Making Magnalium.

[jacob]

First off I'd like to say all credit for this method goes to tentacles and FrankRizzo, I'm just showing exactly how I do it.

 

 

What you'll need.

 

PPE (personal protective equipment) this is a must, WORKING WITH HOT/MOLTEN METAL CAN BE DANGEROUS, the method described here is somewhat gentle but still deserves great respect, Leather gloves and safety glasses are minimal, a full face shield and long sleeve welders jacket is even better.

 

Charcoal, I prefer briquets because of their uniformity, but lump should be useable. you'll also need airfloat to use as a flux, (more on this later)

 

A "chimney style" Charcoal starter, they look something like this,

Link

or this,

Link

Basically just a metal can with air holes through the bottom used to light Charcoal before you put it in your grill, for our purposes however we'll be leaving the Charcoal in the starter the whole time.

 

Soup can(s), I prefer the slighty larger "Campbells chunky" cans, they're just right for about 700 gram batches.

 

Something to stir the melt with, I use a piece of rebar.

 

Optional: a shallow water bath.

 

And last but not least, Aluminum and Magnesium, Aluminum is super simple to find, any scrapyard in the world should have loads of it for dirt cheap and as far as I know, purity of scrap Aluminum isn't an issue, or you can pre melt your own scrap Al (cans, ladders, car parts, etc) pour it into ingots and use that.

 

Magnesium is abit harder to get, I've only ever found it at a scrapyard once and the man I talked to said he was selling all he had the next day, I bought 10lbs at .50$ per lb, don't know what current prices are like.

 

My current soruce of Magnesium is mostly from a 15lb ingot I bought off ebay, Lawnboy pushmower decks are said to be pretty pure Mg although I've never used any, also, the lower radiator support brackets on (I think) 2004 and newer Ford F150 pickup trucks are an alloy of 5Al/95Mg, and old VW beetle engine blocks are an alloy of Magnesium but I'm not sure what it is.

 

A good way to test if something is Mg is to scrape it and expose fresh metal, then pour on some household vinegar, it will bubble and fizz if it's Mg.

 

Getting the alloy right.

This is important, you want to make sure you have a true 50/50 alloy by weight or it won't be brittle enough to break easily.

 

For example, I have 92% Magnesium and 100% Aluminum, so for a "true" 50/50 mix I need to weigh out 100 parts Magnesium and 84 parts Aluminum, when mixed this gives me 92 parts each of Magnesium and Aluminum (or close enough) you may want to add a few more grams of Magnesium to replace what burns off.

 

Acctually makeing it.

 

Ok, time to make some Magnalium, the first thing to do is weigh out your Magnesium and Aluminum, I use 400 grams of Magnesium and 336 grams of Aluminum, this gives me 736 grams total which is just about right for a "Chunky" size can, depending on what you use for your metals you may need to break them down to fit in your can, I cut mine up with a bandsaw, works great,

http://www.apcforum.net/forums/uploads/1217005379/gallery_509_7_443340.jpg

Aluminum and Magnesium aren't particuly tough though, so almost any metal cutting saw will work.

 

Next put some charcoal in the bottom of the starter, put in the can (with part of the Aluminum in it) and fill around with charcoal, it should look like this,

http://www.apcforum.net/forums/uploads/1217005379/gallery_509_7_892118.jpg

 

Light it up and wait, once all the Aluminum is melted (I add it piece by piece rather then puting it in all at once) skim off the slag (if there's alot) it should look about like this,

http://www.apcforum.net/forums/uploads/1217005379/gallery_509_7_486514.jpg

 

Now start adding the Magnesium, once you start adding the Mg don't waste any time, it should slowly melt like a sugar cube in a cup of tea, stir around to feel for lumps and once it's all melted in stir it well to mix, you should have some small flare ups but it shouldn't be too bad, now cover the melt with plenty of airfloat charcoal (you got that out before hand right?) and take it out of the starter, you can now leave it to cool down in a safe place, or you can slowly and carefully cool it down in a water bath, I always use the bath, you don't need to cool it off all the way, just below its ignition temp, in fact make sure you don't leave it in the water too long or it may hold water and react when you powder it.

 

Magnesium Fires.

