Will RP made for use with steel per aluminum or other metals?
No, it won’t hurt it. It’s not going to do any pitting or any corrosion, but you might notice a film on your parts. It is not going to do anything to provide your aluminum or your brass any protection.
Do I have to remove RP prior to phosphating?
You don’t necessarily have to remove the RP prior to phosphating, but it’s probably a good idea to eliminate contamination from getting into your phosphating tank or process, if you will. It is a good idea to incorporate some sort of cleaning stage prior to phosphating.
Will RP prevent flash rusting or cast-iron engine blocks?
Yes, absolutely. If you select the correct RP and you implement it in the right way, you can prevent flash rusting on your cast iron parts such as an engine block. You can do this in process.
Can I use the same cleaning and RP process for my cast aluminum parts
You can use the same cleaning process in some situations. Some chemicals might not be compatible with your aluminum, but when it comes to the RP, you’re going to need to apply an RP that you find for steel. Then you’re going need to apply a corrosion protection to the aluminum. You would need two separate RP stages if you were cleaning both aluminum and steel in your cleaning process.