Green Zinc Chromate or Green Zinc Phosphate Primers

[uglyjeep]

Hello,

I have some questions after researching the proper green zinc primer to use on the early jeeps. On my '42 GPW, a few pieces like the inside of brake drums and a pair of early "F" marked transfer case shifters, were primed with this green zinc paint.

Note the script "F" brake drum on the right...


After researching past posts on the site, many of the posts are referring to this primer as green zinc chromate, and after finding a source for this primers, I was told by the shop owner that zinc chromate is what is used for aluminum and galvanized surfaces, since it has some etching properties, and what I really needed was green zinc phosphate, which is more commonly used on iron, steel and welded seams. I found some corroborating evidence to this on the paint manufacturer's website. Other web information shows that the green zinc chromate was commonly used on air craft of the era, however many aircraft were using aluminum and alloy parts.

After spraying both types of primer, they both are very close in shade and difficult to tell apart.

My question is if there is documentation to which type of green primer was used on the early jeeps, the chromate or the phosphate? Besides brake drums and the transfer case shifters, which other parts should I expect to find with green zinc primer on an early (3-20-42) GPW? The Jeepdraw page mentions that early MBs had more than a few parts that were green zinc primed...

Thank you for your help,
Daniel

[uglyjeep]

A member contacted me, and mentioned that it may make a difference on what type of primer was used if the parts may have been government rebuild parts, which I have reason to believe may be a good possibility as my jeep, since on of the previous owners parts jeeps had a 1945 rebuild tag that came on it.

So ignoring my second question about what parts of a GPW were green zinc primered, my first question still stands....What type of primer is the correct to use...zinc chromate or zinc phosphate, as I have been told that thank you that they had different applications?

Thank you for your help!
Daniel

[lt.luke]

Ford built aircraft in WWII, so Chromate was in their inventory. If memory serves, my GPW had quite a bit of chromate on it. I was under the impression that that primer was an environmental hazard and not readily available, so I didn't document and try to find it. Heck, I can't seem to find bulk red oxide without ordering it special!

My tub may have even been primed in zink.

[uglyjeep]

Hello,

Both zinc chromate and zinc phosphate primers are readily available through marine and aircraft suppliers. I would not be surprised to find that the formulas have changed slightly over the years, namely the exclusion of lead in the modern formulas. That being said, it seems that zinc chromate, the stuff that Ford developed in the 1920s, is the more dangerous of the two paints. Zinc chromate is directly linked to skin ulcers and cancer

Zinc phosphate primer is apparently more inert, and the basic compound of zinc phosphate is actually used in some dental applications as a cement according to Wikipedia. I was also told by a marine paint supplier that the solvent compounds in the zinc phosphate paint are potentially more dangerous than the zinc phosphate itself...which doesn't sound any more dangerous than standard hardware and auto part store paints.

It is documented that Ford used green zinc chromate for aircraft, which makes sense, because aircraft construction uses a lot of aluminum alloy, which is what zinc chromate is designed to protect. Does this mean that Ford and Willys Jeeps were painted with zinc chromate as well, simply because Ford used it on aircraft at their assembly plants? This is where I would like to see documented evidence. From what I have learned so far, Ford and Willys should probably have been using zinc phosphate on steel and iron parts instead.

I have decided that I will not use the zinc chromate after learning about its adverse health risks, regardless of what is original or not, I will use the zinc phosphate. Seeing that the colors are so close between the two paints, choosing the safer one is the wise choice. Knowing which primer was actually used might also make me think twice about how I clean some of these old parts.

Daniel

[Jerry Hudgens]

I don't know what primer they used on the Jeep but I do know that zinc chromate primer is primarily used on aluminum and galvanized (zinc coated) surfaces. It can also be used on
steel. Typical zinc chromate primers are yellow ( I just bought a new gallon and its yellow).

Zinc Phosphate, Iron Phosphate and Manganese Phosphate are treatments for steel to improve paint adhesion, provide a degree of rust prevention, provide storage of lubricants on the surface, and provide improved metal forming properties.

I use iron phosphate on all of my steel parts prior to painting.

I would like to use zinc phosphate but I have no source for that.

I have never heard of a zinc phosphate primer, if they are talking about a liquid with a binder and solvent that you can apply with a spray gun and it cures/dries. I have heard of zinc phosphate as a metal pre-treatment but its in a liquid form (in water) that you spray on or dip the part in. It does not cure like a primer but it can be left on the part without rinsing. It dries when the water evaporates. Its an excellent pre-treatment for steel that is to be painted.

Jerry Hudgens

[Jerry Hudgens]

I tell you, not using zinc chromate because of some perceived health risk is over-reacting (in my opinion). You come in contact every day with zinc or chrome. Its almost impossible to not come in contact with these two metals.

