Something just came up and I figured I should inform those that want to know the differences in chrome. Chrome basically comes in two types, hexavalent ( hex) and Trivalent (decorative). Hex chrome is the very, very hard functional old chrome that was used on bumpers wheels and trim through out the 40's, 50's and 60's and gained it's strength by being built up on the nickel sublayer to a reasonable thickness. thickness' of upto 0.000060" being common and occasionally 0.0001" being applied in high service areas. Due to it's hazards it is being phassed out and replaced by decorative trivalent chrome. This is normally 0.00001" to 0.00002" I plate mine thicker to around 0.000025" but it is darker because of it. Trivalent is the original chrome, but it cannot be built up as thick as the old hex chrome, and the color can vary from yellow, through gold, brown, blue, or like ours a murcury type color. Because it is not a strong trivalent fell by the wayside for many years, it is now the chrome of the era as hex slowly fades out, but trivalent has weaknesses you should be aware of. Trivalent chrome is salt based and has much less resistance to road salt than hex chrome which is acid based. Therefore trivalent is not really suitable for use on rims or areas subject to attack from road salt. It is great for use under the hood, on casings of summer rides and show pieces. Nearly all "Show chrome" is trivalent. Decorative hard chrome, a type of hex chrome for decorative applications is much better for bumpers and rims, though harder to find. It is worth seeking it out. These days for ultimate endurance bumpers and rims are best base plated with electroless nickel before bright nickel and chrome. Be aware, not all chrome is the same and some chromes can look quite different.
Lots of good things to know there. Some of it is a little beyond me, but I see what your saying. I've noticed some chrome looks great but tarneshes just getting wet. Other chrome can sit forever and look terrible and polish up great. I also noticed that some of Ford's chrome around 50-51 isn't too good. I guess the korean war made it hard to get good stuff for plating.
last year I bought a "rechromed" grille for my 51 chevy on ebay & within 3 days of installing it, it had all kinds of yellow stains & within 2 weeks it looked so bad I had to take it out. I even put a coat of wax on it before I installed it I then bought a nice used grille & it held up beautifully being outdoors for a year till I sold the car. Billy
The hex chrome used from the 30's through to the 80's will stand upto just about anything as long as the plating is continuous and the nickel has some depth. It is the nickel that gives the corrosion protection. The chrome is a layer that stops the nickel going yellowy gold. If you have yellow patches on your chrome it could be because of 1 of 3 things. 1) Chrome layer over the nickel is not continuous. This happens if the nickel becomes passive. This will polish out but return in hours. 2) Wax placed over the chrome is acidic and may be oxidizing or attacking the chrome. Hex chrome should never be waxed, it's unnecessary, while wax gives trivalent protection from salt. 3) Wax may have contained a solvent or acid that reacts with chrome. Chrome has little or no resistance to ammonia or sodium hydroxide, yet they are two additives used in 95% of chrome polishes.
Polisher, A quick question. No doubt you can answer it. Back in the '70s Black chrome was a big deal with show bikes. But it was real delacate. What was the deal with black chrome and is there a way to make it durable? Just curious.
Good stuff Polisher. If I can add some from a metallurgical perspective, is that any chrome plating is still a barrier type protection. In other words it keeps the water away from the steel. Like paint. As Polisher said, the nickel is really the main corrosion protection, the chrome is for appearance and looks. Any break in the coating causes the corrosion to start, and the steel actually corrodes to protect the plating. Zinc plating is sacrificial, in that it will corrode and protect the steel. That is why you see the white powder corrosion products on zinc plated parts. Old cadmium plating is same as zinc - sacrificial. The sacrificail aspect of zinc is why new cars use galvanized (zinc) steel for panels, with paint over the top. you get both barrier and sacrificial protection. Some terminology is also good here for prospective plating customers. Triple chrome means copper-nickel-chrome, not three layers of chrome. The copper smooths the steel surface, the nickel is for the corrosion, and very thin layer of chrome for looks.
Well, chrome should basically be washed with pure soap and towel dried. It shouldn't be waxed in especially in summer as the wax amplifies sun damage, and wax can make chrome look hazy. However sometimes surface marks need removing, or if near the ocean or salt roads with trivalent chrome it is worth using a waxed polish in winter. All new wheels are trivalent as the auto industry has a moritorium on hex chrome to keep DEP and EPA sweet. As for what type of polish, well I guess the English Custom Polishing range at www.englishcustompolishing.com is as good as you can get and better than most. They are endorsed by the most respected museums in the world. I own ECP so I must tell you I'm touting my own products here. There are other pH. neutral polishes out there, but no company offers quite an extensive range as ECP. So I at least feel I'm not acting out of Bias when I recommend them.
