Parkerizing

[exeric]

I have been parkerizing parts on my '51 FL and would like to get some input from other people. Everything is going well but I am curious about color. I've had a lot of NOS H-D parts that were parkerized and the color seemed to generally be a dark greenish gray. I have seen a charcoal black and lighter gray. Is color determined by the manufacturer of the parkerizing solution or is it a result of temperature and immerion time ? I'm getting a charcoal black color.

[schmittm]

Eric,

Parkerizing solutions are based on phosphoric acid and usually contain either zinc or manganese. The process forces an electrochemical reaction with the outside layer of the part you are treating and deposits a coating of a metalic phosphate on the base metal. The zinc solutions produce a grey finish, the manganese solutions produce the charcoal black. You can specify which type you want from several suppliers that offer both types.

The greenish tint that is often present is usually the result of aging or patina that occurs after the part has been treated and is sometimes enhanced by the type of oil applied to the part following parkerizing. The greenish color can also be forced by adding copper to the initial parkerizing solution.

Final color is also affected by other metals in the iron alloy of the part.

You should not vary your immersion time to produce a desired color. As a general rule, when the part stops bubbling its done, take it out. Remember that the reaction does not stop even though you have removed the part from the solution, that's why it is critical to completely rinse the part in hot distilled water, dry it immediately and apply the protective oil coating.

mike

[exeric]

Thanks Mike. That answers why parts I did years ago look greener than what I've been doing lately. I would imagine H-D had a very precise process for in-house parkerizing but if parts were done by a vendor the color may vary.

[schmittm]

Eric,

The industrial recipes changed over the years so parts that came from the same manufacturer, even Harley, may appear different depending on when they were produced. Economy was the driving factor, trying to achieve the same level of protection using either less heat or shorter immersion times. During WWII manganese was controlled by the War Production Board so most of the parkerizing was done with either zinc or iron filings. The zinc phosphate yields a much finer grain surface and, as mentioned above, a lighter grey color. When you boil a part in phosphoric acid and iron filings you get a black finish but it comes out rather course and porous and does not protect as well.

some worthless chemistry trivia to brighten your Monday!

mike

[bmh]

I have seen in gunsmithing catologs that they sometimes list a finish color for the different kits. I'll look and see if I can find one in the next few days.
Brian

[Glenn]

color

let us know what you find I'm starting to do over a 50 pan to as close to original as I can

moose

[exeric]

The next big thing is to find someone to do the Cadmium plating. I did a knucklehead years ago and had my pick of 4 different local platers. Today, is a whole different story. The last cad plating I had done was for a '40 Chief. My source then was a plater in Wyoming of all places. I haven't checked to see if he's still in business but the shipping bill was almost 3 times the cost of the plating. I know this has been covered in other topics on this forum but if someone can make a good recommendation for a plater that will do silver cadmium plating it would be most appreciated.

[indianut]

Eric there is a place in Clearwater called Sun Glo Plating that will do your cad. They do nice work and as I recall charge by weight. They want the parts clean when they get them. As I recall they call the 'silver' cad Clear cad!

[T. Cotten]

This is hearsay (as I never plate anything anymore: If it must be plated, it arrives plated.)

I am told that all those yuppie-icon hybrid cars require special batteries that have swallowed the cadmium market. Last report was that the commodity has jumped nearly 500%.

Anyone on this Forum actually in touch with this industry?

....Cotten

[bmh]

I found a product called "copy-cad" that you can do at home .There was an article in Hemmings about it. Prices on the
"hobbiest" kits looked resonable enough, especially if you consider convenience. Process looks pretty simple too. It is real electro-plating without the cyanide and such. I am gonna give it a try this winter so I can let you know how it really does in the spring. Sorry haven't had time to dig out my gunsmithing stuff to see about the parkerizing kits yet, I'll try to do that this week
Brian

[T. Cotten]

I fake cad and parking all the time with other coatings,... but I think this discussion addresses the real thing.

