Grade 8 nuts and bolts; yellow zinc finish; when did this become the norm?

[Gary B.]

I searched the archives but didn't find the answer to a question I have. But maybe I missed it. These days most grade 8 nuts and bolts you buy at the hardware store are yellowish/copperish/goldish in color. But I don't think that finish was typical for grade 8, C2-era nuts and bolts. I'm finding some of the reproduction parts companies, like Dr. Rebuild and LIC, are supplying some repro bolts and nuts that are yellow zinc. That finish stands out like a sore thumb. Also, I don't see any mention of yellow zinc nuts and bolts in the '66 TIM&JG. Are there any examples of grade 8 nuts or bolts on C2-ere cars that were originally yellow zinc? Or was the yellow zinc plating something that became the standard finish for grade 8 nuts more recently than the 1960s?

Thanks,

Gary

[Joe L.]

Re: Grade 8 nuts and bolts; yellow zinc finish; when did this become the norm?

I searched the archives but didn't find the answer to a question I have. But maybe I missed it. These days most grade 8 nuts and bolts you buy at the hardware store are yellowish/copperish/goldish in color. But I don't think that finish was typical for grade 8, C2-era nuts and bolts. I'm finding some of the reproduction parts companies, like Dr. Rebuild and LIC, are supplying some repro bolts and nuts that are yellow zinc. That finish stands out like a sore thumb. Also, I don't see any mention of yellow zinc nuts and bolts in the '66 TIM&JG. Are there any examples of grade 8 nuts or bolts on C2-ere cars that were originally yellow zinc? Or was the yellow zinc plating something that became the standard finish for grade 8 nuts more recently than the 1960s?

Thanks,

Gary

Gary------


I don't know when the practice started but it's been around for a long time although certainly not in the C1 or C2 era. Probably not for most, if not all, of the C3 era, either. For the most part, grade 8 fasteners during the C1-C3 era were not even cadmium or zinc plated----they were mostly natural or black phosphate finished. Some were zinc or cadmium finished, though.

The "gold" color of zinc or cadmium plated fasteners (actually, almost exclusively zinc for the last 50+ years) is done to provide extra corrosion protection AND help identify them as grade 8. The color is imparted by a chromate-based "over-plate". If it bothers one, it is easily removed. Just immerse the part in a dilute acid solution until the color is gone. Less than a minute should do the trick. Be careful, though, as one does not want to remove the zinc. As soon as the color is gone, remove the fastener from the solution and rinse well with water.