# aluminium melting



## tonyd (Sep 18, 2008)

dont know if anybody can help with this but the question is.
I now have approximately 300 pounds of heatsinks harddrive cases etc and they take up a lot of room. if i was to melt it down into ingots would it be worth more money or not, it would help for storage space, i can vaugely remmember my school days in the metal work classes where we used to do aluminium casting so i think i could do this. any help on this would be appreciated.
Tony D UK


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## Smitty (Sep 18, 2008)

Tony, may I ask what procudure is used to melt aluminum? Just sell it by the hundred pound to the recycler and don't waste your time melting. Your still going to get the same price without the extra effort.


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## tonyd (Sep 18, 2008)

thanks smitty
I dont want to sell it yet i just want to save some space. I want to wait until i have a ton before i sell so you can imagine the space this takes up.
I use a ten ton press to compact my copper wire and it saves one hell of a lot of space.
Again i dont want to sell until i have a ton of copper, i press the copper into house brick size blocks and they stack easy plus my mates wet themselves when they see these bricks.
Thanks for your input


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## Anonymous (Sep 18, 2008)

it would most likely be worth less because it would be classed as cast aluminum, or if they have doubts on metal content die cast or something like that way less price.


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## tonyd (Sep 18, 2008)

Thanks james never thought of that, Oh well i thought i might save some space but it looks like it will have to stay as it is, thanks for your thoughts.
Tony d uk


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## Platdigger (Sep 18, 2008)

James is right. Your heat sinks generally go for extrusion, and bring the most money here. (Before you melt them.)

The hard drive cases are most likely cast, and bring a bit less in these parts.
Randy


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## tonyd (Sep 19, 2008)

thanks for all the input
this is why i like this site, you just know somebody will give you the right reply.
cheers


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## Rag and Bone (Sep 19, 2008)

My heatsinks go as "mixed 6000" grade. I would be thrilled if I could get the extruded price for it.


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## Anonymous (Sep 19, 2008)

if you really want to melt your ali you could build your own furnace, fired with used motor or veg oil

have a look at this site, the guy is based in the uk and gives you a list of material suppliers.

http://www.artfulbodgermetalcasting.com/

i'm in the process of building mine, to melt both ali and copper, like you, to reduce my storage space requirements, the scrap merchant i use pays the same for extruded as cast.

i must add that i make no gain by you getting a copy of his plans.


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## tonyd (Sep 20, 2008)

Hi marty
Just had a look at the site you put in your message.
I think i will think about this then speak to my local scrap yard as i know them v  ery well, if i can cast and not affect the price that is what i will do,
I am scrapping between 30-40 computers a week so space is important.
I have not refined anything yet so that is why i want to save space.
I intend to refine stuff next year.


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## qst42know (Sep 20, 2008)

Unless you are casting something useful for yourself I suspect you will waste a whole bunch of money on fuel as aluminum soaks up a lot of BTUs before it melts. Besides open aluminum casting is hot dangerous work. The proper safety gear will be expensive full body hi temp reflective clothing, gloves, boots, face shield, etc. Even where you cast is critical, molten metal spilled on concrete is explosive. Several inches of dry sand floor would be required. A couple pounds of molten aluminum is not even in the same league as ounce or two of PMs. Crushing or cutting would be safer and far less costly space or no space.


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## Lou (Sep 21, 2008)

Melting even 19 pounds of aluminum is cake--about 20 minutes from cold start then about every 7 minutes after that. If all you're after is pigs from popcans then you're in for a stinky, hot process. Fun for all of the first half hour, then tedium. I really don't think melting aluminum is that difficult, or even cast iron. I think magnesium is a pain, and so are some types of brass. Actually, I'd say cast iron, silicon bronze, and 356 aluminum have to be the best things to melt and cast! As far as making money on it, I know that many places will pay more for ingot than for other forms.


I know two guys (one in Cincinnati) that get more for their aluminum as ingots, and additional money for the slag! The other is local--he goes to machine shops and takes all the chips and cut offs; sometimes it's a mixed bag, but at some companies they only do work or large jobs in one type of alloy and he cleans up on it.

As far as crushing and cutting goes--depending on the size of your furnace, that may or may not be needed. I know it's definitely not less costly!! I've seen furnaces built for 30 bucks that'll melt aluminum all day long. I'd rather melt up some big scrap than burn through saw blades. If I had a crusher, maybe it'd all be a different story.


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## tonyd (Sep 21, 2008)

Definately no pop cans, i am talking about heat sinks and harddrive cases only to be melted and cast into ingots for space saving purposes only.
A bit confused now as some say yes and some say no.
I can build a furnace for virtually free and run it on waste oil so cost is very low.
I think i will just see what other responses i get from this thread before i decide.
Still a brilliant site and thanks for everyones input it is very valuable. :?


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## qst42know (Sep 21, 2008)

I was not suggesting it could not be done nor that it wouldn't be fun for a while. I just don't believe it would add enough value to the end product And yes I have seen plenty of fellas pouring aluminum in jeans and tennis shoes on the web. Mighty cavalier of them. Ask any welder how much damage a radish seed sized ball of metal can do down your shirt or in your shoe. I know of a couple of guys that stepped out from behind the shielding at a die casting foundry at the wrong time, several years of skin grafts to put them mostly back together.

