Copper may corrode in contact with aluminum.
That's one reason why aluminum wiring was problematic. People often spliced copper wire to it. Corrosion at the joint produced resistance which started fires....
Where were you when I bought my first home!?!
The previous owners re-wired the kitchen in the 1970's. There were scorch marks above the electrical outlets in that part of the house. I just surrendered and had all of that aluminum wiring removed and replaced with pure copper. Did not want to die in a house fire due to corrosion of dissimilar metals in contact at a splice.
phew
This is relevant to our threaded steel fasteners-in-aluminum discussion. Dissimilar metals placed together at a physical contact point can corrode where any sort of moisture could be present, even via humidity. Generic steel fasteners are a great choice for strength and durability, but
they will cause corrosion when used to fasten alloys commonly used in constructing an aluminum engine. The threads can seize, making fastener removal impossible. I had to ask my friends who fix airplanes to gain a little knowledge on that. So, now I know why all of those Honda fasteners have that silver-gold sheen to them. The electroplate is durable with good surface hardness, and is perfect for multiple-time use on our vehicles with aluminum stuff to be fastened.
Something else I learned: many times, these fasteners, when used in critical aero applications, are
one-time use. Once threaded in and any torque applied, if removed, they have to be discarded and a new fastener installed.
Agree. Washers are cheap. You can probably get 100 of them for less than $10.
Don’t forget to buy new fill plug washers too.
I have no idea why Honda charges sooooooo much for these. Commercialy pure aluminum is less expensive than high-strength alloys, and is really malleable, perfect for a crush washer. You have to use engineered alloys to get the strength we need for blocks, heads, wing spars, skateboards, etc. A crush washer has to be pretty close to pure aluminum to allow itself to be extruded like that when we apply light torque to that drain bolt, ergo, not very expensive aluminum.
I got a hundred of them online, years ago, for the oil drain pan, and a slightly smaller number for the ATF plug. I'll bet it's not even "beer can aluminum" (which is probably a pretty strong alloy), but just plain commercially pure aluminum. Shouldn't cost $8.00 per each!
Out of curiosity, this morning I grabbed a previously-used ATF plug crush washer that was sitting on my desk and tapped it on an anvil with a regular claw hammer. Was able to almost turn it into a circle of thin foil with very little effort. It did start to work harden as I approached about 1/64" of thickness.
After cleaning the bolt head, putting corrosion inhibitor on it, buying a pack of washers, and torquing it properly, Drain'n'Fills are really easy now.
As long as the electroplate on the plug's threads are in good shape, you're going to be golden (both you and the plug...didn't intend a pun, it just came out that way).
I've seen these shiny fasteners since the 1970's. Had no idea why they had that electroplate on them. Now I know.
OF
