Al melts @ 1220 F. Good job. I did this once, with my Dad's brand new grill and a shop vac/blower. Bad idea, since the grill was made of thick cast aluminum. Not only did I blast furnace a hole in the back of the grill, I set the back yard on fire to boot. However, it did guide me towards a career. I have been a firefighter now for 28 years. I fixed Dad's grill with a piece of metal road sign and some self-tapping screws. He was still awful pissed off at me though. There is just no pleasing some guys. Cheers from Texas.
Nice try ;) I've worked in aluminium casting industry, it's pretty fun^^. For safety, I strongly recommend to dry the cans before melting them. a single drop of liquid in the crucible can make it explode (it happens at my work once in a 40 tons furnace, over 6 months of maintenance stop for the furnace, the loading machine and some equiments around. 14 years after the accident, you can see some marks on the walls and the ceiling of the foundry, but fortunately no one had been injured).
mrhomescientist I am a maintenance tech, so I don't work directly in the process. heavy industries like this are heaven for techs, even with the risks. these accidents are very rare, they happen usually when somebody unaware of safety directives throw an empty can, but still wet, into the dried scraps boxes just before the loading. If you like big machines and technologies and if you have the chance to visit an aluminium industry plant, take it, you can learn a lot^^
Learned that one the relatively hard way. I have a tiny bucket forge and was melting a can that still had some soda in it. It was cool at first, until a tiny bit of the hot liquid landed on my forearm. Never again.
I've just gotten interested into melting metals and making ingots and a lot of the videos I've seen have made it look really hard. This video on the other hand, made it look very easy and actually possible, so thanks!
Very cool crystals on the aluminum. I really like your videos. I hate all the people worried about safety... Just a bunch of unadventurous people scared of their own shadow!
In my experience if you sorta skim off that slag periodically you get a better ingot at the end, I used a steel spoon for that. However, that stuff is protecting the rest of the molten metal from oxidation, so leave a layer on there until it's time to pour. Fortunately it floats. I NEVER do this because I HATE safety dinks, but brother, you gotta wear some shoes. Sometimes it pops and little (or not so little) bits of molten aluminum go flying, and if that hits bare skin you'll be very unhappy. And sometimes you dont see where the drops land, and then you step on them in the grass, and well, it hurts. Ask me how I know this.
If you use the metal tubing and the silicone hoses and hose clamps from a front mount inter-cooler setup for a turbo car as the pipping it will be a lot more secured to the hair dryer, and a lot more reliable. Other than that good idea, it seems to work really well. As for what shoes to wear, Mack Boots are awesome, and I've had the pair I'm wearing now since 2008. They still have plenty of rubber grip left, nearly like new actually, and I did security in them for 5 years. They breath very good, and I never get sweaty white spots on my feet from them, but as soon as I wear cheap sneakers for a day it's another story. I love my Mack Boots. Totally worth the $140au I paid for them.
Technically it's dross, aluminum that's oxidized in the air. There was a lot of metal still stuck underneath it, though, so a higher temperature and skimming that stuff off would definitely help.
Also be careful with the fumes. Aluminum Oxide is not something you want getting into your lungs! That, plus the other unknown fumes from the surface of the can - paint, plastic, etc. Also, try this with copper and see if you can get an ingot. I suggest getting strands of wire from any nearby construction project. Cheers!
I'm amazed that this worked because without any refractory your furnace has zero insulation, most of the heat is probably wasted leaving little of the energy to actually melt the aluminum. As far as safety goes, I'd suggest long handled tongs to keep the heat away from your hands, thick gloves, a full face shield, maybe a welders helmet with a good dark visor to protect your eyes from the glare, and that makes it easy to see how the melt is going on. Perhaps a leather apron (like a blacksmith might use), well you get the idea. Oh, make sure your mold is sitting on dry sand. If any molten metal falls on a wet surface the resulting steam explosion will send hot molten metal flying, that's when that leather apron will come in handy!
every time we go camping (every once or twice a year) i get all the soda cans in a pile and feed em one by one into a steel soup can and when it cools i usually find that its just a stack of crushed cans that can be pulled apart with a tiny bit of melting going on at the very bottom, I'm thinking about taking an air mattress pump and a steel pipe and feeding it some air, bellows would be way cooler and wouldn't need batteries or be loud as shit, lol I'm the type of guy who will hand make my own bellows out of whatever, car tires and stuff, that should get that camp fire aluminum ingot i wanted all along
Actually burns can be way worse if plastic melts on your skin... You'd better get your skin to touch lava directly.. Counter intuitive but clothes dont' protect from burning except clothes that are specifically made for that.
Next time I would suggest having two furnaces. One for meltdown, the other for the mould. After each melt, I'd suggest transferring the molten aluminum into the 2nd preheated mould furnace held at a higher temperature so that it will stay molten. I was aircraft metals tech in the Air Force. One thing I can say is that what happened to those cans is a reaction called eutectic melting. Basically, 90% of applicable aluminum is an alloy called copper aluminide, or AlCu. The aluminum is trapped inside a matrix of copper which is what gives it its strength. Kind of like microscopic honeycombs or a cobweb. Now what you're seeing when you quenched it is an uneven and rapid cool down. If you insulate the 2nd furnace with firebricks somehow, you'll get better results with the finished metal, especially if you can control the cooling more gradually by turning down the air supply for several minutes. It won't be perfect but it'll be better. By quenching the aluminum, the copper and aluminum rapidly trap in place. The copper has a lower melting point than the aluminum, so if you cool it gradually, the aluminum will set in and harden and allow the molten copper to re-matrix, and you'll end up with a better, more consistent product throughout. Happy moulding!
