What is correct acid to stop flash rust?

Discussion in 'Color is everything!' started by copperheadgs1, May 21, 2008.

  1. Aerobatix

    Aerobatix Well-Known Member

    I bought a gallon of the OSPHO product. It seems to work well but I am new to using these types of products.

    What happens to the bare metal that has been treated by using OSPHO or some other phosphoric acid product if you simply apply the acid and leave the metal alone (do not rinse, clean or prime/paint)?

    Does the acid wash process provide some long term/permanent coating to the metal, thus reducing the need to paint?

    Curious about applying the acid wash to metal in areas that will not be easily accessible to apply paint? Will the acid wash stop/convert the rust and then also leave some type of phosphate coating to protect the metal long term?

  2. DaWildcat

    DaWildcat Platinum Level Contributor

    I've never relied on the use of "rust converters". It's too difficult to control residual acidity, and you never really know if you "got it all". I guess they have their place for structural repairs & such rather than surfaces that are supposed to be finished for appearance.

    All my permanent repairs consist of chemical dipping and an epoxy primer bath afterwards. On Tuesday I took a hood out of storage that only got to the epoxy primer stage 18 years ago, and it's as good as the day I put it away.

    Here's the lowdown on how the converters work, in a nutshell:


  3. gbsean

    gbsean Moderator

    agree an epoxy primer actually provides an air tight seal on all areas that it is applied to...many top name restoration shops use Epoxy Primers as the provide the best corrosion protection...2k primers are still porous and unless they are painted immediately are prone to rustings..most restoration shops apply an Epoxy to seal the metal and apply a 2k on top for filling......you can even apply body filler ontop of Epoxy

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