Aluminum melting

[unfy]

Sooooooo

I've got a garbage can full of root beer, pepsi, etc cans.  I had talked about the electric furnace a few times before... but that's kind of on hold due to situations etc.  I still wanna do things with it, but the full can is taking up too much room, maybe if I made some quick ingots...

Decided to go ahead and "build" this: (punching holes in coffee cans dont count as building...)

http://www.instructables.com/id/Build-a-foundry-and-sand-cast-aluminum/

Built as described (see first pic).

Went through a bunch of cans, and I know cans aint much... but was starting to get a little more than curious / worried ... especially when the entire "crucible" (read: bean can) seemed to be filled with nothing but dross.

Took it apart and I found where all the aluminum went (see next two pics).

So, for a first attempt, I'd be willing to call it a 'partial success'.

I'll try again - with either not pressing down on the cats cans at all, or possibly using a 2" diameter black nipple as the crucible.


edited for typo

[shooter]

 how many cans did you melt? and ounces of good aluminum?

   I thought about using broken up transmissions?

[unfy]

How many cans ? No clue.  This was a first run and just trying to actually pour an ingot.

Didn't get there.

I have bean can (ok, soup can, whatever) that has probably a half inch or so of aluminum in the bottom of it, and then I have all that seeped out into the bottom of the air chamber coffee can.  I'll.... take a look at getting the aluminum out of the bottom of the coffee can in a bit since there's some questions.

Here's a fella that does a 55 gallon bag of crushed cans:



He guesses at the end 50/50.  There are complaints in the comments, as expected.  The top comment suggests about a 30% loss instead.



This guy has a much larger setup, he melted the head of a car in a relatively short amount of time (25-30min?).




It was interesting to do my first melt of something other than lead.  I'm sad that it didn't go as planned but it was still a learning experience.

A 2 inch diameter nipple doesn't really seem like an ideal crucible.   But the idea that it came from was this video:



Which seems to be a great video IMHO (and I have all the materials to build one of those if I wanted heh).

Anyway, 2" diameter means I'll have to fold each can as i put it into the crucible.  It also means that muffin tin ingots are out of the question.

I've got a Lee ingot mold for lead, I'll check if it's steel or not.  I'll also grab some 1-1/2 or something PVC to make some positives to push into sand (barring terminology).


I will LOL for a moment - the stuff in the bottom of the air chamber coffee can is so silly light when used to working with lead .

[unfy]

Here's a couple more pics of the inside of the coffee can (below).

Seems to fluctuate a bit from 'none' to an inch and a quarter.  If I had to guess at average thickness, 3/4" or maybe 5/8".  It's a fair amount of fairly clean looking aluminum, which makes sense if it was leaking out of the bottom or side of the crucible.

I tried to gently hammer it out, but didn't have much luck without damaging the chamber too much.  Looks like I'll have to destroy the chamber to get it out .  I sadly don't have spare coffee cans lying around... and the 2 cans I used in this video were bought new (with coffee sitting in some bags in kitchen).  Guess I'll be buying yet MORE cheap coffee, sigh.

Oh!  Annnnd be aware - beer / soda cans aren't "just aluminum", they're an alloy.  Wiki says 92-97% aluminum. 

[unfy]

I guess it wouldn't be an unfy post without some talk about safety.

Don't use anything galvanized when working with melting aluminum.  You'll burn off the galvanization (zinc) which produces nasty fumes that will kill you.


This means no plated sheet metal, no plated hardware, don't use air ducting, anything that says the word zinc, etc. 

Coffee cans yes. Paint cans yes.  Food cans yes. Things that are 'weldable' yes.  Things that are 'stainless' yes.

I picked up the $40 respirator / air filter thing from hardware store.  Go ahead and buy the nicer ones that can block laquer and other things like that.  You ARE spending money for your own health here.  And I will gladly say that there was a huge difference in the smell of things etc after I took my mask off when investigating what was going on (so yes, it was doing its job wonderfully).  Also, it's nice to not get a lung full of hot air when the wind shifts or you're over the furnace.

