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Old 08-09-2020, 09:14 AM   #178
DeadheadNM
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Join Date: Dec 2010
Location: Eau Claire, WI
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Re: Build that 71 402 already

I seem to recall that zinc phosphate produced a glossy finish whereas manganese phosphate produced a flat, matte black finish. I believe the latter was typically used for GM fasteners etc. Is it possible your batches are a mix of zinc and manganese?
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