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WARNING about hexavalent chromium in zinc chromate and alodine

J

jantar

Member
When I started my project I was convinced I needed to build a lasting airframe. I changed my mind very quickly in favor of making sure I will be around to fly my aircraft. I personally think playing with Alodine and/or zinc chromate primers is really a bad idea. According to Occupational Safety and Health Administration it is almost impossible to protect workers in a workplace environment. Please read the article below and come up with your own conclusions.

http://www.msnbc.msn.com/id/11596343
 
Good point, I use zinc chromate for my non-alclad pieces, but spruce also sells something that is suppose to be better for you. I forget what it's called but it's the same color and can as the Zinc. I want to switch to something that works better on scratch resistance, but might not.
 
Good info thanks

http://www.aircraftspruce.com/catalog/cspages/zinc.php

See warning at bottom. I remember 10-15 years ago this came out and thought they where going to stop selling Zinc Chromate to the general public, apparently not. I use two part epoxy primer in a spray gun when I want to do the full meal deal protection for items like extrusions. However you need to protect yourself from this also. All chemicals are hazard. George
 
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I do not want this thread to turn into a primer war. The message here is simple. Some chemicals are particularly nasty and hexavalent chromium is one of them. Even if you protect yourself while spraying you still have to deal with fine particles in the air or on painted surface. It is almost impossible to fully protect workers at reasonable cost. It means it is extremely unlikely we will ever be able to fully protect ourselves in our home environment.

Please, look at alternatives, do yourself a favor.
 
osxuser said:
Good point, I use zinc chromate for my non-alclad pieces, but spruce also sells something that is suppose to be better for you. I forget what it's called but it's the same color and can as the Zinc. I want to switch to something that works better on scratch resistance, but might not.
Click to expand...

Zinc oxide is the less hazardous alternative. I use them both. The only real problem I have with Zinc oxide/chromate is that it takes some time (up to a few days) until you end up with a bullet proof finish, i.e. hard and scratch resistant. After that, though, the Zinc stuff will be hard as a rock.

-John
 
ET go chrome

I pretty well ignore government proclamations regarding health, except where legally demanded at work. Flip flops on asbestos (from must use to can't touch even if inert) and MEK (OK, not OK, OK) are cases in point. Heck...Eggs, chocolate and booze are all good for you now. (Not that I am complaining, of course).

I'll keep using chromium products and take the risk. They work.
 
Just remember that the government regulations presume that you're being exposed to it every day in the workplace. I prime about twice a month, outside, for a couple of hours. Sure, we want to reduce exposure as much as possible, but until they come up with something that works as good or better I'll keep using the chromates.

PJ
RV-10 #40031
 
Anyone that has used the Oxide, does it work as well as chromate? I'm willing to spend the extra money if it works as well, but usually "health conscience" replacements don't work as well.
 
The Oxide worked well for me... except that the nozzle kept getting clogged (I don't think this is a problem just with the oxide version). Also, my plane is nowhere near finished, so I can't say anything about its protection qualities.

However, I have switched to SEM (and before that the PPG version SX ????) self-etching primer. I like that I can buy it locally and it dries really quickly. BTW, if you do decide to buy the Zinc Oxide, do a google search for it. I found a source that was a fair amount cheaper than A/S and delivery was fast. Sorry I don't remember where. If I run across the receipt, I'll pass it along.
 
I get all my oxide/chromate from Redden marine supply. Here's one thing re: the application: in at least the case of the chromate, there's two colors, green and yellow. The yellow goes on about 15 baggilion times better than the green. I think the zinc chromate dye is yellow naturally, so maybe it's whatever they add to it to make it green that screws it up. I dunno.
 
Yes

You are right! I have yet to come across an example where the government was on the safe site with respect to chemical exposure limits. Look at Europe they have far lower standards than US for most chemical exposures and some we use are banned over there. EU bans some of them for a reason.
 
Be careful

I don't know enough about these chemicals to say what limits should be imposed or whether or not they should be ban. However, I would caution against using reasoning such as "The EU bans them for a reason" to support a position. Many (probably most) times these decisions are made for political purposes rather than rational purposes. The ban may simply be to reduce competition for one of their firms. Likewise, the US's lack of a ban or looser regulations may be for the same reason.

I'd look to the scientific community for what is more likely solid research. Even then, I want to know the source of funding for the studies. Yes, I know I am a cynic. But when I see that Pfizer funded a study that found one of its drugs is safe or one of their competitor's drugs is harmful, I just ignore the findings.
 
