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SJorgensen
11-06-2004, 05:09 PM
I'm dumping a waterheater so I thought I'd pull out the anode. As far as I know the anode is made of magnesium. I suppose I'll know if the shavings burn giving off a bright light. I also know that the powder and fine shavings are used in flashbulbs and other devices like that.

What properties are of interest to a machinist? What is the metal good for other than its chemical properties?

Thanks,

Spence

johnoder
11-06-2004, 05:46 PM
Light, even lighter than Aluminum

John

J. Randall
11-06-2004, 08:02 PM
Spence I don't know about water heaters, but I worked as a corrosion tech for a while in the oil patch, and we used mostly zinc anodes for liquid contact. The only time we used mag anodes was in earth contact. James

CCWKen
11-06-2004, 09:04 PM
LOL... Funny now but not at the time. I set one of my wood benches on fire power sanding Aluminum/Magnesium alloy. I still have about 30lbs. of it. What the heck is it good for. Corrodes faster than aluminum.

SJorgensen
11-06-2004, 09:24 PM
Well as you might expect the rod was heavily pitted and corroded. Still it would make a 4x4" cube. Can I melt it and treat it just as I would aluminum? Is there a hazard of it igniting in the crucible?

joahmon
11-07-2004, 10:46 AM
As a retired chemist, I strongly suggest that you NOT try to melt it. If it does catch fire, magnesium burns so hot it will strip the necessary oxygen from carbon dioxide ( one form of "fire extinguisher") and under some circumstances even water!! Also it will be so bright that if you look at it, you will not be able to see what you are doing. remember those flash bulbs? Think of a continuous light that bright.

Bob

Don Clement
11-07-2004, 11:09 AM
Magnesium is useful for igniting the Thermite made from the left over scrap aluminum and rust.

Don Clement
Running Springs, California

Spin Doctor
11-07-2004, 11:18 AM
We used to use Magnesium safety blocks in presses when work had to be done on the dies while in the press. Any time a set of blocks had to modified some idiot always had to collect the swarf from the saw. Although some of the guys did save it for using as firestarters for hunting trips out west

Don Clement
11-07-2004, 07:42 PM
Actually, magnesium doesn't work that well as a fire starter. Burns very hot, but goes out too quickly. Pieces of an old bicycle inner tube work best as fire starter.

Don Clement
Running Springs, California

SJorgensen
11-08-2004, 01:41 AM
Is there anyone else that thinks that melting the magnesium will be hazardous? I was thinking of using the same methods and cast iron crucible as I use on the aluminum.

JCHannum
11-08-2004, 02:52 AM
Yes, the heating of magnesium to melt is hazadarous unless performed in an inert atmosphere. My neighbor got some mixed in with aluminum,and quite a fireball resulted.

SJorgensen
11-08-2004, 04:17 AM
Well isn't the atmosphere in a forge pretty much inert? Once I adjust the gas and air I am consuming ALL the oxygen. I won't be going to as high a temperature to ignite mg. What about the reaction of mg to the cast iron? Aluminum steals carbon from cast iron and eventually warps the cast iron. What would the mg do?

joahmon
11-08-2004, 11:09 AM
If you decide to go ahead with melting Mg, be sure to have someone video tape the process; they will certainly win the "America's Funniest Videos" prize.

Bob

SJorgensen
11-08-2004, 01:24 PM
An important part of the planning for processes like this, is to be sure that there are no cameras or witnesses around. Even better if you have someone to blame it on!

