On Thu, 19 Oct 2017 08:17:50 -0500, "Paul K. Dickman"
wrote:


"Arjun Sharma" wrote in message
...
On Wednesday, October 18, 2017 at 6:44:04 AM UTC-5, Arjun Sharma wrote:
Hi there. I bought a bunch of big aluminum screws to help secure an
aluminum pergola I'm building
(https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1)

I'd like to remove the zinc plating to reduce galvanic corrosion (I'll
probably anodize the screws). I Googled it and found a couple tutorials
around using citric acid and another using another type of acid. However,
when I went to the hardware store, they had nothing of the sort.

Any suggestions for the best way to go about this (or where to get a
strong enough acid) ? Thanks!

Thanks for the input, everyone.

Any idea what people use, then? I know pergolas (and other structures) made
from aluminum are quite common. Surely they have some mechanism for
attaching the aluminum to the ground, wall, or in my case parapet wall.

I don't mind just using these screws, assuming they're zinc-plated steel. I
just was worried about galvanic corrosion over time.

You could electrically isolate the bolts by using a plastic sleeve and
washer to keep the steel screw from actually touching the aluminum.

Right. Unless you isolate them like that, either the fastener or the
abluminum being fastened is going to corrode eventually. In the case
of common steel fasteners, they'll corrode first -- and it's generally
simple oxidation of the steel, not galvanic corrosion in the presence
of aluminum in a galvanic "cell." Theoretically, the aluminum should
protect the steel but it usually does not.

Google "fasteners for aluminum" and read a few of the explanations.
You'll see what's used in industry, and why, with plenty of examples.

--
Ed Huntress