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I like to think of rust as malignate cancer. It is almost akin to a living organism feeding on the metal and accelerated by moisture.
If you remove any rust that may come loose later, then sand to a solid structure, then treat you may stop it coming back for many years or at all.
If you leave / don't remove the excess flakes and it is still getting moisture, then it will come back, it may brood under the surface for a while until it recieves enough moisture to accelerate the bloom.
I have left oranage surface rust then threated it with phosphoric acid, sold as "rust converter" in home DiY stores. It hasn't bloomed again in several years, yet would if it was still getting moisture from somewhere.
The trick is to eliminate the accelerator which is water / moisture.
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