If somehow, someway, something goes horribly wrong and you need to put out burning Mg DO NOT USE WATER that will only spread it around and make things worse, use a dry powder, sand is best, or dirt, as far as I know the only effective way to control a Mg fire is to smother it with something that won't burn, CO2 won't even work on a Magnesium fire. (need I say do this outdoors)

 

Once it's cool to the touch, peel off the can and wire brush off the slag (wear gloves and glasses, the can and Magnalium peices are sharp and like to fly around) it should look about like this,

http://www.apcforum.net/forums/uploads/1217005379/gallery_509_7_1060859.jpg

(Note, that ingot isn't brushed)

 

You're allmost done, just need to smash it up, which is quite easy, to give you an idea of just how brittle well made Magnalium is here is a picture of the above ingot after I dropped it sideways on a concrete floor from about 3' (1 meter)

http://www.apcforum.net/forums/uploads/1217005379/gallery_509_7_170003.jpg

 

A few minutes later with a small pair of pliers and I had this.

http://www.apcforum.net/forums/uploads/1217005379/gallery_509_7_206591.jpg

 

The above lumps can be further ground down in a meat grinder, ballmilled with some hard media and screened (I've yet to ballmill any though) and I recomend a respirator, fine, airborne Magnalium dust is a respiratory irritatent, trust me I know

 

 

 

Well that's it, I'd like to thank FrankRizzo and tentacles for this great method and questions/comments are welcome

Edited July 29, 2008 by jacob

[Swede]

Great tutorial, Jacob, thanks. This is an awesome way to melt small batches without having to invest in expensive stuff like foundry furnaces and such. Question - what is the purpose of the AF charcoal after the melt and mix is complete?

 

I think a good part of this tutorial would be suggestions from people for additional sources of magnesium.

[FrankRizzo]

Airfloat charcoal is dumped on top of the molten metal to smother it from oxygen as the ingot cools and solidifies. The charcoal will start to burn/off-gas and create a very fuel rich atmosphere. Additionally, the can with the molten metal should be cooled as quickly as possible. Tenacles and I used a bucket with a shallow amount of water and a firebrick in the bottom to prevent the can from melting through.

[Pretty green flame]

Sulfur supposedly stops magnesium fires, from what i've heard it's pretty effective at it.

[FrankRizzo]

Sulfur supposedly stops magnesium fires, from what i've heard it's pretty effective at it.

 

Alan Yates has his head up his ass. This idea about using sulfur is brought up almost every time magnesium melt flare-ups are discussed, by guys who've never tried it. Sulfur does hardly anything to stop the flare, and reacts with the metal. It also *stays* on the metal and keeps it stinking to high hell as you're processing, using, storing, etc. Tenacles had a bag of crushed magnalium that he had tried using sulfur on during the processing, the stuff smelled like a stinkbomb every time the bag was opened. Not a good idea.

Edited July 29, 2008 by FrankRizzo

[Bonny]

Alan Yates has his head up his ass. This idea about using sulfur is brought up almost every time magnesium melt flare-ups are discussed, by guys who've never tried it. Sulfur does hardly anything to stop the flare, and reacts with the metal. It also *stays* on the metal and keeps it stinking to high hell as you're processing, using, storing, etc. Tenacles had a bag of crushed magnalium that he had tried using sulfur on during the processing, the stuff smelled like a stinkbomb every time the bag was opened. Not a good idea.

 

 

I had the same result when I tried to use sulfur...I'll never do that again.

I haven't tried dumping charcoal on top to stop the burning, though. I just scrape and wire brush the shit off the top...it works great in fountains so no real waste.

[jacob]

Same here with the sulfur, staink to high heaven.

 

I've never tried it without the charcoal on top, might do that next time but it's cheap so, meh.

[tentacles]

Jacob: Nicely done! One thing to mention, though, is that you will want a big pair of pliers to pull that can out with, it's going to be a bit toasty! I was thinking the other day it could be fun to do a class on this at PGI next year.

+

[FrankRizzo]

Tentacles,

 

I can bring the charcoal chimney, scrap aluminum, magnesium, and bear turds if you want to do an informal demonstration at PGI this year.

Edited July 30, 2008 by FrankRizzo

[tentacles]

Sounds like fun! Might be just the thing for that Passfire BBQ tuesday night. Don't forget the fire bricks, I'm sure we can find a bucket around.

[Arthur]

In the UK magnesium of good purity is used for sacrificial anodes on steel boats and in some heating systems so look in plumbing suppliers or marine fitters.

 

Also our leading amateur magnalium producer tips the molten metal into water to form granules directly these can go strait into a ball mill.