Although I didn't feel it was fully necessary, I was wearing a welder's / leather bib.

As mentioned in the "instructable", don't stick your hot tongs down into the charcoal bag to grab another briquette to put into the fire chamber.  Them tongs are real hot and might ignite something.  I dumped out a bunch of briquettes onto the ground and just picked them up from there.  Was also easier instead of fumbling with them inside the bag (and means you didn't have possibly wet tongs near molten metal too).

All of my cans are dry but do be aware of the tinsel fairy and try to avoid it.

Although I had no spills, and such - the leaking crucible did mean I put a burnt circle in the grass.  This was unexpected and unfortunate.  Be aware and careful!

[ILoveCats]

Sorry if I missed this but...  What's the objective actually?  I mean other than just melting stuff.  Isn't it more cost effective to take the cans to Scrappy's to sell em for a few cents a pound?

[unfy]

Canpac here in Omaha looks to be $0.25 a pound, and the standard web coupon gets it to $0.30 a pound.

I might have ... 30lbs ? I dunno.  That's all of $9.

If it's 50/50, then 15lbs of ingots looks to go for about $50-$60 plus shipping (ebay, rotometals, etc).

addenum:

Ok, and lets add say $12 in charcoal to do all the melting (truly dunno how much I'll need, btw, this was a 2 bag guess).  Also get experience in the whole process and learn something new

As a cute side note - the first time I melted lead for making ingots, the pot I used burned through just like this crucible did hehe

[Mali]

Unfy,
I haven't had time to try this approach, but this video seems to make a pretty good crucible and foundry that would work better for you:


The surprise of what he creates from the melted aluminum was so appropriate.

The video for for actually melting the cans (10-12 cans/min) and creating aluminum ingots is here:


He found 38-45 cans creates 1lb of aluminum to be sold or used for casting.

[Phantom]

Is it just me ....or

when Unfy posts one of these and then talks about safety. 

Like me does everyone else look around for Minions ?   

[Mali]

Is it just me ....or

when Unfy posts one of these and then talks about safety. 

Like me does everyone else look around for Minions ?   

No, I agree. Unfy talking safety does make me wonder sometimes.

[unfy]

Unfy,
I haven't had time to try this approach, but this video seems to make a pretty good crucible and foundry that would work better for you:


... snip ...

He found 38-45 cans creates 1lb of aluminum to be sold or used for casting.

38-45 cans seems about right going with the 30-50% loss number.

Fire extinguishers were on the list of possible crucibles.

Stainless cook wear is apparently on the list as well.

Car exhaust is another fine possibility that I've not dug into much (mostly due to how do I easily cap one end ?).

Fence posts are a no no (galvanized typically).

What I'll be trying next is one of the blue 14oz propane bottles for torches.  Make sure it's empty.  Remove the valve while it's underwater.  Make sure it gets filled with water so that there can be no gas in it etc.  Free to cut with grinder / hacksaw.

Why propane bottle ? I have one.  It should fit nicely in the fire chamber.  Should be big enough for soda cans.  It's not as thick walled as a black iron pipe nipple.   And looking at pictures, it's not as thick as a fire extinguisher either.  But - I have a spare propane bottle damnit .

The coffee cans as air chamber and fire chamber survived with no problems by the way.

A lot of this would be solved with a welder and stock metals, which I don't have access to.

Concerning furnaces & such - there are ALOT of videos out there.  There are ALOT of ideas.  The ideas about the different insulation is a mix of what they had available, what they wanted to try, and cost stuffs.  The different refactories also all have different service lifetimes (plaster of paris is on the shorter end of that list, by the way).

A charcoal base is cheap to build and cheap to fuel for quick one offs.  It produces the most ash, which then leads to the most dross / slag / whatever you wanna call it.  The amount of air movement also increases surface oxidation of the molten aluminum.