Estimated set up.
Home made black pipe burner $30
Refractory $150 or more
Small Crucible and tongs $100 ?
Ton of sand delivered for floor $50-$75
Tar sand and frame $100 ?
Basic safety gear face shield, gloves, boots, welders leathers. $500 and up.

Aluminum spot price bid/ask $1.12-$1.13
This is in well insulated commercial foundry's. "Gas furnaces use ~2,100 Btu/lb to melt aluminum and lose ~2-4% of the metal to oxidation."
BTU per pound 21,548 propane @$1.50/lb.

The scrap yard I deal with pays $.45/lb. for chips, $.65/lb. cans, and $.80/lb. mixed solid, and a bit more if you sort it by cast, sheet and extruded.

It would have some hobby value and would save some space, if of course you had the space to do this work. However I don't see very much profit potential here.


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## Lou (Sep 21, 2008)

There's a difference between doing it _right _and just doing it.

As far as costs go, that's up any where you want it to be. I got half a ton of petro bond II molding sand for free. I also got my refractory for a really good price. If you're dead set on doing something on the cheap, you'll make your own refractory, fire the furnace off waste oil of some sort, make your own tongs, crucibles, flasks, fluxes, core boxes and the like. Does that mean it's optimal? No!

I made my own snap flasks and much of my bench molding equipment but I've still spent thousands on my foundry setup because I like doing it as a hobby. 

I don't pretend to know how much these two guys are making or to which place they sell it; all I know is that it's profitable enough that they do it when they get the chance. 

As far as safety goes--even the safest setup can have problems, all it takes is failure on one weld in the tongs, one crack in the crucible, or one drop of sweat or water into the metal. Having had bits of nearly every common metal (and quite a few precious metals) splash on me, I've got clear preferences: aluminum, zinc/pot metals, and magnesium are the worst. Iron, silver, gold, platinum...all skitter off your skin. Surface tension thing.

As far as melting alloys...my rule is that if it's not meant for melting, then melting it will probably ruin it.


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## Platdigger (Sep 21, 2008)

I think were this really could become "worth it" is when one sets up a foundry capable of melting irony aluminum. 
With the idea of separating the metals by melting the aluminum but not the other metals. Using gravity for separation.
Thus pouring clean ingots. 
I used to sell dirty aluminum to a buyer that actually called it "foundry"
Randy


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## Harold_V (Sep 22, 2008)

That's simple to do. A furnace is constructed that allows continuous feed, directly into the furnace-----no crucible. At the bottom there is a tap where the molten aluminum runs out to a container. Steel and iron are left behind, and because the molten aluminum runs away, little or no iron is absorbed. You can feed anything that will fit in the furnace and recover the aluminum easily, stopping occasionally to remove the unwanted remnants of ferrous objects that come with scrap aluminum.
Think of feeding an aluminum head from an engine, for example. 

A friend ran just such a furnace where I used to live. He was in the foundry business, both ferrous and non-ferrous. 

Harold


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## tonyd (Sep 23, 2008)

wow what a can of worms i seem to have started, but this is what this forum is about, the input and things i'm learning are amazing.
Just to clarify the original question, I wanted to melt and cast just to save space.
When doing this in metal work classes at school years ago it was a simple process of make a mould using foundry sand melt old bits of ali and cast, a common thing to cast was a g clamp, it was great fun and not difficult.
but keep on with the input its great, and who knows i might just melt some and see.
Thanks again for every ones replies.


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## Harold_V (Sep 24, 2008)

tonyd said:


> wow what a can of worms i seem to have started, but this is what this forum is about, the input and things i'm learning are amazing.


That's right! That is what a forum is about. Fact is, we all grow from the knowledge of others. What we must be careful of is to not get caught up with morons that aren't realistic, and can't sort fact from fiction, or folks that believe in the tooth fairy. We'll almost always have people that see things from different perspectives, but with a little logic you can usually conclude what is good, and what isn't. 

I'd agree that converting scrap aluminum to ingots isn't the smartest thing to do if you're trying to make a buck, but if you have unusual circumstances and can justify the time and expenditure, why not? It's a great way to become familiar with the handling of molten metals, and could prove a good investment, depending on the commodities market. Any of us would have done well to have stored scrap of all kinds prior to the recent monumental gains in scrap prices. They're paying more for scrap copper now than it used to cost at the refinery. 

A terrible comment on the strength of the dollar, I might add. 

I wouldn't mess with sand molds. Aluminum can be safely poured to various kinds of metal forms. You can make a simple ingot mold by welding end plates on a piece of angle iron that is sawed at an angle on the ends, so the top, which would be formed by the two legs, held @ a 45° angle, would be wider than the base, or the corner of the angle. That way you have draft that allows the aluminum to release from the mold easily. The end plates would extend beyond the corner of the angle, forming legs on which the mold would sit. You likely understand that the welds would not be inside the cavity, trapping the aluminum after it's poured. 