It might only be a few years before "older restoration" takes on a whole new meaning. And value as well.

...Cotten

[Kojack]

Mance Plating is near me in Imperial, PA. They still do silver cad. They told me that the minumum charge is about $75 for a batch, which is whatever amount of parts that you want to send them that will fit in about half of a five gallon pail. They can do linkage, rods, etc up to about three feet long. They will pickle the parts and plate them but they don't do any other prep for that price. They told me the best way is to let them pickle your parts then give them back to you. Then you can file burrs, etc and glass bead blast them. Then give the parts back for the plating. This procedure gives the most even finish.

[exeric]

Thanks, this is some great information. Cotten, regarding simuluated cad plating, I am sure that I read an item in our club magazine that stated that the judging staff would now accept dull aluminum paint for genuine cad plating. This has been a few year ago and I have yet to come across that statement again. However, I was at Oley a few years ago and overheard 2 judges arguing over different hues of cad plating on the same bike. Obviously dull aluminum paint would not have made you any points with those guys.

Part of the fun of restoring motorcycles is tracking down stuff like this. Finding people that do work that isn't commonly done anymore, or replicating a finish that is not used (such as cadmium or parkerizing). I am not a nit picker by nature, which would be obvious if you saw my shop, but I do like to see things done the right way. I have seen this hobby go from just getting them running and looking nice, to obsessive, almost psychotic attention to detail. Lets face it, for some of our members, this is a nerds paradise and a playground for bureaucrats. . . . Where in the hell am I going with this ? Oh yeah, I just want this to stay fun.

Thanks Danny, I'll check out Sun Glo.

[T. Cotten]

If all of the cadmium (or all of the parkerizing) on a machine matches, it should be a fault.

Attached is a pic of a selection of NOS cad floatbowl pivot nuts, straight out of cosmoline. Not included are the completely bare ones from the same lot.

...Cotten

[schmittm]

We really should start a new thread, cadmium plating is not parkerizing but the objective is the same; protect the parts from rusting with an acceptable finish.

Like Cotten said, pure cadmium is getting scarce and expensive so you have to fake it. Home brew cad plating is very achievable and not that hard to accomplish. The Copy-Cad kit available from Caswell is exactly as the name implies, it is not 100% cadmium (its actually a zinc alloy) but the end results are nearly identical to original cad plate. The term "silver cadmium" thrown out in some of the previous responses refers to the final silver color of the part. Some variations of the process yield a greenish bronze color as seen on a lot of old automotive carbs, hardware and such.

The key to success is in the preparation. Cad plating is not bondo or primer. If you have pits, scratches, chisel marks, etc., the finished part will have cad plated pits, scratches and chisel marks. The parts should be buffed and absolutely clean and free of any oil or grease including fingerprints.

The basic steps are:
1. Prep the parts; filing, sanding, buffing, bead blasting. Spend most of your time here!
2. Clean the parts; this is the "pickling" stage. I boil my parts in caustic soda (lye) or strong detergent.
3. Thouroughly rinse the parts in distilled water to remove the soap, etc. Don't touch them, at this point I have everything suspended on copper wires so I can move them from one bath to another without touching.
4. Plate the parts.
5. Rinse again in distilled water.
6. Lightly hand buff with 0000 steel wool or equivalent. Apply wax or other protective coating.

That's it. I use a stainless steel stock pot on a hot plate to boil the parts in the detergent solution, a plastic diaper bucket full of distilled water to rinse, and the plastic pail that came with the copy-cad kit to plate. I'm as bad about dumpster diving as Cotten, my power supply for the plating operation is a discarded emergency lighting system, they have a great 6 or 12 volt rectifier inside them and you can even use the lights to help regulate the amperage output. A stainless steel deep fry basket is very useful for transferring batches of small parts from one solution to the other without actually touching them, works for parkerizing too.

I'll put some pictures of the steps in the next posts.

mike