shawnspeed
11-08-2004, 01:52 PM
When I was in High School, my metal shop teacher was a scrap hound, and funded many shop improvements by melting down scrap aluminum and getting top dollar at the salvage yard .(the school didn't charge the gas bill to his yearly budget) We recived some used VW engine cases that looked like aluminum,(VW Casesare a Mag-Aluminum alloy) so we cut them up small enough to get them in the # 6 Cucible and fired up the GAS FURNACE. Loaded it up and preceded to melt. In about 10 minutes, there was a blinding white light emmiting from both top vents, the door gaps, or any other opening avaliable...the instructor promply turned the furnace off and let it set for a few minutes as he suited up in his full foundry suit with welding helmet to remove crucible from furnace. upon removal,looking through a welders helmet .. you could see a piece of the VW block sputtering around in the melt of aluminum...this continued for about a hour until it found a little defect in the crucible and proceded to BURN THROUGH the crcible. The cruible was placed outside, with a steel drum over it for about another 4-5 hours until the reaction ended. 10 dollars scrap for a 60 dollar crucible wasn't such a bargan. Luckily no one was injured and the only loss was the crucible..it could have been worse. Mag is melted in INERT ELECTRC FURNACES with a sheilding gas just like TIG/ MIG wilding. (MAG is readily welded with a tig welder)As in one of the above posts,I don't suggest melting or attempting to melt Mag at home unless you like AFV, or aspire to make the Darwin Awards....

reality checker
11-08-2004, 01:56 PM
Magnesuim can and is melted and cast every day. You need to have an inert gas (very expensive SF-6) or a salt flux ( corrosive)to keep it from burning up.

Most of the higher quality cordless tools are die cast magnesium since at 2/3 the weight of aluminum you can cast magnesium, and add the weight difference back with extra battery. Same for any hand held computer or cell phone. In many market sectors it is looked at as a premium material.

molds for magnesium last longer than molds for aluminum since the molten magnesium is "easier" on steel. Many people can cast aluminum, casting magnesium takes more experience.

Yankee1
11-08-2004, 02:26 PM
Spence
I too believe that material is zinc.
Zinc is normally used as a sacrificial material to prevent damage. Boats use zinc anodes on their hulls to prevent electrical material transfers.Magnesium is used for the fire starters, the type that you cut pieces off of with your knife.

SJorgensen
11-08-2004, 02:55 PM
I could be wrong, but I've always understood that the sacrificial anodes in water heaters were made of magnesium. Maybe it tastes better than zinc.

tonydacrow
11-08-2004, 06:54 PM
Too much zinc is poisonous. Maybe that's why (as I've heard) they use mag anodes for water heaters.

SJorgensen
11-09-2004, 03:00 AM
Maybe what I'll do is put all the chunks of corroded anode in a tin can and top off with salt. Then dig a hole and put a weed-burner torch on it till it turns red. That should give me a nice little chunk of magnesium to keep on my shelf. If a bright light comes out of it I can apply the shovel. I don't want a Darwin award but I also don't want to fear irrationally.
Knowledge is power.

Thanks guys,

Spence

Evan
11-09-2004, 03:18 AM
Water heater anodes may be made from magnesium, aluminum or zinc.

My dad, a retired science teacher had a two pound block of sodium that he had kept under kerosene for years. He finally decided to get rid of it but you can't just throw it in the trash. He took it to the end of the Berkeley pier and hucked it into the bay. The kerosene, being an oily fraction, protected it for a time. As the water began to reach the surface of the metal an increasingly violent reaction ensued. By the time he had made it to his vehicle it seemed that a small nuclear attack had happened. It not only burns, it does so by dissassociating the hydrogen and oxygen atoms in the water. They then recombine energetically. I don't believe it made the national news at the time but if it was done today it would.

[This message has been edited by Evan (edited 11-09-2004).]

SJorgensen
11-09-2004, 03:56 AM
That would be true of lithium as well. Some things like water too much.

RAdams
12-03-2004, 11:15 PM
Re: Zinc anodes and water heaters

Zinc is not used as a sacrificial anode in water heaters because at temperatures above 160F, zinc becomes cathodic to steel. So it ceases to be sacrificial and starts to accelerate the corrosion of steel instead.

Yes, most water heaters are operated under 160F but there may be hot spots where it gets above that. Better safe than sorry.

Zinc was and is used for galvanized steel water piping, where it functions well enough because the water in the pipe is generally below 160F. However I have noticed that rusting and corrosion seems to be worse in hot water galv steel pipes than in colt water galv. steel pipes.