Overly cautious?

I know you can?t believe much of what you see on TV but regardless, there is enough concern that I have decided to use primer that doesn?t have this ingredient. (I was really trying for humor in my first post).

Personally I?m really not comfortable using anything that requires/recommends wearing a space suite during application. It?s just personal preference. It?s not as critical for me because I have decided to only prime the ?contact? areas in an effort to minimize weight.

As it is with engines, instruments, and paint color it really boils down to your preferences. In my opinion that?s the coolest aspect of building an experimental (and sometimes most frustrating), you get to make the decisions. :cool:

Donald
RV-8 Empennage
N-284DP Reserved
 
No, You Really Can't Be Too Cautious

...because virtually every product used for painting and lubrication (including seemingly innocuous things like WD-40) contain chemicals that can fool you because the damage isn't immediately evident.

I owned and operated an auto collision/paint shop for 23 years but got out of it entirely in 1995. All that time, I was pretty loose about using protection from all the various paints and chemicals used. Now, it looks likely that those years have come back to haunt me.

I was just recently diagnosed with leukocytosis (a symptom, not an ailment), but I won't know exactly what flavor of blood disease I have until the tests are back from the bone marrow biopsy (like, aaah, ouch).

In my case and with my history, however, the most obvious and likely cause comes down to benzene exposure which is one of the chemicals singled out that can lead to blood disease over time.

So while I can't turn back the clock for myself, I can offer a clear warning today to those of you who think you can just wash your hands after using the various nasty stuff we do; it don't work :eek:

As far as banning things that might be harmful; nonsense. All these products have a purpose, and all that is needed is labeling that outlines the risks and how to mitigate them. Then, as adults, we make our choices and live with them.
 
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Two points.

First, don't think that because you are not using zinc chromate every day that you are OK. Carcinogens are not thought to have a threshold of exposure below which they are safe. Each exposure, even a small one, increases you risk of contracting cancer slightly.

Second, Scientists have not flip-floped on the toxicity of hexavalent chromium. There is pretty much universal agreement that chrome is one of the most potent carcinogens (about 5000 times more potent that benzene according to the state of California). And no, that's not based on rat studies. It is based primarily on epidemiological studies of people that worked making chromates.

If you like zinc primers, use the zinc oxide. I find that it works just as well for me.

Tom
 
Highflight said:
....I was just recently diagnosed with leukocytosis (a symptom, not an ailment), but I won't know exactly what flavor of blood disease I have until the tests are back from the bone marrow biopsy (like, aaah, ouch).
Click to expand...

Not in the least degree to under value the statements about being protected from toxic substances, but I believe there are ways to reverse many blood ailments and cancer.

I have a friend who might be able to help you. He runs a clinic in the Palm Desert of California. Really nice guy. He won't charge you to talk and give advice. He has a great 10-day program to get you started if you like what you hear. I highly recommend it. (Cheap too)

David

Here's his number:

Mike Casey
Director
Restoration Ranch
760-364-3462
 
Poly=Many, Tics=Blood sucking insects

Political aspects are there, even if hexavalent chrome is an agreed bad actor and politics don't apply in its case.

A funny politics example was a regulatory meeting near DC I attended some 15 years ago in regards to CFC's. Some panel members we pretty flaky and made comments like "All chlorines are bad and should be banned". I asked about Sodium Chloride and they responded "Of course it should be banned"!. When I informed them it was table salt, the response was "Well... too much salt is bad for you too". :rolleyes:

Anyway.... I still say playing with mercury on a tabletop was fun.......... :eek:
 
A talk show hosts in Atlanta once made an announcement that the Atlanta water system had high concentrations of dihydrogen monoxide. He had many people upset. Someone from the water department called up and denied that there was any dihydrogen monoxide (H20) in the water. :D

Then there was his description of the "cat chasing" (throw cats out of an airplane and have skydivers try to catch them) tournament that was held one weekend. :D

Vern, I am with you. Provide us with accurate information so we as adults can make our own decisions.
 
Abandonded Alodine and Chromate

I for one have completely abandoned the use of both alodine and the hazardous primers and paints. I have been using the Aircraft Finishing Systems http://www.aircraftfinishing.com/ products with really good success. I clean/etch in one step and spray in the second. The primer sealer is as hard as nails when it is on, is totally non toxic and requires only a paper mask when spraying. For me it is the only way to go.

Charlie Becker
N464CB (8A)
Mounting the empennage.
 
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