Cody Terrill Great info! One correction though: copper's melting point is higher than aluminum. Maybe they behave differently in an alloy. From my research, though, beverage cans contain very little (if any) copper in their construction.
mrhomescientist right! It's been a while since I've had my nose in the books. Sorry if I let off some inaccurate information. However it doesn't take too much copper to create that alloy. It's less than 3% in base form I believe. Usually pure aluminum is only found in lab-grade specimens when being tested for other applications. I'd say the majority of other aluminum alloys is AlCu. Since copper is expensive, I believe they may add other alloys into the AlCu, such as tin, in order to create a cheaper cost to produce. Which in turn, will lessen the percentage of copper in the alloy. Now that you mention it, those flakes could be solidified tin. I believe tin is slightly more dense than aluminum which would explain why they sank to the bottom of the melting pot. Correct me if I'm wrong. I don't have my periodic table available :p
For just slapping some things around the house ya have, it worked surprisingly well, I love things like this where its barebones but effective for some experimentation
to reduce slag, add common table salt. I found that it reduces the slag tremendously. I am about to rebuild my furnace ( old 20# LP Gas tank, past its last fillable date) with 1-inch thick fiber fire blanket (2600F) from amazon cost $7.00. cannot wait to start casting stuff ... and who care what people say about YOUR SAFETY. its YOUR SAFETY not theirs !!! you want to wear shorts, or be nakid so be its YOUR FREEDOM to do so !!! OOH RAH !!!! Your idea of the hair dryer is pretty good, I will have to add that to my rig! (thank you for the idea)
Try building a rocket stove out of some cinder blocks and put your charcoal chimney on top of it.You may get enough draft through the rocket stove and you may not need the hair dryer.Or you may be able to eliminate the charcoal chimney altogether and melt the cans right on top of the stove.
The plastic gloves you are wearing are a bad idea is is the idea of no shoes. If you splash aluminum on those gloves, they will melt and stick to your hands, causing a much more severe burn than if you had no gloves on. You should stick to all leather gloves for handling aluminum. No shoes is probably better than laced up shoes. Metal down the laces can really burn you because you cannot get the shoe off easily. You will get a better yield on you aluminum if you crush the cans first. The method you are using exposes the surface to the air as it melts and allows it to oxidize. Crushed cans will allow you to put several cans in at the same time. A top on the melt pot would help keep oxygen out. It would be a good idea to use a refractory coating on the steel pot you are melting in. That will stop the aluminum from sticking to the steel and eventually eating a hole through it. Lacking real flux, you can use table salt on top of the metal to slow down oxidation, just skim it back before pouring or use a skimmer and remove it first. The salt is lighter than the metal and will float.
man what a cool video you have here, thanks. As soon as I leave this apartment, Im going to be doing this for sure. Dont worry bout the shoes man, people get to excited over any little thing these days. Take care!
I like the cobbled together nature of your little foundry. Screw the safety Nazi's, i get them all the time. the reality is the safest thing you can do is NOTHING at all. Your feet, your choice. keep up the good work!!
+Ray Pena Thanks! I sort of regret that this has become my most popular video. It was really a last-minute thing that I shot only because the video I wanted to do didn't pan out, so I didn't think things through as well as I should have. I plan on making another aluminum-related video in the future to address the safety issues that 80% of people comment about.
I donno if anyone has said this yet but you really need to wear a filter mask when doing this aluminum fumes are very toxic I know this because I am a welder and I have worked with aluminum for years. Go to a hardware shop and ask for a mask that is raited for aluminum welding.
We had a charcoal grill with aluminum grates. I did a cookout. When I was done I closed the lid on the grill and left it. The next morning there were chunks of melted aluminum under and the in the grill. The grates were gone. I didn't intend to melt them. I don't remember how the wind acted during the night. I'm sure it played a roll in the melting of the grates.
Well done capturing this first experiment on video and achieving some melt. I love how every back yard melter invents a slightly different setup based on what's lying around😁. I've been using an air mattress inflater with limited success, I need a hair dryer!
I have been looking into metal smelting for some time now, and your video has helped me out a lot. Even giving safety tips and precautions (like shoes). Also have you considered cast iron cup in place of steel?
Bernardo Buttler Haha and I always shake my head at people who wrap fish or meat in aluminium foil and cook it on bbq, all that toxic going into the food.
One thing i can suggest is changing your setup so that your blower goes into the side of the can instead of the bottom. That way if your crucible fails you wont have bits of molten aluminium spraying into the air. Its also a lot less messy, i used to have mine set up like that and there would be flakes of wood and other stuff flying everywhere.
Hey man ya didnt burn your feet so its all good, if you ever make a video and you want to know if you did anything wrong just put it on youtube. People on youtube love to point out mistakes, yet look at them they are sittin on their computer, NOT making an aluminum furnace which I think is really badass btw
Jason Wright Yeah no kidding. Nobody reads descriptions or turns on annotations either, which I use all the time to update videos when people point out things I could have done better. Appreciate the comments!
The laugh is the best. Love the video. I have tried this before and I can tell you it works better than you think. Aluminum has 1221F melting point which you can easily accomplish with oxygen force. Anything above that I think you would need other chemicals to get to higher temps.
Neat! I tried this but in the center of a very hot bonfire. Got it hot enough to melt, but not hot enough to pour. Relatedly, I think by turning the hair dryer off and letting it cool while you talked, you lost some molten aluminum in the process. I don’t think everything left in there was slag. I think you’d have had more of an I got if you’d kept the blower blowing WHILE you pulled the cup out and poured it
Thanks for telling us about those alloys! I was always wondering what the crap I kept getting from my aluminum was. And you really don't need shoes for this, I think that you'd burn right through them if you touched any of that stuff! Water soaked rags work WAAAY better.
+Scott Wolford Yeah it was actually a fair distance underneath the coals, blowing up into them from below. I don't think the video made that very clear.
+kate jackson I don't know the exact time because this was a few years ago, but it wasn't very long. Things started melting within minutes of turning on the air supply.
+Jeffrey Dan Aluminum is super easy to tap and work. Plus alloy some copper in there and you have pretty close to aircraft grade aluminum. Be nice to be able to lost-wax cast a custom bike part... like I need a camera and/or LED light mount to my rockshox because the handlebar stuff gets in the way.
That's cool. Might want to change that pvc elbow piece to something that could withstand a bit of heat. I imagine that'd melt pretty quickly if you really got this thing going.
Have you tried blowing steam into the charcoal? Look up the design of Blast Furnace, adding steam to burning charcoal will produce carbon-monoxide which make the fire burn hotter. The trouble is that blast furnace is hot enough to melt iron, so your equipment may melt too. Industrial strength aluminum furnace uses an induction coil wrap around a ceramic crucible. The alternating magnetic field heat and melt the metal inside without heating the ceramic. Not sure if household electricity is strong enough to power an induction furnace though.
Thanks so much for the help I went and bought every thing I needed for this design and made it then I went to the local school dumpster and food a TON of cans so far I have about 8oz of aluminum Thanks again bro!!!