 

Regarding the fire risk. If you only make small batches then if it burns just abandon the lot. If you make larger batches then an inert atmosphere probably welder's argon would be a good idea. Or of course get an induction furnace in a vacuum chamber Strangely induction furnaces crop up on ebay occasionally.

Edited August 3, 2008 by Arthur

[Rogue Chemist]

I had a can melt through once when using a food can to make magnalium. I was using a campfire not a furnace, and my can-crucible was sealed so minimal air was allowed in. I also could not see in. The can was set directly on the coals. After about 30 min I took it up out of the fire and part of the bottom fell out, and a bunch of alloy flowed out, right into the fire, igniting instantly. I wasted no time chucking the rest of the can away from the fire, a small trail of glowing (not on fire) metal trickling out. The can and its contents were just oxidizing and I figured I had lost all the magnalium by now, as the can was glowing orange from the oxidation occuring, and powdery oxide was mushrooming out the bottom. I put it in a hole 1 foot deep, and buried it under some dirt. The spot was smoking for about 8h, and when the can was dug up, it was all oxide.

 

And thats why I only use the electric furnace for magnalium now. The fire still works for other high temp reactions though

[tentacles]

Rogue: what probably happened is your fire was oxidizing and burned the steel can into rust. We had this happen when we were blowing air up the chimney. That's why the chimneys work so great as is. Reducing atmosphere, lots of heat, etc.

[XinE895]

I used about the same method except in order to keep the Mg from flaring I took a bigger can, like a Pineapple juice can and cut it about an inch from the bottom to make a lid, one that doesn't just sit on the top, but also has a little lip going down the side. I put a screw through the top to make a handle. Then once all the AL is melted, I just put in the Mg chunk and set the cover over the top. Then I would check every few minutes to make sure the Mg was melted by lifting the lid just enough to catch a peek. Once it was all melted, while still leaving the lid on, I picked up the whole can/lid assembly and hit it a few times against the ground to mix, then let it sit to cool. No stirring or removing the lid except to check the Mg. I found this to be the easiest way to do this, that way you don't have to worry or mess with anything else, you just put in the Mg, wait, hit it a few times, and let it cool. I also found that just giving the can a few good smacks against the ground mixes it just fine, every time I've make Mg/Al it has always turned out great.

 

I also use new soup cans every time, in a steel bucket with a blower blowing into the bottom with standard charcoal.

[Swede]

Let me ask you guys... I've got a propane-fired mini-foundry that I use occasionally to sand cast parts:

 

http://www.5bears.com/pics/found03.jpg

 

The blower mixes propane and air into a screaming vortex, and a crucible of aluminum will melt in about 8 minutes. But the nature of Mg scares me a bit, having zero experience melting the stuff. Would the hell that is the inside of this furnace be a guaranteed ignition of the melt? Home foundry types use a variety of fluxes to clean the molten metal, with most of them forming a "skin" of molen salts or glass, in the case of borosilicate fluxes. Would a heavy dose of flux keep the mix from igniting? And if/when it does, is there danger of any sort of explosion?

 

I like the idea of pouring molten magnalium into H20. I think what I would do, though, would be to position a length of steel angle-iron that would carry the melt a short distance to be dropped into the water bucket. The thought of a glowing crucible being positioned above a bucket of water gives me the willies. If water is spattered into the crucible, it would flash to steam and could violently expel molten metal.

[jacob]

In that kind of environment (inside the furnace) it will surely ignite, thing is though, it will ignite in the charcoal as well, a small amount of Mg burning in open air isn't very, "vigorous" it pretty much just smolders really hot, but when you force air to it (blow on it, throw it through the air, burn it with an oxidizer, ect) it gets crazy.

As tentacles said, the reason why the chimney method works so good is the Reducing atmosphere, the charcoal takes up almost all the oxygen so the Mg can't burn, much.

 

I suggest taking a small piece of Mg and melting/igniting it with a torch, that way you can get a feel for how it will behave in a charcoal melt, and I wouldn't use that furnace for making Mg/Al, it will no doubt burn off too much Mg and could be dangerous, especially if your crucible burned through

Edited August 4, 2008 by jacob

[Arthur]

On a home/hobby scale te "bean can furnace" is OK If it burns then just dump it not much lost, and not much fire hazard, especially if done ourside or in a big building like a foundry. With your propane furnace yes there is a risk of the molten metal burning and it's a lot of metal which means big cost and big fire risk. If that lot full caught fire you probably couldn't run fast enough,

 

For bigger batches than the sub kilo lump in a bean can please look out a good type of crucible to preserve an inert atmosphere over tha melt all the time the flame is on. Or look at doing batches in an induction furnace. Finding a vacuum induction furnace or an inert gas induction furnace may be over budget!

