06-16-2008, 07:53 PM
"The black is exactly what the muriatic acid is supposed to do. That is the black iron oxide that is desired since it does not attract water like red iron oxide will."
Uh.. no. the black crud left in the pits is a mix of iron rust, iron particles, carbon and other insolubles from the steel. Also contains chloride, a very bad actor towards future corrosion problems. Best not to use muriatic acid AT ALL to strip chasis, phosphoric acid (Naval Jelly, etc. type de-rusters) produces an iron phosphate type film that inhibits future corrosion and makes for an excellent post paint base after rinsing.
As for cleaning up the muriatic stripped chasis, you need to neutralize the surface with bicarb soln. (Baking Soda) and rinse well. Otherwise, a few years down the road, those "black oxide pits" will come back to haunt you...
From an electrochemist who's been in the industry for 40+ years.
John L.
Uh.. no. the black crud left in the pits is a mix of iron rust, iron particles, carbon and other insolubles from the steel. Also contains chloride, a very bad actor towards future corrosion problems. Best not to use muriatic acid AT ALL to strip chasis, phosphoric acid (Naval Jelly, etc. type de-rusters) produces an iron phosphate type film that inhibits future corrosion and makes for an excellent post paint base after rinsing.
As for cleaning up the muriatic stripped chasis, you need to neutralize the surface with bicarb soln. (Baking Soda) and rinse well. Otherwise, a few years down the road, those "black oxide pits" will come back to haunt you...
From an electrochemist who's been in the industry for 40+ years.
John L.
