making magnalium without a gasburner

[Polumna]

hi ddudes

 

i´m back from work now.

 

I have got one question: is it possible to melt magnesium and aluminium in a can over a coal-fire to make a mg-al alloy???

 

i have heard from Magnalium that it is very brittle and easy to grind to very, vrery

high mesh-sizes by hand.

 

 

but i can´t get my hands on a propane-burner, so that is the problem

 

thanks for all ur advices, polumna

[weknowpyro]

I expect aslong as you got your coal fire really hot it is theoretically possible because Mg has a melting point of 650 degree's centigrade and Al has a melting point of 660 degrees centigrade. So aslong as you stoke your fire and pile on the coal it might just work.

Then once these are both liquids you can just follow the steps from any of the tutorials on the web.

[hashashan]

ill use this to ask a mgnalium question

i have a problem to get MG blocks ... only powder .. im afraid itll ignite. anyonw tried to use powdered magnesium?

[Polumna]

no,

 

 

if magnesiumpowder is used, the magnesium would react easier with oxygen, the magnesiumpowder would catch fire very easy.

 

 

why have u got a problem with finding magnesium in block form???

 

get a sharpener(that was my first source of magnesium), a firestarter or a node or a VW_Engine Block.

 

I have no problems wwith magnesium anymore.

 

I HAVE GOT 30 KILOS OF PURE MAGNESIUM

[Polumna]

hi

 

 

i would try to use a hand-usable fan for the coal fire (extrem heat production)

 

i´m using briquettes for forging,the flames are pink and i get steel to burn with this coal.

 

I try to make Mg/Al mext weekend, because i have woodworking now

 

PS: How much time would it take to grind MgAl in a Mortar & Pestle until it reaches 800-1000 mesh???

 

polumna

[leosedf]

It works as long as you have an air supply under the charcoal (a small pipe or something similar).

It worked really fine for me, but you have to be sure about your crucible because mine was too thin and if it gets destroyed you may have molten metal all over the place (plus the dangers of magnesium when burning). I did it outside so no harm was done.

[Umphrey]

MgAl can easily be made without a gas burner, I have done so numerous times. It is quite easy to get a well ventilated anthracite coal fire up to that temperature, actually much higher, I have sucessfully melted small quantities of copper pipe with it.

 

The key is adequite airflow to keep the flames white hot. It won't work using an under aerated fire, there are two simple ways to insure an airflow, one is to have the fire elevated so that air can flow under it, another is to place a long steel pipe connected to an air compressor in the center of the fire.

 

I have had much success simply elevating the fire, to do this, I use a 3x3 foot section of iron fencing held off the ground by 4 metal posts. In the center of the fencing I place a little over ten shovelfulls of anthracite coal. This will take about a half hour or more to get burning hot enough to place your crucible on it. Depending on how much MgAl you're making, you may have to add a couple more shovels worth while it's going to keep the temperature up. It works best when it's windy, or if it's not, you can set an electric fan up near the fire, angled upwards. Metal bladed fans work best, I've had a plastic fan melt on me.

 

 

Getting the anthracite to take fire can be somewhat of a problem. There are two ways around this, one is using a bag of the cheapest briquette charcoal to get it going, another, which I prefer, is to use a propane blowtorch to start the coal. Harborfreight sells an excellent one: http://www.harborfreight.com/cpi/ctaf/disp...temnumber=91033 It takes only about ~10 minutes of torching the center of the coal pile to get the fire roaring.

 

 

This blowtorch incidently also works great for producing SMALL(250g or less)quantities of MgAl all on it's own, just have your crucible up on some bricks and let the torch flame envelop it. I lightly tilt the crucible back and forth with a pair of pliers to mix and verify when it's all liquid.

 

Finally, selecting a proper crucible:

 

I have found stainless steel pots with a lid work as an excellent crucible, the lid is tight enough to seal the air off the magnesium, preventing it from erupting into flame, but loose enough to allow any gases to escape. You can slide the lid off an inch or two to check on it, but place it back on as soon as possible, or the Mg will be burning.

