[Planet_Lover]

Recently I've become interested in potentially getting into Copper, Nickle, and Chrome plating of steel auto parts.  My main interest is in restoration of antique cars.   The cost of having parts plated is formidable, and so I was looking into the possibility of starting up my own plating shop.  Doing research quickly reveals why it is so costly.  And the main cost appears to be associated with the extreme toxicity of the chemical baths used when electroplating these metals.

My question to the chemistry community is to ask why it is necessary to use such toxic bath chemicals?  I'm not a chemist, but it would seem to be that in this 21st century with modern chemical knowledge someone would have figured out a less toxic way to electroplate (or create) a very high-gloss metallic finish. 

What is it about the electroplating process of these metals that requires that such toxic baths?  It would seem to me that chemists should be able to find a less toxic way of electroplating metals.

Can someone explain the reason why such toxic solutions are required to facilitate the electroplating of these metals?  And why it is that no other chemical solutions are possible?

Thank you.

[chenbeier]

The reason is, that most all transition metalls in ionic form are toxic. This cannot be changed. If you want plate chromium for example you need chromic acid for instants and this is toxic. The same for Nickel, etc.

[Planet_Lover]

Is there any way to recycle chrome?

Let's say I have a lot of chrome car parts that I don't care about.  Is it possible to place these in a tank and us them as anodes (or cathodes) whatever polarity is required.  And strip the chrome from those parts electrically and transfer it over to the parts I want to re-chrome?

I'm not exactly inexperienced with electroplating.  Years ago I used to work at a job where I was silver-plating.  I don't recall the chemicals we used.  But I do recall that we could strip the silver back off the parts by reversing the current.

We were silver plating electrical parts for a manufacturer of electric stoves.   The silver plated parts were used as electrical connectors.

In any case I vividly recall that on occasion the silver plating process went wrong and the parts came out silver plated, but looked horrible cosmetically.  I was told that they would still work well for the intended purpose, but they couldn't sell ugly looking parts to the consumer.   So we had to strip the silver back off, and re-plate them.   I found that quite interesting because after striping the silver back off, the original steel parts looked exactly as they did before plating them.  Also the silver anodes got bigger again (i.e. the silver really did return to the source anodes)

So I'm wondering if something similar can be done with chrome?

Can I take an unwanted chrome car bumper (for example), electrically strip the chrome from it, and then re-plate that same chrome back onto another bumper?   And what kind of chemical baths would I need to do that?

It just seems to me that there must be some way to get around the toxicity of the bath solution during this process.

If the chrome itself is the toxin, then if it goes from one metal part over to another, why should the bath solution become toxic?  The chrome itself should be on the metal parts, not in the bath water?  Except for the brief time during the actual transfer process.

[chenbeier]

Every plated metal can be stripped, but it is not working elctrical but its working chemical. The chrome is dissolved in an acid and can be gained back from there. The problem is, the car bumper is not only chromium. It is a steel part and probably plated first with copper or nickel before getting the final layer of chromium. So you will have a mixture of different metals.

[Borek]

If the chrome itself is the toxin, then if it goes from one metal part over to another, why should the bath solution become toxic?  The chrome itself should be on the metal parts, not in the bath water?  Except for the brief time during the actual transfer process.

Not every form of Cr is directly toxic, but you still have to work with the toxic forms at some stage, no way around it. Plus, electroplating baths must have precisely defined composition with relatively high concentration of the chromium, otherwise plated surface won't look good or it will take eons to deposit the layer of necessary thickness. No way around it, and not because people didn't try to invent safer and better recipes.

[Planet_Lover]

I see.  So it appears to be a hopeless situation in terms of finding reasonable improvements.

That makes sense, because if reasonable improvements could be made to the process people would have done it already and chrome plating wouldn't be so expensive.

I'm restoring two antique cars I just bought.  They both have rusted pitted chrome parts.  To replace them, or re-chrome them would cost about $10,000.  That's not going to happen. 

So I'll go with my second option which is to just paint them gold.  I think they will look unique with gold painted chrome parts instead of silver painted parts.   And that will be a LOT cheaper for a DIY'er like me.   Buffed out gold-painted grill, bumpers, and door handles, etc will surely make a conversation piece if nothing else.

Because there's no way I'm paying ten grand for chrome.

[chenbeier]

10 Grand is to much , I guess 200 bucks should be enough to dip the parts trough the chrome line. Maybe you find somebody who is working in a plating shop., probably its cheaper.

[Planet_Lover]

10 Grand is to much , I guess 200 bucks should be enough to dip the parts trough the chrome line. Maybe you find somebody who is working in a plating shop., probably its cheaper.

If I could have the major pieces of the car chromed for $200 I'd go for that. One of the cars I have is a 1956 Buick Super.  The front bumper alone is huge.  Estimates I've gotten are like $3,500 just for re-chroming that bumper assembly alone.  I only looked on the Internet though.  I haven't really looked around to see if there are any local plating shops.  I'll keep searching.   If I can find a place to re-chrome that bumper for $200 I might go for it. 

[Enthalpy]

In addition to the toxicity of the metal ion: you also need a salt that is soluble. For some metals there is very little choice, like cyanide for gold.

Strip chromium from steel: specialized companies can do about anything, even when the base metal is much easier to corrode or dissolve than the capping metal. But don't expect the etchants or baths to be eco-friendly...

10k$ is obviously far too much. I too suggest to search for an other subcontractor. A few 100$ should suffice. Mention the size of your parts if they're big. These subcontractors can often strip the previous coating away and clean the parts; they do it faster and better than I could.

Metal plating is long, discouraging and costly to learn. It does need ugly baths, hence full recycling and adequate working methods to protect the workers and the environment. That's why it's a task for specialized companies. But thanks to volume and competition, the operation isn't expensive.