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What is "pre-dip blackener" made of?

Hi, several companies make a "Pre-dip blackener" used in the firearms industry to give a "black" finish to Manganese Phosphate coated weapons.

I know a few companies sell this product (Mount labs', Brownells [affil links]). But what exactly is this stuff?

You dip the long arm in the pre-dip blackener solution then into your phosphate bath for processing. The result is a truly "black" phosphate coating that won't come off as opposed to the charcoal to dark grey we normally see.

What exactly is this stuff? Antimony Trichloride?

What?

Any help is appreciated. -Russ

R.B. Rogers
- Tampa, Florida USA
2000

Russ - Manganese (and zinc) phosphate blackening pre-dips are an acidic antimony compound. Some are better than others for color consistency.

Dan Brewer
chemical process supplier - Gurnee, Illinois
2000

Does the Tenifer finish of Glocks pose a problem for getting a good even finish with the pre-dip blackener and phosphate finishes? Is it necessary to strip the existing phosphate off prior to refinishing? Could scratches to an existing phosphate finish be touched up with pre-dip blackener and the phosphate finish or is it necessary to totally refinish for a good match?

marty
- melbourne, florida
2000

Ed. note: full name next time, please, Marty.

Tenifer is a proprietary process that is similar to QPQ or Melonite. I do not believe you can phosphate this already plated part, but would have to strip it. Its not an easy coating to remove, due to its high surface hardness.

Jeff O'Brien
- Tucson, Arizona
August 10, 2009