Propane torch + plaster or some other refactory can be built cheaply as well ($60 should get you something decent, $30 is prolly bare bones).  I will be building one of these eventually, just for the experience of it.  Also seems like less of a hassle than charcoal to use.  Oh, it's cleaner than charcoal (concerning crap in the aluminum etc).

Electric - initial heat / warm up takes longer.  There's not a huge amount of air flow so there's less oxidation.  Electricity is cheap.  The build is more complicated, and more costly as well.  You're tied to a generator or wall outlet.

Is it just me ....or

when Unfy posts one of these and then talks about safety. 

Like me does everyone else look around for Minions ?   

No, I agree. Unfy talking safety does make me wonder sometimes.

Bite me, you two

I know y'all just giving me a hard time, but the insistence on safety is prolly why I can post here about some the weirder things I do


But, at any rate, after I get a few melts down (and there is no snow on the ground) - I'd be willing to show and tell with folks so they can try it out as well.

If I build something that takes a propane torch, I'll post about it as well.

[unfy]

Here's the crucible, and the bit of stuff that was in the bottom after cutting it out, etc.  There's still a little bit of steel on the puck on the sides.

The bottom didn't leak, but the sides blew out. 

The big obvious hole in the side you see in the first couple pics are from when I was actually hitting the side of if afterwards to just clean it up some. It acts just like a can that you recover from a campfire.

The bottom wasn't in too bad of shape compared to the rest of the can.

The puck I'll either keep as a momento or clean up the bit of steel that's still on the sides of it... and re-melt later.  It's a hefty little puck.  Dunno if that's a good thing or bad, but I swear I see plenty of good metal in it.

[Mali]

I know y'all just giving me a hard time, but the insistence on safety is prolly why I can post here about some the weirder things I do

And it is the reason I pay attention to what you talk about.  Experimenting is great as long as you can live to tell about it.

Some of the greatest disasters have started out with "Hey y'all watch this!" others with "Hold muh beer."

[unfy]

Cut up the air chamber to get out the glob of stuff in it.

1.41 pounds of relatively clean looking aluminum came out of the bottom of the coffee can.

See pictures.  Pencil for scale.

[Mali]

How heavy is it and how many cans did it take to get this?

[Phantom]

Quote from: Phantom on September 14, 2015, 02:32:46 PMIs it just me ....or when Unfy posts one of these and then talks about safety.  Like me does everyone else look around for Minions ?    Quote from: Mali on September 14, 2015, 03:48:23 PMNo, I agree. Unfy talking safety does make me wonder sometimes. Bite me, you two I know y'all just giving me a hard time, but the insistence on safety is prolly why I can post here about some the weirder things I do

It's a Dirty Job.........but someone has to poke you from time to time 

[unfy]

It was time to try again.

Went to thrift store, picked up a couple steel / stainless things to make crucible out of.  Also cut a 14oz propane tank in half.

Went through two crucibles and they both had blow outs.

No, I'm not jabbing them with anything.

No, I didn't press the cans down into the pot.

I'm a bit at a loss.  I *might* try again tomorrow, I dunno.  Getting a bit discouraged as to what I am doing wrong.

addenum

Off to the hardware store to build the 'king of random' furnace.  Maybe the melts are taking too long which is causing problems.

[Mali]

Went through two crucibles and they both had blow outs.

No, I'm not jabbing them with anything.

No, I didn't press the cans down into the pot.

Perhaps the heat isn't high enough to quickly melt the metal so you are keeping it at heat for too long? Or maybe the crucibles are too thin for the heat you are using?

[unfy]

Perhaps the heat isn't high enough to quickly melt the metal so you are keeping it at heat for too long? Or maybe the crucibles are too thin for the heat you are using?

Too thin is a possibility, but I don't think so.  The bean can lasted a little while, the first crucible today lasted a good 45-50min.

But, 50min ... that's like, 2-3 times too long compared to videos, hence thinking that maybe it's too long / need to insulate / whatever.  With the crucible being in direct contact with the coals, they prolly take a lot of abuse, while the aluminum is slightly insulated.

