(Tom--the thread morphed too much. Time for a new topic.)
Hi Tom,
(We'll be in touch on the plating issue.)
Further to that, understand (most people in the marine industry know this) that
zinc plating and the related galvanizing are "sacrificial" coatings specifically designed to wear away. Nearly all boats have a "sacrifical anode" on them so that the seawater (and lake water too) attacks the easy stuff; that's zinc and magnesium before the steel gets attacked.
The sacrifical part needs to wear away completely before the steel gets attacked. The outdrive on my boat, which is powder-coated cast aluminum, still has one of these anodes on it since the zinc or magnesium is more active than aluminum and steel and will corrode away before the steel and aluminum parts on the boat. Many steel towers, such as those for power lines, cell phones, etc. are also experimenting with buried sacrifical anodes to get longer life. (Just wait, soon we'll see the price of zinc and magnesium skyrocket due to unprecedented demand in China...)
There are two good reasons to choose only
cadmium plating for parts on our cars: first, we often try to emulate what was originally done. Well, what was originally done was cadmium, not zinc. Second, read the following from BNET:
Cadmium plating has many outstanding qualities that have been difficult to duplicate, the most important being high corrosion resistance. Contrary to the hype, cadmium plating is still easily available and is safely applied by platers. Zinc alloys were developed to provide alternatives to cadmium plating. The zinc alloys all have many excellent features, but none of them seems to be a perfect replacement for cadmium plating.Cadmium no doubt is poisonous and toxic, but it isn't sacrificial in the same sense as zinc; it will wear away over time but is better than zinc. Works for me! In an MBCA Concours, if one is concerned about that, the expert judges can tell zinc from cadmium plating. It's a different color. But you can see that for yourself!
While some corrosives (either low pH acids or hi pH caustics) can attack plated parts--acids in particular will eat a zinc coating in a heartbeat--most cleaners one could use in their engine bay are not that hi or lo in pH to make that much of an effect. I don't know of any real reason to use a lo pH cleaning compound in an engine bay, but most detergents or cleaners of any type--save for those with neutral pH--are hi pH. Just like most soaps and shampoos. If it isn't eating away at your skin it isn't going to eat metal, particularly in the real-world method of cleaning via dampened rag or short sprays followed by rinsing or wiping. Simple rule of thumb.
You had asked about what I use, and the preferred compound for me, for degreasing is an "organic solvent" a/k/a just plain old mineral spirits on metal parts, and that "oil eater"
http://www.oileater.com/ on non-metallic parts. The oil eater is water based so I prefer NOT to use that on metal. Organic solvents have absolutely no affect on plated surfaces, and don't affect automotive painted surfaces much either (think bug and tar remover).
I prefer mineral spirits to industrial degreasers (think trichlorethylene) or brake cleaner (methanol, toluene and acetone blends) which most certainly affect painted surfaces and most plastics. But make no mistake: I use these serious degreasers when necessary. I don't spray them willy-nilly everywhere, though. I had some very serious dirt and grease build-up on my bicycle's gear cog last week, and scrubbing with a brush and mineral spirits didn't help too much. Blasting with a can of trichlorethylene did. (CRC Industrial Degreaser
http://www.crcindustries.com/auto/content/products.aspx Note they make a whole line of industrial cleaners and most are available at Grainger)
Speaking of cleaning, I had a crack in a stainless steel water tank at my car wash. I removed it and had the crack repaired. Before I put it back, I decided to clean up the tank a bit--I tried all kinds of my cleaners, none did a particularly good job. I tried a wire brush on my drill--while the SS was brushed in the first place, it didn't do as good a job of removing hard-water crust and staining as one might expect...then I pulled out the
strong stuff: aluminum brightener/wall cleaner.
A horrifically dangerous brew of hydroflouric; hydrochloric, and sulfuric acids. Mixed up a dilute batch, sprayed it on. Let it sit for a few minutes, neutralized it with hi-pH detergent and then hosed it all off. My goodness--this 18-year old tank looked
absolutely brand-spanking new! Not only clean, but very bright as well. If I ever have my valve cover off, it will get the same treatment and you can be sure it will look exactly as it popped out of the mold after casting!
I like looking at the Eastwood Catalog, and Griot's Garage as well as anyone, but cleaning methods and compounds and been around a lot longer than these guys have.
My own opinion is that
some of the things they sell are overpriced and appeal as much to emotion as science.
While one can certainly feel "safe" washing their car (for those that choose to use soap and water the old fashioned way) with one of Griot's $39.99/gallon+shipping car wash detergents, I'm not convinced this is any better than high quality products such as those from Zymol, Turtle Wax, Eagle One, and others one can get locally at any auto parts store for a lot less money. You are just removing dirt, for goodness sake! In scientific terms, you have surfactants, detergent builders, etc, formulated for the type of "dirt" being removed and the type of surface being cleaned, and thus the biggest difference between them are fragrance, color, thickness, foaming action, etc. "Inactive ingredients".
For example, most hi pH products contain a dilute caustic--some use sodium hydroxide, others potassium. Most lo-pH products contain a dilute acid--most choose phosphoric, but others contain hydrochloric or glycolic. There are buffering agents, too: some contain sodium carbonate, others a potassium salt.
They all provide mostly similar actions, thus most car wash soaps commercial or otherwise are
basically the same since they are devised and formulated to remove the same kinds of dirt from the same kinds of surfaces. Just as P&G figured out how to appeal to "housewives" with differentiation of laundry detergent (Mountain Fresh! All-Temperature! Now with Bleach Alternative!), some manufacturers have figured out how to appeal to collectible car owners with their products.
The best kind of car wash detergent could be formulated to be basically odorless, colorless and have no foaming action at all.
Those are all added for customer appeal. The bad converse of that, is you can make a really poor car wash detergent that has lots of foam, looks real thick, smells great, and has a great color, but doesn't do diddly. A bunch of inactive ingredients that many think are what's at work. If you don't respect my opinion, that's OK--this is from the chemists at my two main chemical suppliers, Warsaw Chemical and Stone Soap.
If you want to really get your car clean, try the clay bar after you are convinced that the surface is as thoroughly clean as you can get it. The clay bar (a mainstay of detailers) really gets all the ground in crud out of the paint surface and is really perfect for prep prior to a waxing. Wax protects your paint like plating protects your steel.
Griot's paint clay and lube kit is about twice the price of your local auto parts store. You be the judge if the Griot's product is worth the extra money.
My engine bay is generally accepted as nice; after 10,000 miles and 8 years, it doesn't look exactly the same as it did when it came back from the restorer and with each passing mile it becomes a bit harder to maintain. There was a film made by MB-USA back in the 1978 where they discussed the restoration of the only remaining Steinway [Piano] made USA-built Mercedes, and they had a notable quote: once a restored car gets any time outside; being driven; or on the road, the restoration becomes a de-restoration. And as time goes on, it is harder and harder to maintain.