I use something very similar to this: http://www.all-creatures.org/recipes/images/u-pot-sslg.jpg

 

 

 

A word on safety, DO NOT use cookie tins, or any thin metal container, IT WILL FAIL, spilling hot flaming molten magnalium everywhere. Be sure to wear proper safety gear, heavy gloves, thick clothing, but do not wear so much that it bogs you down, or makes it difficult to maneuver. No matter what you're wearing, you're screwed if molten metal spills on you. A long pair of tongs or pliers is required for manipulating the crucible. Do not use water to put out a magnesium fire. Common sense and taking your time are the best way to remain uninjured.

 

 

 

PS: How much time would it take to grind MgAl in a Mortar & Pestle until it reaches 800-1000 mesh???

 

While brittle, I doubt very much you could grind it much past 200 mesh with a mortar and pestle, a ball mill will make it extremely fine--to the texture of powderd sugar after a week or so. For the first couple days, It's important to open the ball mill every few hours, to allow it to gain an oxidized coating, or else it can become pyrophoric, that is to say, it ignites on contact with air. After all this is done, I place the container outside and just barely open the lid, letting it sit for one hour, to oxidize the rest of the way. When you're opening the ball mill to let it oxidize you can also check the particle size, it's pretty easy to aquire a collection of different meshes.

[Polumna]

hi dudes,

 

thanks for all your great advices, they have helped me much.

 

I´m a very careful person and i do this outside.

 

I get around 10kilos of aluminium from work now and first of all i´ll start with small amounts

like 50 gramms(melting magnesium and aluminium).

 

Safety gear shouldn´t be a problem since I have a pair of safety-glasses, hand-shoes,

and very good sunglasses, in the case that the aluminium or magnesium would caught fire

 

 

The scarriest part of the process for me is that i´m afraid that the magnalium would splash every-where and caught fire whem i´m stirring the melting magnalium

 

 

Polumna

[Umphrey]

If you're not using a salt flux, I would strongly advise against stirring magnalium in an open crucible. It's much better to use a crucible with a lid, to keep the air out. Simply use a pair of tongs or pliers to gently rock the crucible, you'll feel when it's all melted. Tilting the crucible in a circular motion is sufficient to mix them--stirring is unnecessary. For larger quantities, place a handful of stainless steel ball bearings in the vessel, then tilting it to fully mix will work perfectly. Just leave the ball bearings in it while it cools, they'll be easily removed by hammering the magnalium into smaller pieces.

[Bonny]

I've made a few small (200-400g) batches of magnalium using a homemade wood stove I built to heat my garage in winter. I load the stove with wood all around the stainless steel crucible (bowl) and place a fan in front of the (open) stove door. The stove is outside for this operation.The wood I use is Tamarack (larch tree) and burns very hot. Takes awhile to melt, but works fine. I have poured it onto a pc. of angle iron, or simply let it cool and then broke it out of the bowl.

 

I did make it once with a tin soup can, but the sides burnt through and I lost quite a bit...

[mormanman]

Ok I have questions also. Where might I find anthracite coal? I looked on wikipedia and there was almost nothing on where to find it. And what is the ratio for MgAl?

[Mumbles]

The ratio is 50:50 by weight.

 

As for anthracite coal, try a coal mine, or a coal burning plant. There is a plant like that here, and they drop coal everywhere, so it's not too hard to come by.

[mormanman]

Ok well I'll get on that when ever and tell you guys how it goes. If you care.

[Umphrey]

Where might I find anthracite coal? I looked on wikipedia and there was almost nothing on where to find it. And what is the ratio for MgAl?

Look in the yellow pages for coal dealers. Anthracite Coal will cost about 130 to 200 dollars per ton. Some places will sell it in 80 pound sacks, but it is less cost effective to purchase this way.

Don't be tempted by the cheaper price of bituminous coal, it will make a fire that produces noxious fumes and it won't burn nearly as hot.

 

Also, you may be able to get away with using charcoal, but you'll need to use several bags worth. You'll need a fire with lots of air circulation, a BBQ pit will not get hot enough.

 

The ratio of typical MgAl is 50:50, although I have also made 60:40 and 40:60. 50:50 is by far the most common and most brittle.

