom finger on the signal. This method is almost sure to not break the casting because it presses the two fingers together against each other, preventing them from being bent in any way that would break them off. This is not a good tool to use where there are two fingers on one casting with a space between them like the picture below. If the pin is very tight, the two fingers will be bent and will probably break.