Nuts and Bolts What to do?

[Carl Beck]

Is it Cad or Zinc?

It seems that some were Cad Plated and some were Zinc. It's been argued about for years.

I can only tell you the nuts,bolts,washers and other small parts I took to our Materials Lab were Cad Plated. {when I say "our", I mean Honeywell Space Systems}. They have several ways of identifying the specific compounds of any materials, and thus specify the proper handling and disposal procedures for recycling. I'll take their word for it.

Other people have had parts tested in one way or another - and were told it was Zinc.

Cadmium was commonly used in the US and around the world in the post WW-II period for corrosion resistance, up until it was classified as a Hazardous Material by the EPA { a heavy metal}. Which in turn subjected the Cadmium and associated plating solutions to expensive control, containment and disposal fees, as well as to EPA harassment.

Today other than a few Aerospace and Defense contractors or their suppliers - not many Plating companies will use Cadmium for anything. The Plating Shops that can use Cadmium, will charge about three times as much as Zinc plating, because of the additional costs of regulation. {which is not a problem for DOD or NASA}.

Shops that can't or don't offer Cadmium plating - will tell you it is the same as Zinc. Indeed the finished product can look almost identical. Also over the years the technology of electroplating has advanced and different compounds with Zinc can be almost as good as Cadmium in terms of corrosion resistance, but it takes very sophisticated plating control processes - and again it is more expensive.

Cadmium is about three times more durable in corrosion resistance than Zinc plating of the same thickness. Parts plated with either Cadmium or Zinc come out a dull sliver in color. The Bright Yellow finish with blue/red highlights is the result of a Yellow Chromate dip. That is another sacrifice coating applied over the top of either Cadmium or Zinc. {kind of a surface sealer if you will}

Given the appearance of nuts, bolts, washers found on now 40+ year old Z's - I'd have to believe that the guys in the Materials Lab were correct, and that most of the parts were originally Cad Plated. Zinc plated parts simply do not last that long.

FWIW,

Carl B.

Edited January 9, 2013 by Carl Beck

[Reverend]

Im currently restoring my engine bay and like to use the old bolts, i've heard someone used a tumbler or something to clean up the bolts, can anyone provide me a link for a cheap one? Im in desperate need of one.

[SteveJ]

Im currently restoring my engine bay and like to use the old bolts, i've heard someone used a tumbler or something to clean up the bolts, can anyone provide me a link for a cheap one? Im in desperate need of one.

Somehow I don't think this link will help you too much, but just in case someone in the states has the same idea...

http://www.harborfreight.com/catalogsearch/result?q=tumbler

I would check eBay, Amazon, etc.

[Zup]

Koalia---

Try and get a product called "Metal Rescue".

Amazon sells it.]

It is non-caustic and biodegradable.

It is expensive----about $25 a gallon---but will non-destructively remove rust from all of your fasteners and can be reused for quite some time before it becomes ineffectual. I've done approximately 25 pounds of fasteners with a gallon of it.

It only attacks the rust and will not damage rubber, glass or plastic.

I tried the tumbler approach and the results weren't very satisfying--lots of rust left in thread recesses and tight corners.

It will strip plating from metal if left in the solution too long, but the parts will be clean of rust and ready for re-plating or re-painting after rinsing in water.

It inhibits rust from reforming for quite some time, although it is not a final step.

I think if you try it you will like it's results.

Jim D.

"Zup"

Edited January 9, 2013 by Zup
source and spelling

[Captain Obvious]

Is it Cad or Zinc? It's been argued about for years.

Thanks for the details Carl. I've got a buddy who does a lot with antique motorcycle stuff and he often gets parts "cad plated". At least that's what they're telling him...

Next time he and I get together, I'll poke him a little and try to find out if it's truly cad or if it's really zinc. As you described, they come back dull silver, and not yellow. I've thought about including some parts with his orders, but the results don't look "right" for a Z car. Sounds like it may be a secondary process that could be split stream for his stuff and mine.

At this point, my Z is pleasure drive only and shouldn't see any inclement weather. Corrosion resistance for things like hardware is still important, but not as important as it used to be. I had not previously been interested in zinc plating, but Jerry's parts look good enough for me and it sounds like the corrosion resistance would be good enough for my application as well.

[JLPurcell]

In my research getting ready for my plating project companies I contacted said that Cadmium plating, due to the harmful nature and the EPA, is all but gone with the exception of the aerospace industry. The process is no longer cost effective for other applications. I am sure Carl better understands what they are talking about. One of the vendors that still does cad plating said that they mainly did fasteners for aircraft applications. jlp

[Captain Obvious]

Thanks Jerry. I suspect my buddy is getting zinc and doesn't know it.

How agressive was the wire brushing prep you had to do? Did you have to abrade off all the original plating, or just get the big chunks of grease and rust off?

[JLPurcell]

Thanks Jerry. I suspect my buddy is getting zinc and doesn't know it.

How agressive was the wire brushing prep you had to do? Did you have to abrade off all the original plating, or just get the big chunks of grease and rust off?

Philadelphia, I spent a lot of time and money in your city. My son went to LaSalle University.