 

Now if you're making small quantities of MgAl, forget about using an open crucible or stirring. Don't mess with salt melts or throwing sulfur on it. I use a stainless steel salt/pepper shaker for small batches. It has several small holes in the lid to allow gases to vent, but small enough to prevent air from getting in and reacting. After the stainless steel is glowing red, the MgAl will be molten inside, to ensure a good alloy I gently pick it up with a pair of pliers and tilt it back and forth so as to mix it. I place it back on the fire for a few minutes and repeat the mixing procedure. When it is all molten(You can feel this by manipulating with the pliers--don't take the lid off.) set the container aside somewhere to cool. After it has thoroughly cooled extracting the MgAl is quite easy, several knocks with a hammer on the container will eject a perfect cylinder of magnalium.

 

The shakers can be reused several times. I buy them at walmart for 4.99 per set.

[Bonny]

Don't mess with salt melts or throwing sulfur on it. I use a stainless steel salt/pepper shaker for small batches. It has several small holes in the lid to allow gases to vent, but small enough to prevent air from getting in and reacting. After the stainless steel is glowing red, the MgAl will be molten inside, to ensure a good alloy I gently pick it up with a pair of pliers and tilt it back and forth so as to mix it. I place it back on the fire for a few minutes and repeat the mixing procedure. When it is all molten(You can feel this by manipulating with the pliers--don't take the lid off.) set the container aside somewhere to cool. After it has thoroughly cooled extracting the MgAl is quite easy, several knocks with a hammer on the container will eject a perfect cylinder of magnalium.

 

The shakers can be reused several times. I buy them at walmart for 4.99 per set.

I also found adding any fluxes (sulfur,salts) just made a mess.Your tools and technique sound great, I'll try that next time,need more Mg first though...

 

Do you guys have tamarack trees in US? Never tried in BP but plenty hot for melting Al etc... and bonus is the wood (and smoke) smells great too.

[FrankRizzo]

You guys are making the process *WAY* too hard. All you need is charcoal briquettes (or lump), a "chimney" charcoal starter, and a few soup cans for cruicibles. Fill the chimney starter about half-way with charcoal, place the can inside on top, then fill around the can with charcoal to the top. Place a few pieces of waded-up paper beneath the charcoal starter to get the charcoal lit, put a few pieces of your aluminum in the can, and wait for it to melt. Once you've got a nice pool of aluminum on the bottom of the can, the conduction will be much better, and you can then add the rest of your aluminum to be melted. Once all of your aluminum has melted, add the magnesium and stir. The reducing atmosphere of the burning charcoal surrounding the tin can crucible seems to keep the alloy from burning too readily although you might get a few little hot-spots. After both metals have been mixed together, cover the surface of the molten metal with charcoal dust, remove it from the fire, and place it in a shallow bucket of cold water to cool below the ignition temperature rapidly.

 

In just a few hrs (and a few beers ) Tentacles and I made over 5.5lbs of magnalium yesterday.

 

Here's a photo of a chimney starter; they're ~$12 at WalMart.

 

http://www.4electronicwarehouse.com/content/weber/cstarter.jpg

[justanotherpyro]

I made my MgAl using a coffee can. It does work but more care is needed to keep it from burning through the side. My furnace was an iron tire rim and I used briquettes and natural wood charcoal as my fuel. I did have a blow out through the side of the crucible on a previous try because I had the aircompressor concentrated on the same spot for to long. Ball milling marble sized chunks down to ~600 mesh is fairly easy just be sure to open the milling jar often enough during milling to expose the contents to air so you don't get spontaneous ignition.

[tentacles]

Just a bit to add..

 

We have found that it works best if you stir constantly, this will help prevent burn-through of your soup can, and tell you when all the chunks are melted.

 

We did try a blower under the "chimney" and found that it can very easily get much too hot for the can. If you want to use one, do so sparingly and stir constantly.

 

We do cover the cooling can while in the bucket of water with a firebrick to keep water from splashing inside, and to prevent burning. We sit the can on a firebrick in the water to keep it from melting the bucket.

 

I suggest adding the metal a piece at a time to the mix as it melts, this will go a long way to prevent the metal reaching ignition temperature. And it will help keep the can from melting through.