Jerry Hudgens

[lt.luke]

This discussion has come up before and I want to say there is documentation. I don't need it, I have removed chromate primer from parts of my jeep. Steel parts.

There are two different colors, "yellow" and "green".

[Donovan]

Everyone,

I did a lot of research on this years ago as part of my job related to chemical usage at an old manufacturing plant that included WWII items (aluminum drop tanks, galvanized parts, etc.).

First, chromate: Typically chromic acid was used on aluminum and galvanized parts as it removed the oxidation that forms on the aluminum and zinc that the paint would not adhere well to. The chromic acid removes the oxidation and then etches the metal. The chromic acid then hardens and forms a hard yellow coating in 24 hours that subsequent paint can adhere to. Chromic acid (Cr+6) is extremely carcinogenic and restrictions prevent is use today although chrome platers I believe still use it.

Second, Phosphate: Also known as parkerizing, phosphoric acid was used to treat iron/steel by converting the rust to a iron phosphate that could reduce rust formation (not prevent it) and form a coating for good paint adhesion. Ford invented the process as part of the Model T/A process line I think.

I do not believe anyone is making a zinc chromate primer as I do not believe the Feds would allow it but I could be wrong. As for the zinc phosphate primers, this may be a derivative of the etch primers we see today but I have not researched the new materials, just what was used in WWII era.

FWIW,

Donovan.

[uglyjeep]

I tell you, not using zinc chromate because of some perceived health risk is over-reacting (in my opinion). You come in contact every day with zinc or chrome. Its almost impossible to not come in contact with these two metals.

Jerry Hudgens

I am not so sure Jerry. The elements of zinc and chromium by themselves are not necessarily the same thing as the chemical compound of zinc chromate in the paint. By themselves, they are elements, both are found in the human body in small amounts. Zinc is a necessary mineral for life, but too much zinc is harmful. Chromium is taken into our bodies through the environment, and there are some types of chromium that are not considered a health risk, but other types of chromium are mutagens or carcinogens. Polishing a chrome bumper, and taking our daily multivitamins is not the same thing as inhaling the fumes from the electroplating or leather tanning processes,...or inhaling zinc chromate paint dust while we sandblast or paint our jeep parts.



Excuse me a moment please....



I had put my laptop down while my six-year-old son gave me a hug goodnight, with my wife smiling behind him....hardly an overreaction if a simple, informed decision can increase my chances of being here even one moment longer.


Thank you for the replies , I do appreciate them.
Daniel

[uglyjeep]

I do not believe anyone is making a zinc chromate primer as I do not believe the Feds would allow it but I could be wrong.

FWIW,

Donovan.

Thank you Donovan,

Zinc chromate primer is still readily available to the public through marine and aircraft supply stores.

Here is one manufacturer....http://www.moellermarine.com/aftermarke ... s/primers/

Jerry, green zinc phosphate primer looks just like the green zinc chromate primer when applied. It dries like a regular enamel metal primer, with a flat limey-green color. Despite their similar appearance, their intended substrates, and their health risks are quite different.

Daniel

[Jerry Hudgens]

Well,

I guess its because I am old but I use zinc chromate primer a lot. I have also been using it over the years for a long time. I just bought a gallon about a week ago and I have already used some of it.

I am sure if you eat and inhale almost anything, the Feds will show you where that is carcinogenic. But, I don't eat and inhale the stuff. I just put it on steel parts and it cures and stays there.

Sodium and chlorine are very dangerous substances under certain conditions but combined they are common table salt that we all eat every day.

I am just saying that the right chemicals and products used correctly are really no big risk to your health.

Just my opinion

Jerry Hudgens

[uglyjeep]

Whichever products that you choose to use, just be careful. Since the effects of chemicals on one's health are not always immediate, and can appear only after prolonged exposure, I feel that this has a tendency to make people too comfortable with using some chemicals. Ben Franklin's words come to mind..."An ounce of prevention is worth a pound of cure". Presently there seem to be many primer choices which are safer, and perform better, than zinc chromate if you are only painting steel or iron.

For those of you using it or considering using zinc chromate, here is a health guideline sheet, that you may want to read.
http://www.osha.gov/SLTC/healthguidelin ... ition.html

I never intended this thread to become a cry for advocacy, but if the information helps some of you fine folks, I am satisfied with its change in direction.

Respectfully,
Daniel

[libbster29]

Old post. However what about the rustoluem zinc yellow primer. Would that work on a early jeep???

[Fabrizio]

For mine I will simply have epoxy primer/filler moxed to match an original sample, sprayed over a clear phosphate fluid, applied on sandblasted metal.
Better rust protection than almost anything else!

[lt.luke]

Old post. However what about the rustoluem zinc yellow primer. Would that work on a early jeep???

If I ever get judged and they scratch my paint to check my primer, we will have words.