Shouldn't that be done in a low-oxygen enviroment to prevent it from being turned into aluminumoxide? Aluminum oxidizes really easily, but when in a solid state, it will form a protective layer on top of the pure aluminum and the oxidisation will stop. Because of aluminums low melting temperature, pure aluminum is the most enviromentally friendly material of those used widespreadly, but because stripping oxygen from aluminum takes a shitload of power (about 10 times more than remelting), remelting should be done in a big facility where the conditions are controlled. :)
Good point. CO2 is pretty easy to obtain, and it's heavier than air, so you could fill the crucible with it, though one this small might be harder.. if it were deeper, it would probably hold CO2 better.. You could even generate CO2 at home with Baking Soda + Lemon Juice/Vinegar, capture it in a balloon use that to fill your crucible to keep O2 levels down.
Sean In this setup, it gets difficult because just pouring CO2 down into the crucible would extinguish the coals! You'd need to build some sort of enclosed setup where you could deliver a constant stream of inert gas to the reactants only. I'm actually working out how to build something like that for another project.
mrhomescientist The crucible is the bit that the metal is melting in, not where the coals are. If you had a piece of pipe with a valve on it, and a balloon filled with CO2 on the end, you could insert the free end into the melting pot then open the valve. the heat currents would probably keep the air mixing a bit, but if you kept injecting it, and if the melting pot was deep enough, I bet it would settle in there. Just an idea, I've never tried it, but I will next summer when I get to melting. Or it might all be just a waste of time because once a layer of oxide forms on top you usually don't get much more than that. The trick is to get the new additions submerged asap so they don't have time to oxidize in the heat. Crushing cans and having a tall skinny melting pot to minimize surface area exposed to air would help.
Sean I know what the crucible is, but if you just pour CO2 into the open crucible it would overflow and spill onto the coals outside it, extinguishing them. Plus the high heat would make it prone to escaping faster. Despite being heavier than air, these cover gases (CO2, Ar, etc.) will still diffuse away fairly quickly. I've seen it with SF6 - even though it is 6x heavier than air it escapes containers surprisingly quickly. So, you need a constant flow of gas to replenish what escapes. As I said above, you'd need an enclosed crucible with a gas inlet and outlet, to which you'd supply a constant stream of inert gas. It sounds like you were heading towards that idea in your last post. Experiment with it if you get the chance!
Cool looking glob. A shorter extension cord with larger gauge conductors might also be helpful to compliment the hairdryer's cord length so your blower stays efficient. Maybe weigh the glob to see what the net weight is per the gross amount of cans?
The Hillbilly Home Coffee Roaster yeah its actually safer without shoes because if the molten metal hits your foot it will burn you and also roll off but if there is shoes it will get trapped and cause a major flesh wound
Very cool now how can we make moulds to make things. I love youtube and people who try to keep ingunity alive instead of using computers all the time. Barefoot might well be a bad idea but in most countries they do far worse barefoot a glass of whine anyone?
I made an aluminum furnace... I dug a hole in the ground and made a tunnel for air. Then i filled it with wood and charcoal. In the hole for the air, i put a French drain pipe in it, then hooked my Husqvarna backpack blower to it! That thing sounded like a mini jet engine and melted the can quickly! Probably would have eventually melted the steel pot(it was glowing). I would like to know what you think. I might make a vid of it.
You wouldn't believe the number of people that feel the need to comment on it, despite how many times I write about it. It's good to correct myself in case someone else tries this - I wouldn't want anyone getting hurt for repeating my mistakes.
dj anthony I wasn't thinking. I threw this idea together pretty quickly and didn't think through my safety precautions. I now always use a welding jacket, welding gloves, a face shield, jeans, and boots whenever working with molten metals, as should anyone else that attempts this.
mrhomescientist I'm a 14 year old boy that lives in the uk,is it legal for someone my age to do this?,i want to try and do this but i dont know if it is legal.
dj anthony Melting metal has no age restriction but grown ups from your neighorhood could get suspiscous and contact your parents, Atleast that happend when i made one
Glad I found your video! I am doing the same thing, just a little different setup. What got my attention was the camping cup. I wasn't sure it would be thick enough but bought it anyway just to try. I know now it will work. Thanks for sharing!!
Good luck! Mine didn't last all that long, though. It became perforated after just 3 or 4 aluminum melts. It goes with the 'cheapo' theme of the video, but there are definitely better crucibles to be found/made!
[12-05-20] In 2015 this might have been cutting edge. But, in 2020 Rocket Mass Smelters are the way to-go, with better electric Bellow Fans. You left a lot of aluminum in your Crucible. For some of us in the 2A community cast 9MM bullets as practice rounds reloading. You do need to adjust the power load to compensate for difference load weight, for accuracy.
Dan Lewis Hiding behind big words doesn't make you any different than FPSAmerica. In fact, you pretty much contradicted your "Please grow up." statement with your infantile remark "Your videos stink." The best way to deal with his redirection of your original comment would have been to remain silent.
I call 'em as I see 'em. You want love? Get a dog. If you put up bad/dangerous/stupid videos and if I want to, I sure do have the right to express my opinion about 'em, you dirty anti-freedom commie. Go back to the Taliban where you belong, fool. Time for you to man up and take criticism, dummy. You put it out for folks to see. Live with it. When you do a good video, and I see it, I will say so. Admit it, fool, you don't really care about the quality of your videos. If you did, you wouldn't have folks telling you about it. Wake up. Can't stand the heat? Get the fuck out of TH-cam. Simple as that.
Hi m8. I was thinking... To produce more heat, try to use coke instead, it will not produce any ashes at all and it will heat about 3-4 times more and longer than charcoal. And to prevent heat loss, see if you can find a conical container to your chimney, and in the top of your chimney cut some "groove's" with an anglegrinder. The idea you used wit the hairdryer is perfect.. :-) Best regards from Denmark.
Hi, Well done, terrific job! Just one thing, Is there a way you could perhaps run a gas torch along a row of tins before putting them in to melt. If my guess is correct, and I am not at a certain on that, the slag will be pretty much the plastic printed film on the outside, if you can raise a bubble on it before you melt it you may be able to tear it off easily. I don’t know because I do not drink any canned stuff so can’t try this. It would give a pretty slag-less mix though and if you are trying to judge it by volume it would make things easier.
Interesting at the point you suggest a steam explosion. I'm going to go for something else. I;d suggest that the coating inside the can began to vaporize with heat, and then flashed. That would explain the brief flame and rapid expansion of gas. Just a guess though.
