Magnesium Camera Bodies

[VidThreeNorth]

". . .
What is new is that Sigma added an on-site facility for machining and processing magnesium just last Fall (2018). This is a big deal because magnesium literally can catch fire while you're machining it if you're not careful! If things do go south, magnesium burns very, very hot. Not only that, but pouring water on a magnesium fire only makes it burn even faster, and even CO2 fire extinguishers just fuel the blaze!

The potential risks involved meant that Sigma hadn't previously machined magnesium in-house, but as they've used more and more of it in their lens barrels, and particularly with the fp camera bodies coming down the pike, it made sense to bring magnesium machining in-house."

"Sigma Aizu factory update: Magnesium machining and Sigma fp body production!"
Published October 1, 2019 at 10:55 AM EDT, by Dave Etchells, Imaging Resource

Sigma Aizu factory update: Magnesium machining and Sigma fp body production!

The above notes about magnesium are not news to anyone who has studied the material. I learned it when I was a teenager and interested in cars. "Drag racers" loved "mag wheels". But they were not pure magnesium, or at least not the ones that I can remember -- they were aluminum - magnesium alloys. This is important for this discussion, because it points out that not only were the problems with magnesium well known, but so was the "work-around".

Back in the 35mm film days, we did not see magnesium bodies. The common metals were aluminum, brass and zinc. Aluminum was the lightest, and it might have been used with some magnesium mixed in. At any rate, I never bothered to worry about them catching on fire.

Magnesium bodies in camera have been around for a while now, and I have heard about them. But in truth, although "alarm bells" went off when I heard about them, I believed that manufacturers were probably using safer alloys.

As of today, I still don't know what anyone is using, but I am starting to worry. Good sense seems to be slipping away in many ways around the world, and the fact that magnesium is potentially dangerous might have gotten lost somewhere.

Seeing the quoted article alarms me because it seems to be saying that Sigma built their facility for safe working of magnesium because they really are using fairly pure magnesium. The problem is that after you buy the product, then all that danger is still there, but now it is "your problem". The danger does not stop after you finish machining the material, it is the material itself. It looks like they think that "cladding" (really just a fancy term for painting or coating) the material will keep it "safe enough". Have you ever seen a camera with chipped, scratched or otherwise worn paint? I have.

What could touch off a magnesium fire? Well the traditional worries are static electricity and sparks from "flint-like" abrasion. But now in this modern era we have a new one: Lithium battery fires. And yes, these fires have happened. They are rare, but they have caused death by plane crash -- at least once. Now we can start with a lithium fire and then add a magnesium fire to it. Does this sound like a good idea?

Anyway, I would appreciate if manufacturers would inform us whether there "magnesium bodied cameras" are using safe alloys rather than fairly pure magnesium.

Will I buy a magnesium bodied camera in the future? It's starting to look unavoidable. I don't know, but I don't really want one.

 

[Dacaur]

I would say your worries are unfounded. You are already surround by magnesium in consumer products. There are cars with magnesium engine blocks and body panels, among other parts. Laptops with magnesium cases, and several brands of camera already use magnesium cases.
In all cases these are actually magnesium alloys.

Yes magnesium burns hot, and yes it's ignition point is below the 1000° that lipo batteries burn at, but it actually takes several minutes of sustained high temperatures to ignite it, and it melts before it burns, so you aren't going to suddenly have a camera you are holding burst into a magnesium fueled inferno.....
When it really comes down to it, a camera on fire isn't good, no matter what it's made from. A fire hot and long enough to ignite a magnesium body, isn't going to be made significantly worse by the camera body.
Magnesium burns hot, but also fast....

 

[johngpt]

"Considerable misinformation exists regarding the fire hazard in processing magnesium alloys. It is true that magnesium alloys are highly combustible when in a finely divided form, such as powder or fine chips, and this hazard should never be ignored."
Mostly the wikipedia article suggested that working with magnesium in its various alloy forms is easy and safe and cost effective.
From: Magnesium alloy - Wikipedia

 

[RVT1K]

The amount of effort it would take to ignite your magnesium camera body is very high. You incur far greater risk by having lithium ion batteries around. Or leaving the house in general.

I worked in a machine shop that turned magnesium castings on a lathe. There was no need to panic. But we did keep a bucket of sand next to the lathe in case of emergency.

Magnesium is used all over where weight is a big enough factor to justify the cost.

Many don't appreciate that aluminum will burn as well.

 

[VidThreeNorth]

I would say your worries are unfounded. You are already surround by magnesium in consumer products.
. . .
In all cases these are actually magnesium alloys.
. . .

This is the crux of what I'm getting at. There are many alloys, but the characteristics are available to anyone really interested. All they have to do is state what alloy they are using for any pieces that might cause some doubt. For example, I think I would not worry about internal pieces in a lens. But if you put it at the outside of the body (which seems to be what these companies are doing) then I'd like to know that what the alloy is.

Quoting Wikipedia: "Considerable misinformation exists regarding the fire hazard in processing magnesium alloys. . . ."

Well that's an interesting claim. I haven't seen much written about the topic at all, so I can't see it being "considerable".