 

We do keep meaning to take pictures of the process.

 

Here's a picture of a 2 lb chunk:

 

http://www.apcforum.net/files/DCP_2410.JPG

[qwezxc12]

Does the MgAl contract enough during cooling to readily come out of the can crucible? Or do you have to cut the can away? Also, is that slag in the bottom of the ingot, or do you dust the can with some sort of flux to prevent the MGAl from adhering?

 

Inquiring minds want to know

 

Thx.

[mormanman]

You guys are making the process *WAY* too hard. All you need is charcoal briquettes (or lump), a "chimney" charcoal starter, and a few soup cans for cruicibles. Fill the chimney starter about half-way with charcoal, place the can inside on top, then fill around the can with charcoal to the top. Place a few pieces of waded-up paper beneath the charcoal starter to get the charcoal lit, put a few pieces of your aluminum in the can, and wait for it to melt. Once you've got a nice pool of aluminum on the bottom of the can, the conduction will be much better, and you can then add the rest of your aluminum to be melted. Once all of your aluminum has melted, add the magnesium and stir. The reducing atmosphere of the burning charcoal surrounding the tin can crucible seems to keep the alloy from burning too readily although you might get a few little hot-spots. After both metals have been mixed together, cover the surface of the molten metal with charcoal dust, remove it from the fire, and place it in a shallow bucket of cold water to cool below the ignition temperature rapidly.

 

In just a few hrs (and a few beers ) Tentacles and I made over 5.5lbs of magnalium yesterday.

 

Here's a photo of a chimney starter; they're ~$12 at WalMart.

 

http://www.4electronicwarehouse.com/content/weber/cstarter.jpg

I'll try this one. I looks easier. But I'm going to have to make a make shift "chimney starter."

[FrankRizzo]

Does the MgAl contract enough during cooling to readily come out of the can crucible? Or do you have to cut the can away? Also, is that slag in the bottom of the ingot, or do you dust the can with some sort of flux to prevent the MGAl from adhering?

 

Inquiring minds want to know 

 

Thx.

The MgAl does constrict slightly while cooling, but certainly not enough to clear the molded-in ridges that are formed by the can structure; we have to cut away the can. If you had a cast-iron or graphite crucible, the ingot should shrink away from the walls enough to just pop out. Since cans are basically free, they're the obvious choice for a disposable crucible (and can still be recycled after you're done).

 

The bit of discoloration that you see on the bottom of that ingot is probably a little bit of the burnt "freshness liner" (plastic) that coated the inside of that soup can. It's ash, and can easily be wire-brushed off.

[Bonny]

Sorry to drag up an old topic... Has anyone ever made MgAl in steel muffin tins? My nieghbor is a blacksmith and has a small forge. I was hoping to make a nice batch of magnalium using muffin tins as the crucible. I shouldn't have to worry too much about overheating and melting the crucibles as I think the forge temp can be controlled. This would (hopefully) yield nice manageable ingots of MgAl.

[Bonny]

I made some MgAl today and am having some problems. The first puck I made shatters easily, nice and clean and shiny. The second puck is hard as hell to break and when it does it has a crystalline structure rather than being shiny and sharp edged.Anybody else evr have this happen? I'm wondering if the big pc of (cast) Al I used was loaded with zinc or some other shit alloy maybe white metal? It was an end cap from an air cylinder.

Anyway I'll test some of the powder produced when trying to break it to see if it usable as a metal fuel in a star comp.

 

As a last resort maybe I should re-melt it with an equal or excess weight of (known) Al and Mg?

[FrankRizzo]

Tentacles and I had similar problems with the material near the edges of the tin can crucibles we were using due to incomplete mixing of the magnesium with the molten aluminum. Make sure that you stir the melt sufficiently.

[Bonny]

Tentacles and I had similar problems with the material near the edges of the tin can crucibles we were using due to incomplete mixing of the magnesium with the molten aluminum. Make sure that you stir the melt sufficiently.

I did stir the mix, but maybe not enough. When I get some more time (and Mg) I may re-melt to try and salvage the material.

The air cylinder cap did seem a bit heavy, though it drilled and filed like Al, which is why I suspect it may have been an alloy of some kind.