+lazaglider That's probably more likely than steam, since I had dried them before melting. In the heat of the moment (pun intended) I sometimes make somewhat silly observations.
I noticed u mention the steam explosion. One thing to do is make sure u don't put cans in upside down. With the hole covered the "explosion" has nowhere to go so it WILL go into molten metal because it will give before the can and u will shoot molten aluminum out with it.. Also if feeding cans quick, wait for the steam release before pushing next can on top.
that isnt slag... its aluminum that resolidified because you didnt either heat it up far enough, or waited to long, or both... plus if you keep that in water, if you did over 100 cans... you would find out that it has the left over acid that dried out, it will bubble for a week, and smell really bad... but after a couple weeks of that, the real slag will detereriate off, and you will see that you have a lot more aluminum left... I know, I did that with my forge, out of about 60-100 cans, I got about 7 mini muffin forms out of it, and about a muffins worth of "slag" then I put that "slag" in another container, filled it with water and let it bubble and acidic off all the real slag... still have a lot of aluminum left, about 99% I should say...
He does have a lot of aluminium oxide, almost all the foil oxidised since it has a very large surface are for it's little volume, it didn't melt because aluminium oxide has a high melting point
... Nice shoes. Sorry man, I couldn't resist. Great video though. Have you done a cross section to any of the ingots you've poured? I've been wondering how many air bubbles ends up in this type of pour.
That's actually a good question. I see a lot of videos that 'degas' the aluminum before pouring, and supposedly that really needs to be done if you want to use it for structural items. Worth a look!
BTW I had heard of this ton in the back pages of popular mechanics... using an old furnace blower. You should be able to score one at a thrift store like axman surplus (rheem has speed control on some of theirs). Squirrel cage fans are also in some air conditioners which would be all over and less power than the furnace but probably more than the hair dryer.
Al melts @ 1220 F. Good job. I did this once, with my Dad's brand new grill and a shop vac/blower. Bad idea, since the grill was made of thick cast aluminum. Not only did I blast furnace a hole in the back of the grill, I set the back yard on fire to boot. However, it did guide me towards a career. I have been a firefighter now for 28 years. I fixed Dad's grill with a piece of metal road sign and some self-tapping screws. He was still awful pissed off at me though. There is just no pleasing some guys. Cheers from Texas.
Nice try ;) I've worked in aluminium casting industry, it's pretty fun^^. For safety, I strongly recommend to dry the cans before melting them. a single drop of liquid in the crucible can make it explode (it happens at my work once in a 40 tons furnace, over 6 months of maintenance stop for the furnace, the loading machine and some equiments around. 14 years after the accident, you can see some marks on the walls and the ceiling of the foundry, but fortunately no one had been injured).
Yikes! Sounds like a fun job.
mrhomescientist I am a maintenance tech, so I don't work directly in the process. heavy industries like this are heaven for techs, even with the risks. these accidents are very rare, they happen usually when somebody unaware of safety directives throw an empty can, but still wet, into the dried scraps boxes just before the loading. If you like big machines and technologies and if you have the chance to visit an aluminium industry plant, take it, you can learn a lot^^
Same thing happened at a Alcoa plant in AZ. Blew the whole building up.
Learned that one the relatively hard way. I have a tiny bucket forge and was melting a can that still had some soda in it. It was cool at first, until a tiny bit of the hot liquid landed on my forearm. Never again.
Did you wear shoes there?
I've just gotten interested into melting metals and making ingots and a lot of the videos I've seen have made it look really hard. This video on the other hand, made it look very easy and actually possible, so thanks!
Very cool crystals on the aluminum. I really like your videos. I hate all the people worried about safety... Just a bunch of unadventurous people scared of their own shadow!
I totally agree!
Hey it’s the back yard scientist
Safety is good for dirt biking and stuff like that but not all
Wait till you spill on your feet
No we just like making fun of stupid ppl. We would love for u to keep talking too.
In my experience if you sorta skim off that slag periodically you get a better ingot at the end, I used a steel spoon for that. However, that stuff is protecting the rest of the molten metal from oxidation, so leave a layer on there until it's time to pour. Fortunately it floats.
I NEVER do this because I HATE safety dinks, but brother, you gotta wear some shoes. Sometimes it pops and little (or not so little) bits of molten aluminum go flying, and if that hits bare skin you'll be very unhappy. And sometimes you dont see where the drops land, and then you step on them in the grass, and well, it hurts.
Ask me how I know this.
It's late but how do you know
How you know this?
If you use the metal tubing and the silicone hoses and hose clamps from a front mount inter-cooler setup for a turbo car as the pipping it will be a lot more secured to the hair dryer, and a lot more reliable. Other than that good idea, it seems to work really well. As for what shoes to wear, Mack Boots are awesome, and I've had the pair I'm wearing now since 2008. They still have plenty of rubber grip left, nearly like new actually, and I did security in them for 5 years. They breath very good, and I never get sweaty white spots on my feet from them, but as soon as I wear cheap sneakers for a day it's another story. I love my Mack Boots. Totally worth the $140au I paid for them.
If you pour the aluminum while it's still hot you get much more turnout. What you said was slag looks like it's mostly cooled aluminum
Thats what i thought
Technically it's dross, aluminum that's oxidized in the air. There was a lot of metal still stuck underneath it, though, so a higher temperature and skimming that stuff off would definitely help.
Reluctant Couch I done this once and I got lots of cooled down aluminium wich I thought was slag
but was pure aluminium
Amazing - never thought about it with the amount of cans we use at my house. Thanks I am going to give this a try!
This the best TH-cam video. Who would of thought something this simple
could cause a riot, must be all the positive energy.
Keep up the good work.
i find it hilarious that this man has been looking for comments about shoes and deleting them for almost a decade
Nice work. You should mention that aluminium melts at 660.3°C or 1220.54°F
How the hell did i get here?
@Brad Hissman I never chose to be born
Ask your doctor! 😂
TH-cam is one hell of a drug
Watching the days go by…
@@RobbieWhiplash that’s where my mind went with it lol.
Also be careful with the fumes. Aluminum Oxide is not something you want getting into your lungs! That, plus the other unknown fumes from the surface of the can - paint, plastic, etc.
Also, try this with copper and see if you can get an ingot. I suggest getting strands of wire from any nearby construction project.
Cheers!
copper's melting point is quite a bit higher than aluminium.
