Acid deneutralizing

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PostPosted: Mon Jun 29, 2015 6:05 pm
I sprayed some Must for Rust(Phosphoric Acid) on a few blasted panels that were flash rusting to protect while I did some work.
After finishing work I now want to epoxy primer car. What is the best way to get the Phosphoric Acid off panels so it will not effect epoxy.

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PostPosted: Mon Jun 29, 2015 9:25 pm
Apply more phosphoric acid and then before it dries scrub with soap (dawn) and water with a red Scotchbrite. Suds it up and scrub it real good and then rinse with fresh water and blow dry with compressed air paying close attention to seams and pocket areas.
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ACTS 16:31



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PostPosted: Tue Jun 30, 2015 6:50 pm
Does it deactivate easily with soap/water and scuff pad or would it be quicker to just quickly/lightly sandblast it off?

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PostPosted: Tue Jun 30, 2015 10:13 pm
In this case neutralizing is taking an acidic solution (a PH of 1 - 6) and adding a basic solution (a Ph of 8 - 10) to arrive at a neutral solution of PH 7.

Dawn Ultra Concentrated Dish Washing liquid has a pH of 9.

The Phosphoric acid on your car is at best 45% acid and has a PH around 2 - 3 so applying the dish soap neutralizes the acid.
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PostPosted: Tue Jun 30, 2015 10:20 pm
You need to add an alkaline solution (such as soap) to neutralize the
phosphoric acid in the MustForRust. Sandblasting will remove the surface
residue but the underlying metal will still be acidic.

68Coronet's method is a good one. TSP(TriSodium Phosphate) is also good
as a neutralizer.
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PostPosted: Wed Jul 01, 2015 5:05 am
'68 Coronet R/T wrote:In this case neutralizing is taking an acidic solution (a PH of 1 - 6) and adding a basic solution (a Ph of 8 - 10) to arrive at a neutral solution of PH 7.

Dawn Ultra Concentrated Dish Washing liquid has a pH of 9.

The Phosphoric acid on your car is at best 45% acid and has a PH around 2 - 3 so applying the dish soap neutralizes the acid.


Would it work to rewet with acid and pressure wash it off with diluted dawn soap siphoned in through pressure washer or would that not get deep enough?
Panels are all interior/engine bay so worried it may be to tough to get into seams.

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PostPosted: Wed Jul 01, 2015 10:18 am
Wouldn't know personally because I have never tried it. I find that when I scrub something by hand I pay more attention to details.
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