Most water heater anodes are aluminum or aluminum alloy. These are identified by a smooth top on the bolt head that secures them to the top of the heater. Magnesium water heater anodes can be identified by a raised bump in the center of the bolt head. The two types should not be mixed in a water heater with two anodes: the magnesium will rapidly sacrifice itself to the aluminum, not to the steel.

rsr911
12-04-2004, 01:50 AM
Many of the early Porsche 911 flat six engines where made of diecast magnesium. At the time it was the largest and most intricate mag die casting ever. Porsche won some sort of engineering award for it. Also the term mag wheels comes from early alloy wheels, many of which where forged magnesium, like the legendary Fuchs wheels found on early 911s. The wheels are very light and strong. However the engines can give one fits since the studs commonly pull right out of the case. Some of their early trans, including the one in my car where mag also. In later years they switched to aluminum for the blocks as the horsepower went up.

I know the stereotype that people get of Porsche owners, it's funny when I pull up somewhere in my car and people are shocked to see a guy in greasy clothes get out of a "$70,000" dollar car. I paid $5000 for it, sold the original mag cased 2.0 liter engine and swapped in an aluminum cased 3.0SC engine and modified the carbs from the old engine to fit. The car is 38 going on 39 years old but with updated bumpers it looks much newer. The nice thing about the older ones is that they are light, mine is 2000lbs with 200 or so HP and 4 wheel disc brakes that'll pop your eyeballs out. Can you imagine another car in 1966 with 4 wheel discs, 5 speed tranny, dry-sump oiling, some had mechanical fuel injection (also largely made of mag), overhead cams, and hemi heads?

What can you do with magnesium? A lot, it depends on your imagination.

roninB4
12-04-2004, 08:56 AM
Isn't a Porsche just a VW with lockwashers? LOL (Sorry if I offended here) Wish I had one the older ones too...

Tuckerfan
12-04-2004, 05:19 PM
I'd really advise against trying to cast magnesium. We've tried a number of times at work, blowing argon through it, and we've never managed to not have a fire (thankfully, minor each time) when we've done it. We weren't even casting pure magnesium, but some kind of bizarre alloy that when cooled would shatter at the lightest touch.

rsr911
12-04-2004, 07:21 PM
<font face="Verdana, Arial" size="2">Originally posted by roninB4:
Isn't a Porsche just a VW with lockwashers? LOL (Sorry if I offended here) Wish I had one the older ones too...</font>

LOL, I've heard that plenty of times but only by those whom I've never taken for a ride. Part of the beauty of an older 911 is it's similarity to the VW beetle. Both cars are durable, simple and easy to work on. The aircooled 911 engine started life as a 2.0L through the years it made it all the way to 3.8 in limited editions and 3.6 in the standard 911. All the while these engines retained the same mounting points and bellhousing attachment, just like American V8's. I know guys with pre-73 cars running 3.3L turbo engines around 350HP. The early cars remind me in some ways of a knee mill, strong, dependable, performance oriented, no frills. With a rear engine you can't tell my car has manual steering, in fact everything is manual as it should be. The best part is that they've gotten so cheap that even us normal people can drive them. http://bbs.homeshopmachinist.net//wink.gif Did I mention my car has magnesium lug nuts? I thought they were plastic the first time I had one in my hand. I threw it at a buddy and scared the hell out of him. http://bbs.homeshopmachinist.net//smile.gif

What the others say is true, be careful because it is flammable. There are a few guys out there able to weld the stuff but it's rare. Mainly watch out for shavings.

wierdscience
12-05-2004, 01:28 AM
Germans love things that burn hot,i.e. hydrogen(Hindenburg)and Magnesium(VW,Porsch,BMW) http://bbs.homeshopmachinist.net//biggrin.gif

BMW v-12 aircraft engines of the WWII ear are quite rare,mainly because they where made from Mag.,seems they dissolve in fresh water leaving nothing behind but "metal lace".

rsr911
12-05-2004, 03:49 AM
<font face="Verdana, Arial" size="2">Originally posted by wierdscience:
Germans love things that burn hot,i.e. hydrogen(Hindenburg)and Magnesium(VW,Porsch,BMW) http://bbs.homeshopmachinist.net//biggrin.gif