You should cover the top of the device. It will melt your aluminum faster by trapping heat.
would make it less simple
I'm amazed that this worked because without any refractory your furnace has zero insulation, most of the heat is probably wasted leaving little of the energy to actually melt the aluminum.
As far as safety goes, I'd suggest long handled tongs to keep the heat away from your hands, thick gloves, a full face shield, maybe a welders helmet with a good dark visor to protect your eyes from the glare, and that makes it easy to see how the melt is going on. Perhaps a leather apron (like a blacksmith might use), well you get the idea.
Oh, make sure your mold is sitting on dry sand. If any molten metal falls on a wet surface the resulting steam explosion will send hot molten metal flying, that's when that leather apron will come in handy!
every time we go camping (every once or twice a year) i get all the soda cans in a pile and feed em one by one into a steel soup can and when it cools i usually find that its just a stack of crushed cans that can be pulled apart with a tiny bit of melting going on at the very bottom, I'm thinking about taking an air mattress pump and a steel pipe and feeding it some air, bellows would be way cooler and wouldn't need batteries or be loud as shit, lol I'm the type of guy who will hand make my own bellows out of whatever, car tires and stuff, that should get that camp fire aluminum ingot i wanted all along
When making a fire hot enough to melt aluminum always wear shorts, sleeveless shirt and bare feet. :)
Lol ^
Yolo
Bare feet plus molten metal = hot foot.
I know u
que saben ustedes!!!!! se hace la fundicion de aluminio en verano, totalmente desnudo!! no arruinar la vestimenta jajajaja
your feet will heal, if you burn up a good pair of shoes, that's a hunnert bucks.
I do everything barefoot
May*
Well when you work with melting lead that isn't a good idea lol proper foot wear is always key even if it means throwing them away after constant use
uh no if you get burned the scars won't heal
uh no if you get burned the scars won't heal
Actually burns can be way worse if plastic melts on your skin...
You'd better get your skin to touch lava directly.. Counter intuitive but clothes dont' protect from burning except clothes that are specifically made for that.
Next time I would suggest having two furnaces. One for meltdown, the other for the mould. After each melt, I'd suggest transferring the molten aluminum into the 2nd preheated mould furnace held at a higher temperature so that it will stay molten. I was aircraft metals tech in the Air Force. One thing I can say is that what happened to those cans is a reaction called eutectic melting. Basically, 90% of applicable aluminum is an alloy called copper aluminide, or AlCu. The aluminum is trapped inside a matrix of copper which is what gives it its strength. Kind of like microscopic honeycombs or a cobweb. Now what you're seeing when you quenched it is an uneven and rapid cool down. If you insulate the 2nd furnace with firebricks somehow, you'll get better results with the finished metal, especially if you can control the cooling more gradually by turning down the air supply for several minutes. It won't be perfect but it'll be better. By quenching the aluminum, the copper and aluminum rapidly trap in place. The copper has a lower melting point than the aluminum, so if you cool it gradually, the aluminum will set in and harden and allow the molten copper to re-matrix, and you'll end up with a better, more consistent product throughout. Happy moulding!
Cody Terrill Great info! One correction though: copper's melting point is higher than aluminum. Maybe they behave differently in an alloy. From my research, though, beverage cans contain very little (if any) copper in their construction.
mrhomescientist right! It's been a while since I've had my nose in the books. Sorry if I let off some inaccurate information. However it doesn't take too much copper to create that alloy. It's less than 3% in base form I believe. Usually pure aluminum is only found in lab-grade specimens when being tested for other applications. I'd say the majority of other aluminum alloys is AlCu. Since copper is expensive, I believe they may add other alloys into the AlCu, such as tin, in order to create a cheaper cost to produce. Which in turn, will lessen the percentage of copper in the alloy. Now that you mention it, those flakes could be solidified tin. I believe tin is slightly more dense than aluminum which would explain why they sank to the bottom of the melting pot. Correct me if I'm wrong. I don't have my periodic table available :p
For just slapping some things around the house ya have, it worked surprisingly well, I love things like this where its barebones but effective for some experimentation
Wife- Honey what happened to my hair dryer.
Husband- nooooothing
that's exactly what happened with me :)
It's easier to ask forgiveness than it is to get permission.
By far more dangerous than the "clothing issues"
Ever since the beginning of the human race, we have been fascinated by fire...
Wow 5 years ago how you doin now
azz boi fr
How are you doing
Safety 3rd
Yea dats meh rul
Na I think 153rd
Thats what michael says
No, 4th
to reduce slag, add common table salt. I found that it reduces the slag tremendously.
I am about to rebuild my furnace ( old 20# LP Gas tank, past its last fillable date) with 1-inch thick fiber fire blanket (2600F) from amazon cost $7.00. cannot wait to start casting stuff ... and who care what people say about YOUR SAFETY. its YOUR SAFETY not theirs !!! you want to wear shorts, or be nakid so be its YOUR FREEDOM to do so !!! OOH RAH !!!!
Your idea of the hair dryer is pretty good, I will have to add that to my rig! (thank you for the idea)
Try building a rocket stove out of some cinder blocks and put your charcoal chimney on top of it.You may get enough draft through the rocket stove and you may not need the hair dryer.Or you may be able to eliminate the charcoal chimney altogether and melt the cans right on top of the stove.
Why not just crush the cans first. One at a time placed in to gradually soften and collapse, seems inefficient.
for the dramatic effect of course
you are so creative by using a hair dryer. AWESOME!!!!!!
The plastic gloves you are wearing are a bad idea is is the idea of no shoes. If you splash aluminum on those gloves, they will melt and stick to your hands, causing a much more severe burn than if you had no gloves on. You should stick to all leather gloves for handling aluminum. No shoes is probably better than laced up shoes. Metal down the laces can really burn you because you cannot get the shoe off easily. You will get a better yield on you aluminum if you crush the cans first. The method you are using exposes the surface to the air as it melts and allows it to oxidize. Crushed cans will allow you to put several cans in at the same time. A top on the melt pot would help keep oxygen out. It would be a good idea to use a refractory coating on the steel pot you are melting in. That will stop the aluminum from sticking to the steel and eventually eating a hole through it. Lacking real flux, you can use table salt on top of the metal to slow down oxidation, just skim it back before pouring or use a skimmer and remove it first. The salt is lighter than the metal and will float.
There was an experiment done and it turns out metal doesn't stick to your hands. That being said it's still dangerously hot and can burn you.
