Interesting! I hadn't known about a product that can blacken old bolts. I need to try it out.Rather than painting the coin door bolt heads, I decided to re-do the black oxide coating. This creates a "light black" matte finish, if there is such a thing. Here's what I started with. (The one with the tape is not original, and had to be cut to length.)
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After cutting the one replacement bolt, I needed to remove the letters on the head. I added a nut and ran it against abrasive with a drill. First 120 grit, then a sanding block to smooth it out.
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Then I removed the head finish from the rest of the bolts with a wire wheel.
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Now I mixed up the black oxide concentrate with water and dropped the bolts in for 6 minutes.
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I used the cotton swab to stir and get bubbles off.
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Afterward, rinse with water.
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Then coat with penetrating oil and rub clean.
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And... PRESTO! Black bolts.
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I'm assuming this is a similar one on Amazon:
Thanks for the tip!
Del



