BMW v-12 aircraft engines of the WWII ear are quite rare,mainly because they where made from Mag.,seems they dissolve in fresh water leaving nothing behind but "metal lace".</font>

LOL http://bbs.homeshopmachinist.net//biggrin.gif

I don't know about the fresh water thing though, there are a lot of mag wheels still around from the '60s and 70's. Personally I prefer the newer aluminum alloys to mag. Sure it's light but it's also weak in many cases, particularily on threaded holes. One correction to a previous post, Fuchs wheels where made in both mag and aluminum depending on the year and model. The last of the original style Fuch wheels was around the mid to late 80's on the Carrera after that the 964 came out with it's own unique wheels.

I've heard stories of rabid English car enthusiats using German parts as "firewood" LOL http://bbs.homeshopmachinist.net//smile.gif



[This message has been edited by rsr911 (edited 12-05-2004).]

wierdscience
12-05-2004, 12:42 PM
If a wheel were to catch and hold rain water for a period of time,it would develope black and grey spots,then pit,only the pits tend to run all the way through http://bbs.homeshopmachinist.net//biggrin.gif

Another thing to consider is their uses on boats,zinc for salt water and mag for fresh as a general rule.I have seen folks with closed loop engine cooling screw up royal and use zinc in the cooling system.Eats the steel blades right off the water pump http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by wierdscience (edited 12-05-2004).]

paulgrandy
12-07-2004, 08:39 AM
Could alway grind it up real fine and make a Thermite Grenade and put it on some neighbor's engine block that you don't like.

pkastagehand
12-07-2004, 03:13 PM
I was once working in a lab doing impact trauma research and was machining a triaxial accelerometer mount out of magnesium. Without thinking I blew an accumulation of chips off the work piece. Had an incandescent work light near it with a 150 watt bulb in it. A chip hit that bulb, started burning, dropped to the mill table and ignited those chips and some dropped to the floor and ignited those chips.

The stuff on the machine burned out pretty fast and while hot above didn't even get the table that hot. But the floor got a little warm for the linoleum floor tiles and a couple of them buckled before I got it out. I layed a plate of something (can't remember what the material was) on top of the fire on the floor and smothered it.

I then started collecting the chips and more frequently. Still have some somewhere. Used some to start a campfire in the rain and it worked even with wet wood.

Don Clement
01-15-2005, 10:59 AM
This might be of interest for those machining magnesium http://www.cnn.com/2005/US/01/15/indiana.plantfire.ap/index.html

3 Phase Lightbulb
01-15-2005, 12:08 PM
Magnesium filings mixed with a little bit of potassium nitrate will burn a hole right through a newspaper or payphone's change compartment.

It's usefull for those times that you don't have a quarter, but you've got Magnesium and Saltpeter.

-3Ph

Rustybolt
01-15-2005, 12:21 PM
<font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:
Magnesium filings mixed with a little bit of potassium nitrate will burn a hole right through a newspaper or payphone's change compartment.

It's usefull for those times that you don't have a quarter, but you've got Magnesium and Saltpeter.

-3Ph
</font>


Use enough of it and it can burn a hole through almost anything. We melted the bottom out of a 55 gallon drum.

3 Phase Lightbulb
01-15-2005, 12:29 PM
<font face="Verdana, Arial" size="2">Originally posted by Rustybolt:

Use enough of it and it can burn a hole through almost anything. We melted the bottom out of a 55 gallon drum.</font>

I remember someone that mixed some magnesium and saltpeter and placed it on top of a newspaper machine. It burned right through the top of the machine, and right through the stack of newspapers inside.

-3Ph

egpace
01-15-2005, 01:05 PM
<font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:
I remember someone that mixed some magnesium and saltpeter and placed it on top of a newspaper machine. It burned right through the top of the machine, and right through the stack of newspapers inside.

-3Ph


</font>

Just to clarify, saltpeter is potassium nitrate.

egpace
01-15-2005, 01:31 PM
WARNING! WARNING!