As kids, we had many regular campfires into which we'd toss our soda cans and watch them melt. We always thought that was super cool.
man what a cool video you have here, thanks. As soon as I leave this apartment, Im going to be doing this for sure. Dont worry bout the shoes man, people get to excited over any little thing these days. Take care!
I made something like this at home and it works. computer hard drives melt down well in this setup.
I like the cobbled together nature of your little foundry. Screw the safety Nazi's, i get them all the time. the reality is the safest thing you can do is NOTHING at all. Your feet, your choice. keep up the good work!!
+Ray Pena Thanks! I sort of regret that this has become my most popular video. It was really a last-minute thing that I shot only because the video I wanted to do didn't pan out, so I didn't think things through as well as I should have. I plan on making another aluminum-related video in the future to address the safety issues that 80% of people comment about.
I donno if anyone has said this yet but you really need to wear a filter mask when doing this aluminum fumes are very toxic I know this because I am a welder and I have worked with aluminum for years. Go to a hardware shop and ask for a mask that is raited for aluminum welding.
We had a charcoal grill with aluminum grates. I did a cookout. When I was done I closed the lid on the grill and left it. The next morning there were chunks of melted aluminum under and the in the grill. The grates were gone. I didn't intend to melt them. I don't remember how the wind acted during the night. I'm sure it played a roll in the melting of the grates.
Well done capturing this first experiment on video and achieving some melt. I love how every back yard melter invents a slightly different setup based on what's lying around😁. I've been using an air mattress inflater with limited success, I need a hair dryer!
I have been looking into metal smelting for some time now, and your video has helped me out a lot. Even giving safety tips and precautions (like shoes). Also have you considered cast iron cup in place of steel?
me in summer : Im gonna do this
me back from summer: What a minute..... i forgot to do something
4:30 - but you forgot to spray the the cookie sheet with Pam!
lol
This is the simplest melting video I have seen that worked
probably the most simplest method I've seen thanks M8
You have the crystals because you didn't remove all the slag.
don't forget to inhale this stuff.. aluminium particles is really really good for the brain
It'll mainly be carbon and ash since the aluminum doesn't expel into the air. Still not good for you.
Bernardo Buttler Haha and I always shake my head at people who wrap fish or meat in aluminium foil and cook it on bbq, all that toxic going into the food.
Shame Shame Shame. smh.
I'm talking about how breathing in the smoke isn't good for you.
I'm talking about how aluminium in everything is just bad in general
when i was doing this i messed up and had my tongs touch my elbow and left a pretty cool burn mark
Battle scar
One thing i can suggest is changing your setup so that your blower goes into the side of the can instead of the bottom. That way if your crucible fails you wont have bits of molten aluminium spraying into the air. Its also a lot less messy, i used to have mine set up like that and there would be flakes of wood and other stuff flying everywhere.
By far the best smelting video I've seen and u also said how it was made
Thank you!
Ah, molten aluminum. Perfect for pouring into ant nests.
And onto Madagascar cockroaches
Bad waste of metal if you ask me
You wasted my time! I wanted back! No design, no creativity, nothing useful.
Lol i was just about to comment "Man you should really have worn shoes" but then I noticed OP will delete shoe related comments
Thanks for actually reading!
Hey man ya didnt burn your feet so its all good, if you ever make a video and you want to know if you did anything wrong just put it on youtube. People on youtube love to point out mistakes, yet look at them they are sittin on their computer, NOT making an aluminum furnace which I think is really badass btw
Jason Wright Yeah no kidding. Nobody reads descriptions or turns on annotations either, which I use all the time to update videos when people point out things I could have done better. Appreciate the comments!
Id like to make a furnace after making a clay mold so I can make an aluminum paintball gun, didn't think it was this easy so I'm stoked to try it!
Jason Wright Something tells me shoes wouldnt help that much anyways.. It would burn right through the shoe wouldn't it??
03:13 His happy Evil Genius laugh... Lmao...
The laugh is the best. Love the video. I have tried this before and I can tell you it works better than you think. Aluminum has 1221F melting point which you can easily accomplish with oxygen force. Anything above that I think you would need other chemicals to get to higher temps.
Neat! I tried this but in the center of a very hot bonfire. Got it hot enough to melt, but not hot enough to pour.
Relatedly, I think by turning the hair dryer off and letting it cool while you talked, you lost some molten aluminum in the process. I don’t think everything left in there was slag. I think you’d have had more of an I got if you’d kept the blower blowing WHILE you pulled the cup out and poured it
goo job
imagine how much aluminum foil is in land fills.
8.1% of the Earth's crust is aluminum.
nuuuuuuuuuh not the mtn dew m8
he proved to MLG for the mountain dew m8 but my question is, where are the doritos?
ikr m8
+_Fallout_Legend _ The DORITOS don`t have much MLG.
Thanks for telling us about those alloys! I was always wondering what the crap I kept getting from my aluminum was. And you really don't need shoes for this, I think that you'd burn right through them if you touched any of that stuff! Water soaked rags work WAAAY better.
I can't believe the PVC elbow didn't burn up more! I love it. Simple.
+Scott Wolford Yeah it was actually a fair distance underneath the coals, blowing up into them from below. I don't think the video made that very clear.
3:13 the can spat on you for putting it there!!
just curious, what would be the purpose of doing this? thanks.
Some people cast scrap aluminum into useful parts. I just did it for fun! Now I have a sweet brick of metal that used to be 40 soda cans.
+mrhomescientist lol that's awesome!
+mrhomescientist how much time please tell me
+kate jackson I don't know the exact time because this was a few years ago, but it wasn't very long. Things started melting within minutes of turning on the air supply.
+Jeffrey Dan Aluminum is super easy to tap and work. Plus alloy some copper in there and you have pretty close to aircraft grade aluminum. Be nice to be able to lost-wax cast a custom bike part... like I need a camera and/or LED light mount to my rockshox because the handlebar stuff gets in the way.
its a good thing it didnt splash out of there or POP and burned your bare feet. Safty first dude.
No one cares
That's cool. Might want to change that pvc elbow piece to something that could withstand a bit of heat. I imagine that'd melt pretty quickly if you really got this thing going.