The amount of effort it would take to ignite your magnesium camera body is very high. You incur far greater risk by having lithium ion batteries around. Or leaving the house in general.

I worked in a machine shop that turned magnesium castings on a lathe. There was no need to panic. But we did keep a bucket of sand next to the lathe in case of emergency.

Magnesium is used all over where weight is a big enough factor to justify the cost.

Many don't appreciate that aluminum will burn as well.

Aluminum yes, and zinc too.

Overall, you guys feel about the same as I did about it. Basically, just trust them to use at least reasonably safe alloys. Lately, I'm not so sure I trust all these companies to do so. The more commonly it becomes used, the more the risks rise. I can't avoid risks that I can't get information about. That's what I'd like. Sufficient information to make my own choices.

 

[Original katomi]

If you are concerned you may consider taking the batts out when not in use.
I have had a camera heat up and start to smoke as I was holding it. I had plenty of time to take the batts out and put it down

 

[weepete]

It's nothing to worry about. If it really bothers you why not write to the manufacturers and ask? It's a very spesific query so wouldn't normally be in the information.

There are probably millions of magnesium alloy bodied cameras in the world and I can't find one report of the magnesium being an issue so I think you have put 2 and 2 together here and got 5.

 

[Derrel]

I used to have a Nikon 300 F / 2.8 AFS Mark II, which was the lens with the Magnesium Barrel components. It was super light for a lens of its length and speed, weighing around 7 lb and it had exceptionally good close focusing. I bought it around 2005 I guess,and it was a great performer. I sold it off a few years ago after I quit shooting newspaper sports. Shaving a pound or two off of a heavy piece of gear by using magnesium instead of steel or aluminum is a smart move. I do not believe that using magnesium components in camera gear presents much of a hazard. Magnesium engine blocks on the other hand? Not really a good idea, since there is a high chance of Fire in any engine.

 

[johngpt]

VidThreeNorth, that quote about 'considerable misinformation' was copied and pasted from the Wikipedia article I linked in my post. Prior to your question in the original post, I'd never considered safety issues about the magnesium alloy in my camera bodies and that started me googling. So I have no personal or research experience with what is meant by 'considerable misinformation.' I thought it interesting that the article said that specifically. It might be due to the proliferation of half truths and myths on the internet about many topics.

So far I've not experienced excessive heating from any of my three Fujis. No over heating from my old Canon 40D which was used to shoot soccer match after match after match. I did wear out the shutter release button on it.

I think those that have written about the batteries make a lot of sense.

 

[RVT1K]

Like I mentioned, I worked with magnesium in a machine shop. There are also magnesium covers on the engine of my motorcycle. Magnesium has been and continues to be used all over. The worries are unfounded.

Couldn't any secret, nefarious changes to the alloy just as easily result in a change in the opposite direction rendering it "safer"?

 

[Dacaur]

The most important part of my post above.

...it actually takes several minutes of sustained high temperatures to ignite it (magnesium), and it melts before it burns, so you aren't going to suddenly have a camera you are holding burst into a magnesium fueled inferno..... You would literally have to be holding a smoking/flaming (lipo fires make a LOT of smoke) just waiting for it to ignite, which it wouldn't...

We are talking about 800°F+ temperatures for several minutes. It's not like paper or wood its its not easy at all to ignite.
#1, the itty bitty lipos in these cameras wouldn't burn long enough to ignite the body.
#2, they couldn't burn long enough to ignite it even if you removed them from their plastic case and placed them directly touching the body, but in reality, there is quite a bit of "stuff" between the camera battery and body, so the flames from a battery igniting likley won't even touch the body significantly during their short but time. The most likely scenario if the battery did fail catastrophically is the battery door would blow open and if the battery were not ejected, most of the heat would escape that direction.

 

[weepete]

It's not thermite. Air contains oxygen, oxygen is highly combustable....

 

[zombiesniper]

The magnesium alloy used in a camera body or lens would LITERALLY have to be cut with an oxy torch or a plasma cutter to have a half assed chance in hell of causing a problem. You could sit there with a propane torch all day and never set my 7Dmk2 on fire....aside from the plastic bits and seals.
I have a plasma cutter and have cut up some pretty suspect thing in my life. I've only managed to cause a mag fire once. Not a pleasant experience but I was prepared for the possibility.

If anyone decided that this was their preferred disassembly method then and only then would I be concerned.

P.S. If this is your preferred disassembly method.....please film and post will ya?

 

[VidThreeNorth]

VidThreeNorth, that quote about 'considerable misinformation' was copied and pasted from the Wikipedia article I linked in my post. . . . .

I understood that but my editing of the quote was poor. I have tried to correct it.

. . .

Couldn't any secret, nefarious changes to the alloy just as easily result in a change in the opposite direction rendering it "safer"?

Usually a "secret change" is done to save cost, so it depends on which is cheaper. It's possible.

After reading the discussion, I think I'm leaning towards not worrying for now. I still wish they'd state the alloys somewhere.

By the way, I thought about my Olympus OM-D EM-10. They never mentioned the metal at all, which means it is probably the cheapest, which would be zinc. The weight feels about right for zinc. Really, zinc isn't that much heavier when you realize that a camera body is "Swiss cheese"-like with lots of air holes.