Making Magnalium.

[Mephistos Minion]

I went and got a couple of cocktail shakers today. Melted some Al in a charcoal chimeny with hardware store briquette charcoal. Got a nice ingot. Gonna weigh out some Mg and Al tonight and make some MgAl (who'da thunk it?). Also melted a heap of scrap lead for shits and giggles. Gonna have a nice paperweight. Shall post some results when I get them.

 

EDIT: This evening's adventures:

 

I made up the furnace as such, but with chicken wire support:

 

http://img.photobucket.com/albums/v466/mephistosminion/ColdFurnace.jpg

 

http://img.photobucket.com/albums/v466/mephistosminion/ColdFurnaceII.jpg

 

http://img.photobucket.com/albums/v466/mephistosminion/ColdFurnaceWithCruciable.jpg

 

http://img.photobucket.com/albums/v466/mephistosminion/ColdFurnaceWithCruciablelidded.jpg

Edited October 17, 2008 by Mephistos Minion

[Mephistos Minion]

I got my 150g of Al and approx 155g Mg:

 

http://img.photobucket.com/albums/v466/mephistosminion/MdAndAl.jpg

 

I melted the Al down first:

 

http://img.photobucket.com/albums/v466/mephistosminion/BurnDatShit.jpg

 

http://img.photobucket.com/albums/v466/mephistosminion/AddingAl.jpg

 

http://img.photobucket.com/albums/v466/mephistosminion/AlMelt.jpg

 

I didn't get a pic of adding Mg, as it was too risky to tie up one hand with a camera.

 

The top of the melt was butt ugly:

 

http://img.photobucket.com/albums/v466/mephistosminion/Globs.jpg

 

But I got a few good flakes off:

 

http://img.photobucket.com/albums/v466/mephistosminion/Flakes.jpg

 

The ingot took some hammering on the base of inverted cruciable to get out, but here it is:

 

http://img.photobucket.com/albums/v466/mephistosminion/MgAlIngot.jpg

 

I'm gonna take to the top with a file to get the shit off, then smash it up, get some steel media for my mill and get powdering

 

PS: Anyone elses ingot smell like cat piss?

Edited October 17, 2008 by Mephistos Minion

[rocket]

PS: Anyone elses ingot smell like cat piss?

 

Yep especially when it gets wet, I believe its from magnesium nitride releasing ammonia.

[Mephistos Minion]

Whatever it is don't put your nose up to it and sniff...

[Bonny]

I'm gonna take to the top with a file to get the shit off, then smash it up, get some steel media for my mill and get powdering

 

PS: Anyone elses ingot smell like cat piss?

 

Be sure to save the crud you scrape off. After some crushing if needed, it works great in fountains, comets and even tossing it into a fire.

[FrankRizzo]

Very nice, Mephistos. Great idea with the chicken wire support collar as well. Tentacles and I noticed the smell only when we got the material wet. It's an ozone, old electric slot racecar, type smell.

 

Another addition to the technique that I don't think Tentacles or I have mentioned before is to set the extra metal on the coals around the crucible as the aluminum is melting. You'll have to watch to make sure it doesn't start melting, but it will effectively preheat the metals before putting them into the melt pool inside the crucible and save some time. A propane or MAPP torch will help here as well.

[Mephistos Minion]

Good idea. Though risking my Mg like that would freak me out. I only have 1.85kg left I reckon I'll make a 500g batch today, only problem is my scales only go to 200g (using reloading scales, super accurate, but low max) as my 500g ones are with a mate for weighing... uhh... flowers...

 

That and cutting Mg billets sucks, I ended up using a wood saw. Cut fast, didnt dull the hardened teeth much, and it gave me Mg filings for fountains too

[LBussy]

Hi guys, new here. Tentacles pointed me here regarding this thread and it's pretty interesting.

 

PS: Anyone elses ingot smell like cat piss?

... and ...

 

Yep especially when it gets wet, I believe its from magnesium nitride releasing ammonia.

Being new to the pyro world, I don't know enough about this to know if this is an issue. It would seem to me that having "other" chemicals present could be a concern if you are counting on just having MgAl. Is it, or am I paranoid?

Edited November 1, 2008 by LBussy

[tentacles]

LBussy: It hasn't been in our experience, and MgN or MgC (or stranges mixes thereof, which is probably what we get) should have no discernable effect on pyrotechnic devices. MgN *could* be slightly hazardous if combined damp with a chlorate, as there is a slight chance of ammonia forming which could produce ammonium chlorate (or at least a solution containing both ammonium and chlorate ions). However, this risk is present in any solution containing (untreated) Mg/MgAl) and chlorate.

 

Fact is, if you don't get it wet before processing it (at least brushing off the slag) then it won't have that smell. It behaves just like any commercial MgAl once crushed.

 

Don't believe ANYONE that tells you to put sulfur on a Mg fire to "put it out". This is a clear indication that they have not made MgAl.. Sulfur makes it burn more, and pretty well ruins the MgAl (Mg Sulfide, anyone?).

[tentacles]

xetap, Alan Yates is full of shit there - every single person I know who has actually made MgAl tried the sulfur thing, and very quicky was disabused of the notion. The fact is, no flux is required as long as you use a chimney (or similar). The chimney provides a very reducing environment at the top, so as long as it isn't overly windy, the MgAl won't have too much tendency to burn. The trick to keep it from burning while you are adding more material is to keep adding pieces to keep the temperature down. When you're done, cover it with airfloat charcoal, put a lid on it, and let it cool. I like to cool it quickly using a water bath for the crucible.

 

The taller your crucible is, as long as the top is near the same level (or below) as the top of the chimney, the less likely the contents are to burn at all. It would be neat if we could find SF6 in small pressurized bottles to use as a blanket.