Have you tried blowing steam into the charcoal? Look up the design of Blast Furnace, adding steam to burning charcoal will produce carbon-monoxide which make the fire burn hotter. The trouble is that blast furnace is hot enough to melt iron, so your equipment may melt too. Industrial strength aluminum furnace uses an induction coil wrap around a ceramic crucible. The alternating magnetic field heat and melt the metal inside without heating the ceramic. Not sure if household electricity is strong enough to power an induction furnace though.
how much mounten dew do you drink man
Seth Powell dude why be a dick maybe he drank them on that day
Jamie McCullough
good for you
you should have had a lot more aluminum, keep the fire going longer next time
I'm not sayin' wear shoes next time, but.........wear f*ckin shoes next time!
So you are saying wear shoes next time •_•
+Cameron Damon What made you think that?
+Cameron Damon No he's not. He just said he's not saying that! ;)
ha!
+Mark EM Ban him)))
Why so many haters!if he choses to lose his eyebrows in the process of making a TH-cam video that just increases ratings anyhow! Nice video!
Thanks so much for the help I went and bought every thing I needed for this design and made it then I went to the local school dumpster and food a TON of cans so far I have about 8oz of aluminum Thanks again bro!!!
+Gavin branch Great work!
The hair dryer was free!? Good find :)
Yeah he stole it off his Missus bahahahah
@@firefox00-7 only fair, she nicked his shoes for one of her dumb arse projects!! 😁
Shouldn't that be done in a low-oxygen enviroment to prevent it from being turned into aluminumoxide? Aluminum oxidizes really easily, but when in a solid state, it will form a protective layer on top of the pure aluminum and the oxidisation will stop. Because of aluminums low melting temperature, pure aluminum is the most enviromentally friendly material of those used widespreadly, but because stripping oxygen from aluminum takes a shitload of power (about 10 times more than remelting), remelting should be done in a big facility where the conditions are controlled. :)
Sure, and I lost a lot to oxidation there. Crushing the cans first would help minimize that.
Good point. CO2 is pretty easy to obtain, and it's heavier than air, so you could fill the crucible with it, though one this small might be harder.. if it were deeper, it would probably hold CO2 better.. You could even generate CO2 at home with Baking Soda + Lemon Juice/Vinegar, capture it in a balloon use that to fill your crucible to keep O2 levels down.
Sean In this setup, it gets difficult because just pouring CO2 down into the crucible would extinguish the coals! You'd need to build some sort of enclosed setup where you could deliver a constant stream of inert gas to the reactants only. I'm actually working out how to build something like that for another project.
mrhomescientist The crucible is the bit that the metal is melting in, not where the coals are. If you had a piece of pipe with a valve on it, and a balloon filled with CO2 on the end, you could insert the free end into the melting pot then open the valve. the heat currents would probably keep the air mixing a bit, but if you kept injecting it, and if the melting pot was deep enough, I bet it would settle in there. Just an idea, I've never tried it, but I will next summer when I get to melting. Or it might all be just a waste of time because once a layer of oxide forms on top you usually don't get much more than that. The trick is to get the new additions submerged asap so they don't have time to oxidize in the heat. Crushing cans and having a tall skinny melting pot to minimize surface area exposed to air would help.
Sean I know what the crucible is, but if you just pour CO2 into the open crucible it would overflow and spill onto the coals outside it, extinguishing them. Plus the high heat would make it prone to escaping faster. Despite being heavier than air, these cover gases (CO2, Ar, etc.) will still diffuse away fairly quickly. I've seen it with SF6 - even though it is 6x heavier than air it escapes containers surprisingly quickly. So, you need a constant flow of gas to replenish what escapes. As I said above, you'd need an enclosed crucible with a gas inlet and outlet, to which you'd supply a constant stream of inert gas. It sounds like you were heading towards that idea in your last post. Experiment with it if you get the chance!
the 2015 ford trucks will be made out of aluminum maby you can melt a ford truck in 2015.
wouldnt be worth anything 2nd hand after the depreciation, so he could definatley
And the funny thing is, the melted goo will be worth more than the truck.
The planes you ride on are made of aluminum and plastic too
Luis Valenzuela The are made from tempered stell lol
Tace Sinclair Steel*
Dude make inlay pieces for woodwork, you can sand and polish them flush with the surface of the wood for some striking effects...
Cool looking glob.
A shorter extension cord with larger gauge conductors might also be helpful to compliment the hairdryer's cord length so your blower stays efficient.
Maybe weigh the glob to see what the net weight is per the gross amount of cans?
and this video is sponsored by Mountain Dew
I weld barefoot in my shorts. No problem that keeps you safer anyway. Lol.
The Hillbilly Home Coffee Roaster yeah its actually safer without shoes because if the molten metal hits your foot it will burn you and also roll off but if there is shoes it will get trapped and cause a major flesh wound
i use safety boots and get zero burns.
Leidenfrost effect
Yes I agree, I've seen very bad burns from welds that when down into your safety boots.
Seems you are well protected incase accidents happen
y u bein sarcastic. thats rude.
Im with you lot, I'm so making one of these on the weekend!!
Why is it so satisfying to watch aluminum melt
put a full can in!
it's gonna explode and very hazardous
i like burning thing too 0o
Very cool now how can we make moulds to make things. I love youtube and people who try to keep ingunity alive instead of using computers all the time.
Barefoot might well be a bad idea but in most countries they do far worse barefoot a glass of whine anyone?
That giggle was worth watching the video alone.
I made an aluminum furnace... I dug a hole in the ground and made a tunnel for air. Then i filled it with wood and charcoal. In the hole for the air, i put a French drain pipe in it, then hooked my Husqvarna backpack blower to it! That thing sounded like a mini jet engine and melted the can quickly! Probably would have eventually melted the steel pot(it was glowing). I would like to know what you think. I might make a vid of it.
I'm gonna try it naked.
Like HOW TO BASIC?
Gabriel Machadi
Exactly.
mrhomescientist Have you told your mum where was her hairdryer ?
She's the one that gave it to me!
mrhomescientist im assuming there is a grate under the charcoal to allow for air flow?
Faygot
Right. The coals sit on top of the grate.
why do you apologize yourself due to omitting some safety precautions? It's your business... ;)
You wouldn't believe the number of people that feel the need to comment on it, despite how many times I write about it. It's good to correct myself in case someone else tries this - I wouldn't want anyone getting hurt for repeating my mistakes.
mrhomescientist why arent u using shoes?
dj anthony I wasn't thinking. I threw this idea together pretty quickly and didn't think through my safety precautions. I now always use a welding jacket, welding gloves, a face shield, jeans, and boots whenever working with molten metals, as should anyone else that attempts this.
mrhomescientist I'm a 14 year old boy that lives in the uk,is it legal for someone my age to do this?,i want to try and do this but i dont know if it is legal.
dj anthony Melting metal has no age restriction but grown ups from your neighorhood could get suspiscous and contact your parents, Atleast that happend when i made one
Glad I found your video! I am doing the same thing, just a little different setup. What got my attention was the camping cup. I wasn't sure it would be thick enough but bought it anyway just to try. I know now it will work. Thanks for sharing!!
