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My poor 66' Toronado's bumper is in a bit of rough shape. On the chrome side, it actually looks pretty good. I mean, it's not show quality, but it's acceptable for me. The inner side, however, is pretty rough and I'd like to do something about that to hopefully slow down the deterioration. Just wanted to run my plan down by the experts, all feedback is welcome.
I was just going to hit the inside with a grinder and get rid of as much rust and peeling chrome as possible. Then I was going to hit it with phosphoric acid, degrease, and paint it with some leftover silver POR15 paint I have. Just wondering if this will work ok on this thing or will it just be pointless? See my pictures below. Thanks!
You can do all that grinding and degreasing, but, if it were me, I wouldn't go through that much trouble. Since the back side of the bumper is never seen, all you really need to do is paint over it with something like POR-15. That stuff is designed to painted right over rust to prevent further rust. You might do some sanding to get rid of the loose rust, but that's about as much as I would do. No for need for degreasers or acid baths or whatever, unless the POR-15 instructions say to do so. I would just do whatever the POR-15 instructions say to do as far as surface preparation, do it, paint it, and be done.
You can do all that grinding and degreasing, but, if it were me, I wouldn't go through that much trouble. Since the back side of the bumper is never seen, all you really need to do is paint over it with something like POR-15. That stuff is designed to painted right over rust to prevent further rust. You might do some sanding to get rid of the loose rust, but that's about as much as I would do. No for need for degreasers or acid baths or whatever, unless the POR-15 instructions say to do so. I would just do whatever the POR-15 instructions say to do as far as surface preparation, do it, paint it, and be done.
Yeah, POR15 does require the metal prep though (which is phosphoric acid). Same with the degreaser. It's a three step process, as posted above.
Yeah, POR15 does require the metal prep though (which is phosphoric acid). Same with the degreaser. It's a three step process, as posted above.
I thought your original post was spot-on in terms of prep work. I would neutralize current rust by removing current rust w/ H3PO4 (phosphoric acid). The "rate" at which the Rxn occurs is dependent on the H3PO4 concentration. POR15 Metal Prep is a 10% (w/w) H3PO3 solution. You can easily make your own (I'm sure you know this) for far fewer green backs and you can increase the concentration since consumer grade H3PO4 is available in 85% (w/w) solutions.
Almost forgot. You should neutralize the phosphoric acid, whatever % you elect to use. You only need to continuously bathe the bumper with water for say one minute after you're done w/ the H3PO4; but, give the bumper a thorough water bath to remove the H3PO4. At any time you feel the Rxn is getting away from you and continues to etch past the removal/neutralization of the rust, you can make a simple 10% solution of Borax, or Baking Soda, etc. any weak base solution will neutralize any remnants of H3PO4 remaining on the bumper. IOW, any of those will stop the Rxn.
Almost forgot. You should neutralize the phosphoric acid, whatever % you elect to use. You only need to continuously bathe the bumper with water for say one minute after you're done w/ the H3PO4; but, give the bumper a thorough water bath to remove the H3PO4. At any time you feel the Rxn is getting away from you and continues to etch past the removal/neutralization of the rust, you can make a simple 10% solution of Borax, or Baking Soda, etc. any weak base solution will neutralize any remnants of H3PO4 remaining on the bumper. IOW, any of those will stop the Rxn.
Thx Norm. Yeah, up here in Canada it's pretty much impossible to find straight phosphoric acid for whatever reason. The highest concentration stuff I've been able to find is the Krud Kutter "must for rust" stuff so that's what I've been buying rather than the weaker POR branded stuff. Seems to be working out alright.
I've been keeping my eyes open for a cheaper solution but I've not come across it yet.
I'll finish this up & grab a cookie on my way out the door. Note the above POR15 Metal Prep solution contains 1.0% (w/w) ethoxylated alcohol. An ethoxylated alcohol is also known as a surfactant. A surfactant has BOTH a water-hating side (of the molecule) and a water-loving side (of the molecule) and they readily dissolve grease - not surprising then they use it in POR15 Metal Prep. But guess what, the most active constituents of any Simple Green product is composed of surfactants (ethoxylated alcohols). Therefore, save yourself more green back and simply use Simple Green as your degreaser.
Yeah, up here in Canada it's pretty much impossible to find straight phosphoric acid for whatever reason. The highest concentration stuff I've been able to find is the Krud Kutter "must for rust" stuff so that's what I've been buying rather than the weaker POR branded stuff. Seems to be working out alright.
I've been keeping my eyes open for a cheaper solution but I've not come across it yet.
Krud Kutter "Must For Rust" should work fine.
You should be able to get Klean Strip Concrete and Metal Prep in any of your big box home department stores (either in the paint department or concrete/mortar department), as well.
You should be able to get Klean Strip Concrete and Metal Prep in any of your big box home department stores (either in the paint department or concrete/mortar department), as well.
Try the Canadian websites for Home Depot (just put a .ca instead of a .com), etc. You won't find any of that stuff available anywhere. There must be some kind of regulation here that they don't have south of the border because you simply won't find that stuff off the shelf anywhere, yet it seems easily obtainable in the US.
Our big home improvment places are Home Depot, Kent, RONA, and Home Hardware. None of them sell the stuff.
Try the Canadian websites for Home Depot (just put a .ca instead of a .com), etc. You won't find any of that stuff available anywhere. There must be some kind of regulation here that they don't have south of the border because you simply won't find that stuff off the shelf anywhere, yet it seems easily obtainable in the US.
Our big home improvment places are Home Depot, Kent, RONA, and Home Hardware. None of them sell the stuff.
Nothing will stop the #1 consumer capitalist country of the world....
November 5th, 2023, 08:48 AM