I wire brushed the plating off for the most part. I took the rusty fasteners with the phillips bit heads and mounted them on a board and had them fine bead blasted , (just the heads), prior to wire brushing. I am going to try the above product "metal rescue" to see if this will work better than the blasting for those areas that the wire brush will not reach. The problem with that is that I do not believe that the "metal rescue" will remove the paint from down in the phillips bid area of those fastners causing me to still have some parts bead blasted. I found that wire brushing the parts leaves them somewhat polished which seems to leave you with a smoother and brighter finish when plated "out come = to input" You do not have to remove all of the plating but the vendor told me that if you don't it, for a good outcome, it adds a step to the process I had them take that extra step. JLP

[HS30-H]

Is it Cad or Zinc?

It seems that some were Cad Plated and some were Zinc. It's been argued about for years.

I can only tell you the nuts,bolts,washers and other small parts I took to our Materials Lab were Cad Plated. {when I say "our", I mean Honeywell Space Systems}. They have several ways of identifying the specific compounds of any materials, and thus specify the proper handling and disposal procedures for recycling. I'll take their word for it.

I'd rather trust Nissan, thanks.

As has been discussed so many times before on this forum, there's almost nothing on the early Z cars that was Cadmium plated. Almost everything that was plated was Zinc plated, and the characteristic 'yellow gold' of many nuts, bolts fasteners, brackets and other nick-nacks is simply a passivated finish added after Zinc plating.

From Nissan technical manuals: 亜鉛 ( 'A-en' ) = Zinc.

[Captain Obvious]

Jerry, Glad you had enough moolah left after LaSalle to do the Z car parts.

Thanks again for the details. Sounds just like what I usually hear. Want nice clean shiny smooth results out? Then provide nice clean shiny smooth results in. GIGO.

OK, now for the (hopefully not) million dollar question... How much? What did you pay for that tangle of parts?

[JLPurcell]

Jerry, Glad you had enough moolah left after LaSalle to do the Z car parts.

Thanks again for the details. Sounds just like what I usually hear. Want nice clean shiny smooth results out? Then provide nice clean shiny smooth results in. GIGO.

OK, now for the (hopefully not) million dollar question... How much? What did you pay for that tangle of parts?

Two trips to Muncie, IN 40+ miles each way and their minimum fee. Like I said they are good people and do "car guys" stuff basically as a favor. PM sent.

[motorman7]

Is it Cad or Zinc?

Parts plated with either Cadmium or Zinc come out a dull sliver in color. The Bright Yellow finish with blue/red highlights is the result of a Yellow Chromate dip. That is another sacrifice coating applied over the top of either Cadmium or Zinc. {kind of a surface sealer if you will}

.

Hi Carl,

Nice commentary on the plating. The only item that seemed off was the ‘dull silver’ of the plating and the yellow chromate making it shiny. In my plating experience, dull silver will result in dull chromate. If it’s not shiny coming out of the zinc plating bath, the chromate will not make it shinier. Additives to the zinc plating bath allow you to adjust the ‘shiny factor’. That’s the nice feature about doing this at home.

Also, to get the ‘rainbow’ effect, I use a short 20-30 second dip in blue chromate before the 1-2 minute dip in the yellow chromate. Warm DI rinse after this and heat dry and you are good to go.

A couple other comments on the whole bolt thing:

1. The easiest way to go about this is to order new nuts and bolts on line as a number of others have noted. Unless you are going for a ZCON gold medallion, very few people will notice that your bolt heads are off. Only the few of us anal retentive Z-junkies will notice. Just make sure they are quality parts.

2. If you do send your parts to a plating service, they will throw all of the parts in a big bucket and leave you to sort these out. Even with great pictures it will be difficult to get the correct bolt in the correct hole for final assembly. Just something to consider. If you install the wrong bolt in the wrong place and try it in several other places, now you have worn your plating off.

a. Another issue with sending out to plate is you may not like the plate job. Parts could come back dull, too dark, etc. (That’s why I started doing my own)

b. If you go this route, make sure you have all the parts you want to plate in that batch. Will cost time and money to go back for second and third plating batch.

c. If you don’t do your own prep work, this gets expensive as you will pay by the hour for them to wire wheel/sand blast your parts. Also as stated here several times, GIGO, the parts have to look good and clean before they go to the plater.

d. No guarantee you will get the parts back that you sent in. You may get some additional, may lose some.

3. If you do choose to do your own plating, it will cost about $500 for a decent set-up. I personally use the Caswell product with a B-K power supply. ‘Blue’ has a very good write-up on the whole plating process which would be good to read before moving in this direction.

a. Only go in this direction if you plan on doing this on a number of cars, otherwise it is not very cost effective.

b. The beauty of this is that you can plate whenever you want and get your parts done same day if needed. You can also make adjustments to the system to get the exact finish you are looking for.

c. Also, I use the zip lock baggy method and label all parts in small batches. When I plate, I plate one baggy at a time and keep them organized. Makes assembly much simpler and saves time searching for parts. Zip-loc’s, one of the best tools in my tool box.

Anyway, just my thoughts and good luck.

Best regards,

Rich