[Greg Reid]

Originally Posted by Entropy11

it’s just been time consuming and “experiments” to find what removes it the fastest without compromising the thickness of the panels.
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Do tell...
Been trying some different rust removal methods myself lately with mixed results. Interested in what you've come up with.

[Entropy11]

Originally Posted by Greg Reid

Do tell...
Been trying some different rust removal methods myself lately with mixed results. Interested in what you've come up with.

I’m big into SPI products so Ospho is my go-to.

I will say I’ve learned in the past that although phosphoric acid (key ingredient in Ospho or Milkstone Remover) is the safer or more “metal friendly” acid, if you trap a saturated paper towel below a layer of plastic wrap for several hours, it will begin eating its’ way down into the metal.

For this heavy scale stuff I usually blast the top of it with a 3M Bristle Brush to knock down what I can and then spray with Ospho while I hand sand it with either 80g if it’s heavy, down to a scotch-brite if it’s just rust trapped in pits.

For some reason I decided to wet-sand the rust (as mentioned above) with Sprayway glass cleaner instead of Ospho. I swear the rust removal was more substantial this way. At a minimum I’d say it was on par with the acid but far less of a safety concern compared to slinging acid around.

If you don’t knock the dark/black converted top of the scale rust off first then neither of the chemicals will perform as well. I’m addicted to the purple 36g 3M bristle brushes, also sold as the Scotch-Brite “Bodyman’s Bristle Disc”. They are pricey but they eat rust like crazy and are very gentle on the good steel below. They do practically last forever if you treat them well though. The other grades of their bristle discs are not agressive enough and neither are any knock-off ones on Amazon I’ve ever tried. There’s also a night/day difference between running them on a drill with a roloc adapter vs an angle die grinder at 10-15K rpm’s.