Good luck! Mine didn't last all that long, though. It became perforated after just 3 or 4 aluminum melts. It goes with the 'cheapo' theme of the video, but there are definitely better crucibles to be found/made!
Robin IsRobin I would recommend you to make something like Grant thompson did, with the sand and plaster of paris.
MrAmpuja I tried making that refractory mix but I didn't get it to work out. It just cracked and crumbled on me!
mrhomescientist Did you try to add more plaster of paris? Cement is also pretty good as a substitute.
MrAmpuja Nah I just tried the one time. Definitely worth revisiting.
[12-05-20] In 2015 this might have been cutting edge. But, in 2020 Rocket Mass Smelters are the way to-go, with better electric Bellow Fans. You left a lot of aluminum in your Crucible. For some of us in the 2A community cast 9MM bullets as practice rounds reloading. You do need to adjust the power load to compensate for difference load weight, for accuracy.
You're doing this barefooted???
You just put yourself in the Dummies Hall of Fame.
Congratulations.
Oops. I'm sorry I didn't read every little bit on the page. I still think you're stupid. ;)
Dan Lewis
Hiding behind big words doesn't make you any different than FPSAmerica. In fact, you pretty much contradicted your "Please grow up." statement with your infantile remark "Your videos stink." The best way to deal with his redirection of your original comment would have been to remain silent.
TheHibbster If you thought that was bad, you should have seen his comments before he edited them.
mrhomescientist You are the man! Having haters just means you're doing something right. Keep up the great videos!
I call 'em as I see 'em.
You want love? Get a dog.
If you put up bad/dangerous/stupid videos and if I want to, I sure do have the right to express my opinion about 'em, you dirty anti-freedom commie. Go back to the Taliban where you belong, fool.
Time for you to man up and take criticism, dummy. You put it out for folks to see.
Live with it.
When you do a good video, and I see it, I will say so.
Admit it, fool, you don't really care about the quality of your videos.
If you did, you wouldn't have folks telling you about it. Wake up.
Can't stand the heat? Get the fuck out of TH-cam. Simple as that.
brah get some shoes nah just joking good video keep it up subscribed ;)
is this legal?
Why wouldn't it be?
i was actually thinking of doing this but idk, i live in California and we're not allowed to burn anything in our back yards... ;(
That is because you live in the Socialist State of Kalyfornia.
Stassi Tokra Not even charcoal for grilling? What a sad place that must be, devoid of delicious steaks and chicken legs :(
Go to your front yard then.
I love the shoe disclaimer/warning in the description :) I like your style.
Thanks! It's a shame almost nobody reads it.
Hi m8.
I was thinking...
To produce more heat, try to use coke instead, it will not produce any ashes at all and it will heat about 3-4 times more and longer than charcoal.
And to prevent heat loss, see if you can find a conical container to your chimney, and in the top of your chimney cut some "groove's" with an anglegrinder.
The idea you used wit the hairdryer is perfect.. :-)
Best regards from Denmark.
Nice bare feet there mr safety
lol, good point.
like u will ever see my comment
+Josh's whips and lanyards I SEE EVERYTHING
+mrhomescientist #illuminati
كيمظآيمظسد
+SuperJSeven we have the same profile picture
+Ishak Ali not quite
Hi,
Well done, terrific job! Just one thing, Is there a way you could perhaps run a gas torch along a row of tins before putting them in to melt. If my guess is correct, and I am not at a certain on that, the slag will be pretty much the
plastic printed film on the outside, if you can raise a bubble on it before you melt it you may be able to tear it off easily.
I don’t know because I do not drink any canned stuff so can’t try this. It would give a pretty slag-less mix though and if you are trying to judge it by volume it would make things easier.
I've ordered a hair dryer. I've been trying this for months. I understand your happiness
Interesting at the point you suggest a steam explosion. I'm going to go for something else. I;d suggest that the coating inside the can began to vaporize with heat, and then flashed. That would explain the brief flame and rapid expansion of gas.
Just a guess though.
+lazaglider That's probably more likely than steam, since I had dried them before melting. In the heat of the moment (pun intended) I sometimes make somewhat silly observations.
I noticed u mention the steam explosion. One thing to do is make sure u don't put cans in upside down. With the hole covered the "explosion" has nowhere to go so it WILL go into molten metal because it will give before the can and u will shoot molten aluminum out with it..
Also if feeding cans quick, wait for the steam release before pushing next can on top.
that isnt slag... its aluminum that resolidified because you didnt either heat it up far enough, or waited to long, or both... plus if you keep that in water, if you did over 100 cans... you would find out that it has the left over acid that dried out, it will bubble for a week, and smell really bad... but after a couple weeks of that, the real slag will detereriate off, and you will see that you have a lot more aluminum left... I know, I did that with my forge, out of about 60-100 cans, I got about 7 mini muffin forms out of it, and about a muffins worth of "slag" then I put that "slag" in another container, filled it with water and let it bubble and acidic off all the real slag... still have a lot of aluminum left, about 99% I should say...
I do
Actually I'm sure anyone who wants to get into aluminum casting would. also a good use for those extra cans.
He does have a lot of aluminium oxide, almost all the foil oxidised since it has a very large surface are for it's little volume, it didn't melt because aluminium oxide has a high melting point
... Nice shoes. Sorry man, I couldn't resist. Great video though. Have you done a cross section to any of the ingots you've poured? I've been wondering how many air bubbles ends up in this type of pour.
That's actually a good question. I see a lot of videos that 'degas' the aluminum before pouring, and supposedly that really needs to be done if you want to use it for structural items. Worth a look!
Great test of the low cost, simple concept. I’d like to do some smelting and casting for machining.
BTW I had heard of this ton in the back pages of popular mechanics... using an old furnace blower. You should be able to score one at a thrift store like axman surplus (rheem has speed control on some of theirs). Squirrel cage fans are also in some air conditioners which would be all over and less power than the furnace but probably more than the hair dryer.