[SEL] Anyone Ever Used Phosphoric Acid to DeRust

[Steve W.]

Paul Maples wrote:
> Folks I was wondering if anyone had used phosphoric acid to derust? I have some phosphoric acid and was thinking of using it in the bottom of my Stover Block (base) where the oil sump is. Over the years water had condensed in this area and there is a pretty good rust area for about 2" on the inside of the crankcase.
> 
> If anyone has used Phosphoric Acid I would like to know what strength you used, did you cut it with water, about how long did you leave it on the metal and what did you neutralize it with.
> 
> Thanks,
> 
> Paul
> 
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> 

Yep, Navel Jelly is Phosphoric acid made into a gel. The stuff used in 
many body shops as a rust neutralizer is also Phosphoric acid reduced 
down with water. Metal-Prep 79 is what I use in the shop as a panel prep 
to prevent light rust when working with bare metal. It is 95% Phosphoric 
acid with a couple other chemicals.

On heavy rust it gets diluted very little (1 pint of water to one gallon 
of acid) with water. Light overnight rust gets a spritz with the bottle 
of a reverse mix. Then wiped off and dried.
Immersion bath gets 1 quart MP79 to  3 quarts water.

-- 
Steve W.
Near Cooperstown, New York