[Swede]

Thanks for the head's up. That's a bit disappointing that I can't use my furnace. What if I were to adjust the mixture to make an exceptionally rich burn? Normally you'd adjust the air intake to produce a blue flame that roars like a jet engine. If I close the air intake a bit, the burn will collapse towards yellow, and should be just about devoid of oxygen. From there, a layer of AF charcoal might be enough to prevent ignition.

 

I may try it, but it will be a bean can quantity, very small, and with the utmost respect for what may happen. If it fails, I'll go for the charcoal chimney, which was a whopping $12 at a local home depot.

[FrankRizzo]

Swede,

 

You should be able to use your furnace if you can richen the mixture before adding the magnesium to the melt. You may even want to add some briquettes to the bottom of the furnace for extra oxygen scavenging.

[Bonny]

Swede,

Your furnace will be fine. Frankrizzo's idea with the charcoal sounds like something to try. I've made a few batches in a small propane forge. I used a SS bowl as a crucible and just put a lid (flat steel plate) over top. The MgAl did burn a bit when I stirred it up, but the results were fine. I allow it to cool with the lid on for several minutes and then dunk it in water. Just scrape off the crusty crap with a wire brush and use it in fountains...has a nice crackle.

[jacob]

Swede,

 

As Frank and Bonny said, if you can adjust the fuel/air mix on your furnace (richen it specifically) you may be able to use it, adding some charcoal in the bottom is a good idea, just do your best to keep oxygen away from the melt,

 

Somthing to watch out for is to make sure molten metal can't fall from the crucible if it breaks, molten Mg likes to suck oxygen from almost anything and you might have a very quick, very hot flare up if that happened.

[tentacles]

Finally found some of these stainless steel drink shakers the other day, and used them to make these:

 

 

 

Also used one today to make a batch of MgAl, worked beatifully for an approx 800g batch, I think they'd be suitable up to 1kg total material, much more than that and you'll start to get problems with oxidation. As you can see, they came with lids. I tack welded the little cups onto the lids. The crucible part warps a bit from the welds when it heats up, but you can cram the lid on still. Very happy with the results, no deterioration of the stainless so far other than the warping and heat coloration. The ingot fell right out when I tapped it lightly upside down after cooling. The densest MgAl I have made to date, very few pin bubbles in there compared to previous batches. Not sure what I want to do with the second one, though, I don't really need two of these. Maybe I should make a couple more and give 'em away at PGI?

[FrankRizzo]

Ah...those are the things you were talking 'bout. Nice! And a lid to boot..I think you've found an almost perfect crucible.

[tentacles]

Yeah, it doesn't self-heat, generate electricity or give me head, but I'm working on extending the features a bit.. You want the second one? Is anyone else interested in one? Frank, what do you think of me whipping up a couple more of these to raffle off at next year's PGI, if we do that magnalium class? Proceeds to JPA of course.

 

The functional part of the handle even stays cool the whole time. I was even able to give it time after adding the last piece of Mg to fully melt without it starting to burn.

Edited September 15, 2008 by tentacles

[Nitrato]

Jacob, Great tutorial

 

After the method used by Tentacles and FrankRizzo, making MgAl cant be simpler.

 

Here where I live, "charcoal chimney starter" arent very commom, people here prefer using ethanol to start the charcoal (this is somewhat a dumb thing to do if you dont take proper care and this has injured many people).

 

I just used a large paint can perforated (several holes) at the bottom and that suspended with two bricks (to give air chance to enter through these holes) as a improvised 'chimney'.. and worked great...

 

Below is my part of my first (and at present moment my only 'play' with MgAl making) amount made with that process, this photo was made with a camera from a friend... A very tiny amount (I've used 50g of each metal and that resulted in lots of slag and about 55g of "useable" material.. The 'efficiency' wasnt too great but it was my first time and WORKED ..Some of the material is in 'mortar & pestle' pulverized state inside the plastic bag.I belive that this great waste was due to the very tiny amount of material handled) :

http://i242.photobucket.com/albums/ff176/tnitrato/P9060022.jpg

 

Unfortunatelly Im very busy, but I plan to repeat to got at least 200-500g of the funniest alloy ever created..eheh

Edited October 16, 2008 by Nitrato