Step 1 clean the steel siding.
Painting steel house siding.
When this happens the metal is exposed to the elements and will start to eventually rust.
Wash the steel siding with trisodium phosphate tsp and use a pressure washer to rinse thoroughly.
Depends on the weather but three or four or five hours is not unusual.
Paint the steel siding panels using the sprayer.
This is followed by fading and thinning of the color.
But i would use the oil based rust oleum primer which by the way takes forever to dry.
For steel use a latex bonding primer instead of a regular metal paint primer.
Cleaning of the surface can be done by hand washing with warm soapy water or with the use of a high pressure washer 2500 psi minimum.
Begin by thoroughly cleaning your siding of all loose dirt chalk and other contaminants.
Start at the top of the wall and across the length of the metal siding.
Aim the sprayer nozzle directly at the panels eight inches from the siding surface.
Do this as soon as any spots start to show the steel underneath or do it a little sooner if you are trying to sell your house.
This will help clean away all the dirt that accumulates on the steel siding.
That is how you can get the paint to adhere to steel siding.
As with all exterior painting projects proper surface preparation is the key to restoring your metal siding.
When ready pour the primer into the paint container on the sprayer or pour the primer into the paint tray.
Since any of this is clearly bad for your metal siding it is vital that you re paint your metal siding.
Then apply the primer to the metal siding in even strokes.
It also helps to peel away the previous paint on the steel siding leaving it neat and clean.
And then i would use the rust oleum top coat.