[mormanman]

I use baking soda as my flux. It smells like poop but not like sulfur when you breathe the sulfur and it burns oh dear lord.

[FrankRizzo]

Mormanman,

 

None of the decomposition products of baking soda (CO2, Na2CO3, & water) are inert to magnesium or aluminum.

[FrankRizzo]

...why you need to make sure your media is rust-free if ball milling MgAl with old bearings.

 

[andyboy]

So, made my first batch of Magnalium today, noticed a few things that I wanted to point out for those wanting to try this.

 

1. Stir well once everything is melted. I didn't so I ended up with a fused Al and Mg lump, not the alloy.

2. When cooling with water, watch out for steam and drops from the fizzing, don't get any on the Magnalium. It will burn fierce.

3. Use powdered/ball-milled bentonite clay as a protective layer for the Magnalium, it will protect against moisture and oxygen.

4. If the Magnalium crackles when cooling it is good.

5. The Aluminium will probably have a lot more oxide then the Magnesium, account for this when weighing up your melt. Use large pieces of Aluminium if possible since there will be a lot less slag.

 

Anyhow, a few tips from a guy who's only done this once so I don't know how much it's worth. The Magnalium made was nice anyway (the Mg/Al in the box was given to me by Rooster a while ago I made the one in the crucible):

Edited January 17, 2009 by andyboy

[tentacles]

FrankRizzo, I, and Bonny all use airfloat charcoal to cover the molten MgAl once it's mixed up. It works well, as the C will burn and absorb much of the oxygen, protecting the alloy. The C is not detrimental to the final product, just remove the loose stuff and give it a decent brushing off.

[andyboy]

Is the layer on top of the crucible of magnalium you made, the clay?

 

How thick a layer of clay did you use, and how was it to clean from the alloy?

 

This looks to be a real good idea...

 

Thanks.

 

1,5 cm covering the crucible seemed to be enough and it was just poured of after cooling then I wire-brushed the remains from the alloy.

 

 

@tentacles, I did use airfloat in my first go (the one that failed because I didn't mix it, just banged on the side) but it burned of fairly fast so when I remelted the MgAl I went with the bentonite instead because that's what I had nearby. I noticed that it worked well so I wanted people to know it might be an option aswell.

Edited January 18, 2009 by andyboy

[tentacles]

No reason dry bentonite shouldn't work - but be careful because even "dry" bentonite can hold on to some water. It would be best to oven dry the bentonite prior to using it this way, just for safety's sake.

 

I've found also that you've gotta be sure the stuff is well stirred or you'll find little bits of this and that metal in it. Out of curiousity, how much airfloat did you put on top, and did you cover the crucible after putting the charcoal on?

[andyboy]

I put a hand-full of airfloat on top, tried covering but it was still burning (small white flashes along with the yellow) but I just let it sit until it was cool enough to get out of the crucible. That's when I noticed it was not alloyed so I melted it down again, stirred and saw that there where no white flashes this time, poured on the bentonite for good measures and let it cool down. This time it cracked from a light hammer blow to the bottom of the crucible.

[Yankie]

Where can I find info about milling MgAl? I have heard many different methods, some describe milling it and then letting the jar sit overnight before opening, others suggest opening it every half an hour.

[andyboy]

I would suggest opening it once every 10 minutes since it breaks so easy. It would take less time for it to have a lot more surface area then when milling Al so all available oxygen would be consumed rather fast. I think! (not sure) that this would happen exponentially, after 10 minutes the surface area would have grown 10 fold and after 10 minutes it's 10 fold again (so 100 times the surface area that you started with after 20 minutes).

[tentacles]

As long as your jar isn't vacuum-tight, as the oxygen inside is eaten up, more air will be pulled into the jar, at least until the atmosphere inside is 100% inert (N, CO2). So to at least some degree, the reaction will happen regardless - we've milled for as long as 5 hours at a time, I think. That was with an 8" jar / SS media and I think 3 lbs of MgAl. FrankRizzo may remember the specifics a bit better than me. We've milled several batches for ~3 hours at a time with no ill results - absolutely no heating up when opening the jar, or when the media's sifted out.

 

I think the pyrophoricity needs the MgAl to be milled to a very very small size indeed - the last batch we did is super hot stuff. It's been speculated that the accidents that have happened were likely caused by media sparking while there was a cascade of finely divided metal falling through the air. I'd suggest being extremely careful when emptying the jar, don't drop the media from any kind of height if you can avoid it. MgAl WILL spark on a hard enough impact - you can actually light it on fire (briefly) with a hammer if the circumstances are wrong. Most people's media won't have the mass needed to do this, even to tiny bits of the metal.

[andyboy]

We've milled several batches for ~3 hours at a time with no ill results - absolutely no heating up when opening the jar, or when the media's sifted out.

 

Sounds good, of to buy some SS-balls.

[Yankie]

Ok, I may drill a small hole, very small, in the lid of the jar, and cover it with a peice of cofee filter. Where can you get SS ball bearings cheap?

[tentacles]

Ok, I may drill a small hole, very small, in the lid of the jar, and cover it with a peice of cofee filter. Where can you get SS ball bearings cheap?

 

LOL! Cheap, if only we knew! Regular ball bearings will work fine, or chunks of SS rod. FrankRizzo knows of a cheap source of mining milling media, they're steel balls made for milling ore and such, they would work for this although I don't think I'd be comfortable with it - if there's any rust you could get a thermite reaction on impact (IE pouring it out!).

 

Steel ball bearings would work, as they've got a chrome coating on them. Just keep them from rusting and you'll be fine.

[andyboy]

I've got a friend that works on SKF: http://www.skf.com/portal/skf/home

 

:D :D