You really better have a good reason to use magnesium. On the plus side, it’s lighter & stronger than aluminum. Going against are the galvanic problems. Assembling a magnesium part to steel or bronze part is a CORROSION NIGHTMARE! Even installing a screw in a hole threaded in a magnesium part is a problem. Don’t take this warning lightly, do the research! You’ll hate your self if you invest 30 or 40 hours of set-up & precision machining into a project, just to have it disintegrate before you.

If you must use it, and can’t accept corrosion to take place you’ll need to get coated hardware to eliminate direct contact. Another way around this problem is to install specially coated inserts into the magnesium prior to assembly.

Insert info: - http://www.emhart.com/products/newfiles/news25.html

Corrosion info: - http://www.magnesium.com/w3/data-bank/article.php?mgw=217&magnesium=356

A final note:

It’s quite amazing that a process has been develop to INJECTION MOLD MAGNESIUM! Thin walled, super strong parts can be produced with this process. Check out the link below.

http://www.phillipsplastics.com/capabilities/metals/magnesium_injection.html

3 Phase Lightbulb
01-15-2005, 04:20 PM
<font face="Verdana, Arial" size="2">Originally posted by egpace:
Just to clarify, saltpeter is potassium nitrate.

</font>

I thought I already said that in my previous message.

-3Ph

Don Clement
01-15-2005, 04:36 PM
&lt;Could alway grind it up real fine and make a Thermite Grenade and put it on some neighbor's engine block that you don't like.
&lt;
Magnesium is not Thermite see:
http://www.allatoms.com/ThermitePage.htm

Magnesium can be used to ignite thermite however.

egpace
01-15-2005, 05:04 PM
<font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:
I thought I already said that in my previous message.

-3Ph

</font>

3ph
Ah yes, you did! I only read the last one...
Ed

egpace
01-15-2005, 05:16 PM
<font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:
I thought I already said that in my previous message.

-3Ph

</font>



[This message has been edited by egpace (edited 01-15-2005).]

halac
01-15-2005, 09:25 PM
Back in the late 70's thru the early 80's my dad and I had a lawn mower shop. One of the Main brands we sold was Lawnboy. On their walk behind models the deck was made out of magnesium. They actually had the word "MAGNESIUM" cast right into the deck. I remember taking a small piece that was broken off of the deck and igniting it with a torch. Can you say "Bright Light"?

Another time we found out how hard it is to extinguish a magnesium fire. Dad was in the process of removing the engine from a Lawnboy in order to rebuild it. One of the mounting bolts had rusted solid and the nut rounded off. Now Dad was aware of the magnesium deck and its hazards. But he was kinda in a hurry and proceeded to get the blue tip wrench out to cut that bolt off. Well he got it off alright. He also made a quick exit out of the shop pushing a bright white, flaming mower deck outside to a safe distance. Water seemed to make the fire worse. Being here in Florida sand is very available. A few shovel fulls of sand helped put the fire out. Luckily we had a replacement deck in our mower junk yard.

A year or two ago a machinist friend of mine gave me a billet of magnesium about 4" in diameter by 3' long. I was thinking at one time of making some mag wheels for my combat robot. I've never gotten up the nerve to machine it due to the possible fire hazard the swarfe and chips present.

Hal C.

3 Phase Lightbulb
01-15-2005, 09:51 PM
When I was a kid I had a really cool toy. It was a magnesium bar about 5 inches long, and about 1" diameter. There was also a large piece of flint epoxied to the magnesium bar and leather strap attached to the top with a broken peice of hack-saw blade attached to the leather strap.

You would scrape off magnesium from the bar with the attached hack-saw blade, then ignight the little pile of magnesium you made by striking the flint towards it with the attached hack-saw blade.

I don't remember where I got it but I had that thing for years.

-3Ph

3 Phase Lightbulb
01-15-2005, 10:02 PM
I just searched the web and found a "small" version of what I used to play with....

http://www.firestarters.com/art/maganim2.gif

I used to spend all day giggling/building my piles of magnesium though.. http://bbs.homeshopmachinist.net//smile.gif

-3Ph