There are a few different methods of doing this depending on how good of a job you want to do how much time and energy you have and how large of an area you are doing.
Repainting galvanized siding.
Once dry remove the plastic sheeting and masking tape.
Step 1 clean the steel siding.
The first step includes cleaning.
Apply the acrylic paint to the wall on top of the primer in the same way you applied the primer to the metal siding.
The vinegar is a mild acid which acts to etch the galvanized coating so the paint will stick.
Paint applied over this oily surface or clear passivator will peel quickly.
Things you ll need chemical degreaser distilled white vinegar lint free cloth high grit sandpaper or wire brush exterior latex primer exterior latex paint paintbrush or roller rubber gloves.
Go over the metal with a wire brush to remove any oxidation.
This will help clean away all the dirt that accumulates on the steel siding.
The best cordless vacuum for pet hair.
Prime the surface with a primer made for metal.
Wash the steel siding with trisodium phosphate tsp and use a pressure washer to rinse thoroughly.
Wait for this layer of paint to dry and then apply a second coat.
If you are striping a small area then you can do very well with a bucket of water that has some bleach and tsp in it.