A lot of what was called "black chrome" back then was actually a carbon coating on top of stainless or regular chrome. It looked cool, but to get it right it became very brittle and would chip off very easily. Nowadays they can get the same effect with a coffee colored powder coat. Craig
Firstly let me explain that chrome is a superfine metallic clearcoat, it is the nickel underneath that gives chrome it's silvery lustre. Chrome is harder than any wax, putting a wax on it increases damage from sun, road grit and dust by amplifying the suns rays, guiding grit into the chrome causing more damage from pitting and making chrome hazy, and by creating a grinding paste of all sorts of grits on the surface. So always wash your chrome before you do anything to it. Hex chrome needs absolutely no protection other than washing and maybe a light polishing with ultrafine polish once a year. Trivalent chrome, however has much less resistance to salt and wax will help to protect it. That's why all the Beemer and mercedes wheels in the north east a flaking after 3 years. They are trivalent chrome and un-maintained and the salts the states are using now are MEAN. So using a pH neutral polish that has a protective wax is good on trivalent where there is salt. Using a quality polish can also salvage old hex chrome when it is beginning to break down, in that it will remove surface rusting that has got through the sublayers, return the nickel where it's exposed to bright and protect it from oxidizing by covering the exposed areas and blocking micro pores in the chrome. Now don't confuse pH neutral with pH balanced. a pH can be balanced to be alkali or acid. Neutral is neutral.
Well it was worth a shot. I been wonderin' about that stuff for a long time. HotRod thanks. Never could afford chrome anything back then. And always into drivers (riders?). Nevertheless I liked the look alot. I found some metalic black rattle can paint from Rustolium last fall that looks a lot like it, and it got me thinkin' and waitin' for a post abut chrome so I could ask one of my never ending dumb questions.
I was talking to a buddy of mine about a paint idea for my new ride. He mentioned that I could strip my chrome down to the copper layer and clear coat it to at to the copper I plan to paint the wheels. Can someone fill me in on this? Anyone done it? photos? I know chrome is a multi dipping process.
Thanks for the info Polisher. I have some chrome on my Stude that has some light scratches. It was done about 10 years ago, and is triple plated, from Toronto, Canada. I am going to try some of your stuff, and maybe I can salvage my abuse!-MIKE
Polisher... Do you know which type of chrome is on the "Chrome" piston rings? How about on the heavy equipment where theres a real heavy duty nasty looking chrome plating? Somebody told me what it was once apon a time... long since forgotten! Thanks!
That's good old fashioned industrial hex chrome. Just not polished underneath. But it's tough as hell and does good in friction areas because the micro-cracks in hexavalent trap oil. It's the same stuff used on fork tubes on bikes, but they polish the steel before they plate it. Beautiful when maxed out and tough as hell.
I can't tell you how many times I've read your posts about chrome and keeping it nice. Got a question... the chrome on Snap-On end wrenches etc... Is that the industrial chrome you speak of also? That stuff is indestructable. I want Snap-On to do all my chrome!
A plater once told me that chrome polish was only necessary if the chrome had been neglected for some time, that most of the time all that is necessary is to clean the chrome- you seem to echo this, however I'm thinking he was slightly off base with his chosen cleaner. You mentioned that trivalent has poor ammonia resistance- he told me to just use Windex to keep it clean. Yikes! Is the there a good/easy spray type cleaner that has no ammonia, that will work well? Should I just read the product labels at the grocery store?
Stripping chrome in stages is tricky. It's easy enough to remove the chrome with out removing the nickel as long as the part has no holes and cinsistant coverage. Removing the nickel with out removing the copper is tricky. It would probably need replating with copper to ensure a consistant coating. Then you have to polish and clear coat it in 1 hit. Any pores, cracks or microfissures in the clear and you'll have serious oxidization problems. Think I'd avoid that. Not a good idea. Unless you want it to oxidize. That could look pretty wild. Now copper coloured powder or ceramic coating. That's a different deal. Much more functional. Needs little maintenance. He mentioned that I could strip my chrome down to the copper layer and clear coat it to at to the copper I plan to paint the wheels. Can someone fill me in on this? Anyone done it? photos? I know chrome is a multi dipping process.[/QUOTE]
I guess I missed that one. I've never stripped bronze plating. To be honest I don't think I've ever seen bronze plate. It's a funky alloy to plate and would be very temperature and ampage sensitive. I wopuld think it's a bitch to strip it, probably would need a cyanide based bath to do it well, though I don't know. I've stripped plating off bronze to replate it that's easy enough and easy to work with for replating. I like plating brass and bronze, but the polishing dust makes everything taste funny no matter how well the respirator fits and how hard the dust extractors are working. That's not good, so It's probably as well I don't get too much of it.
Back in the days before cars came equipped with that decoartive film of plastic formerly known as a bumper, I can recall seeing the chrome on a bumper that was peeling. I'd estimate those flakes of peeling chrome were somewhere about .002/.003" or even more inches thick. I presume I'm either totally wrong (a common occurance with age) or, I was looking at not just the chrome but the nickel and other base plated metals. When someone says triple plated chrome, many of us think of copper, nickel and chrome. Are platers still doing it this or is most of this just sizzle and not much steak?
They used to pound the nickel on. Bumpers were never coppered, just plenty of nickel and then the chrome. The actual chrome tended to be thicker then too. Hex chrome could be built up thicker than modern decorative chrome. Now it's pretty much reserved for industrial use or gone to China, though there are a few shops left using Hexavalent, the DEP and EPA are all over them. They are becoming few and far between.
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