Also, I never really got to the point of where cans would just disappear directly into the Al pile, even with a decently melted pot cleaned of dross, it was still kinda "meh".  So I'm really thinking a 'better' furnace would really help out a lot.


The King of Random / Plaster of Paris bucket furnace - he got all his parts from Home Depot btw

I had stopped at menards to pick up some stuff (it's by work, etc) ... the metal pail they have is 12qt not 10qt.  Went ahead and grabbed the pail, 1x12 black iron pipe nipple (it'll be directly in heat, so no galvanized plz), pvc & adapter, play sand, u-bolts.  Also nabbed a 3" pvc coupler for the lid hole (instead of drilling it, although I believe I have a 3" hole saw).  Didn't see any 2.5qt buckets. The Bellevue Menards also doesn't appear to carry the 25 lb bags of PoP.  Weird.  Site and App says they do, but it aint there.

Went to Home Depot in Papillion.  Wandered around a bit, found some buckety things, and noticed a 2.5qt blue bucket.  Kinda near it, found the 10qt steel pail and grabbed it as well (will return the 12qt). Wandered around some more, looking for PoP (and maybe 'fire clay').  Didn't have much luck, pulled up the App.  Stuck 'plaster of paris' into it, and clicked on the 25lb bag.

What were the other suggested items from the app ?

The 2.5qt bucket.
The 5qt wide mouth bucket.
4" U-bolts
Play Sand
etc

I actually started laughing in the store.

Papillion had 2 bags of PoP, I bought one. They didn't have the 5qt wide mouth bucket.  I'll just use some kind of substitute.

I am *really* tired (been up 20hrs or so)... gonna prolly just do the furnace build tomorrow while at work casting bullets and try aluminum again sometime throughout the week or next weekend.

I have a SS cup thing that is a bit on the skinny side of things but has a decent thickness, but it might work as a crucible.  A second thrift store hunt netted some pewter for lead alloy, but no other crucible possibilities.

I'll prolly also grab another bean / soup can as well.

Walmart did have an 18oz SS camping cup that was fairly wide mouthed but not very tall.


edited to fix some typos ... also, I appear to not have a 1-3/8 hole saw so will add that to my shopping list tomorrow

[unfy]

So.... the build has started, and has been taking far longer than expected... mostly because of me and not having the tool(s) I thought I did.

Anyway...

10qt pail, blue bucket.  Used sand as my filler, it was heavy enough it didn't try to float as much as video's did.

I did the 21/21/15 mix as suggested in King of Random's youtube video - but my play sand was already wet so.... I ended up adding some extra plaster to help thicken it a bit more / quicker.

The mix was in a 5 gal bucket to begin with, after I had all the chunks broken up and was mixing it for a bit, poured it into the 10qt pail.  It was taking a long time to begin to set, so I kept mixing it.  From a tactile view, this seems really important - continuing to mix it up until a bit before it's ready to set helps to keep the plaster / sand mixture more homogeneous.   Otherwise, the sand will just settle at the bottom.

The lid was a 10" plant / pot thing from garden section of menards.  Cost a buck.  The middle was ... I believe a 1 liter diet pepsi bottle.  The middle section of this bottle is 3" in diameter, making it good as a middle form.  Used some packing tape along the inside to tape it down (stop leaks, keep it in place, etc).  The bottle is flimsy, so heads up on shape.

I mixed this as 10/10/6.5 since the sand was already wet.  I ended up with about a half gallon left over.  I wonder if this means my lid isn't as thick as the videos or what.  Then again, my bucket is also fuller than the videos.  Shrug.  It set quicker due to less water, which is nice because mixing it in the bucket before pouring it into the form is easier than trying to keep it agitated in the form.  The nuts in the U bolts are holding the bars about in the middle of the plaster.  I tried to keep the u bolts lifted so the bare metal wasn't exposed on the bottom of the lid.  We'll see how well I did after a while .

It's about time to remove the bucket and maybe drill the hole.


addenum: the pepsi bottle was used instead of the 3" coupling because the coupling has an OD of like 4".