The ultimate would be to acquire an ingot mold, but hardly necessary.

Harold


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## tonyd (Sep 24, 2008)

Well Harold thanks for that information on the mould it is really helpful.
The problem is i get between 25-40 computers a week which you can imagine starts to mount up so it was purely for space saving.
I am not in a hurry to do this just yet as i am reading everybodys thoughts before i decide.
the remark regarding the dollar was not meant to insult anyone it was simply the best rate of exchange i have ever had and it allowed me to enjoy florida even more so please accept my apologies if it upset any one.
Once again your input is valuable to me and anybody else that reads this forum.


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## Harold_V (Sep 25, 2008)

tonyd said:


> the remark regarding the dollar was not meant to insult anyone it was simply the best rate of exchange i have ever had and it allowed me to enjoy florida even more so please accept my apologies if it upset any one.



No apology necessary. You've said nothing offensive, and have displayed exemplary manners. 

The comment was mine, reflecting on how the dollar has lost its value. A good example is an ounce of gold. As far as I know, it still weighs 480 grains, yet it now takes almost $900 American dollars to purchase one. I can still remember when it cost only $35. Gasoline was also 22¢/gallon! 

*Very heavy sigh!*  

Harold


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## tonyd (Sep 25, 2008)

I know what you mean about the weak dollar, 18 months ago i paid a dollar 20 for gas, this year it was two dollars 30, and also food prices were a lot more I THINK WE ARE ALL IN FOR A HARD FEW YEARS.

Any way i started building a mould like you suggested today as i am going to start melting some ali down to see how it goes

will let you know in a few weeks time.

Thanks for the help Harold your advise on refining is priceless.


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## Harold_V (Sep 26, 2008)

You're very welcome, tonyd. Hope some of it is useful. 

I'll be interested in hearing how the aluminum project goes. 

By the way, if your objective is only to melt (not setting up a foundry for making castings), you might consider making a furnace in keeping with the one I described. It's very simple, and requires no tools for melting. Crucibles and other tools can prove costly. I seem to recall that the one I described was used with a mold to catch the discharge, so there was no further handling. You'd need two molds, so you could exchange one for the other as the first one was filled. Just a thought. 

Harold


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## tonyd (Sep 27, 2008)

Harold if you have any ideas on building a furnace to melt the aluminium, I would appreciate your thoughts and ideas, what size mould would you suggest. I have my own fabrication company constructing trucks for horse transportation ( horseboxes) so i have plenty of equipment and tons of aluminium sheet scraps as well.


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## Harold_V (Sep 28, 2008)

tonyd said:


> Harold if you have any ideas on building a furnace to melt the aluminium, I would appreciate your thoughts and ideas, what size mould would you suggest.


I'd suggest you size it in keeping with the volume you expect to process at any one time. Too large can be a negative in that it isn't easy to use a small portion of a large ingot, while small ones can be added with little effort. At some point, the ingots you sell will be re-melted---so you want to insure that they aren't too large. Don't have a clue what size that may be, however. If I had to venture a guess, I'd say keep the ingots smaller than 5" wide and 12" long. 

If you have a salvage yard in mind where you intend to sell your aluminum when you have enough, it might pay you to inquire of them if there is a penalty for melting. You may be surprised to find it is worth more before melting than after, although I don't know that. Just trying to insure you don't go to a lot of work and lose on the proposition. 

Depending on the volume you melt, the ingots you create may not be attractive. Considering they'll pour on a low volume, but continual basis, I expect you'll have some cold shuts, but that shouldn't affect their value. Starting with the mold well preheated would help in that regard. 

As far as the furnace goes, I think my advice would be to size it in keeping with the size of items you intend to melt. The smaller, the less expensive it would be to build and operate, and it would yield a correspondingly smaller amount of aluminum. My thoughts would run towards an interior diameter of roughly 12", or slightly larger. It need not be very deep----and should be formed such that there is a low side, inside, where the discharge is located. Sadly, I do not recall the size of the one I mentioned, but it was not very big. Less than 4' tall, and less than 3' diameter on the OD. He ran his without a lid. 

There are a number of burner designs on the market that run without a blower (propane), but if you intend to use waste oil, you may have to design one on your own. The oil can be sprayed though a nozzle, but unless it's well filtered, and the pressure is quite high, it may not perform well. Unfiltered oil will clog the nozzle easily, and often. 

If you have compressed air at your disposal, you may be able to use air pressure to atomize the oil-----I understand there is such a design on the commercial market. I am not familiar with its operation. 

I would suggest the port for the burner be located slightly above the bottom, tangent to the inside diameter. It would be desirable for the flame to swirl around the lining. Once heated, the lining will melt newly introduced aluminum quite quickly. 

You can expect a reasonable amount of dross, which has value as well, although you may not find a ready market. It contains a substantial amount of oxidized aluminum. If it is returned to major aluminum refiners, it is once again reduced to aluminum via arc furnaces. 

The furnace could be made of a castable refractory, or rammed, using a rammable refractory. Casting might be easier. Both methods would require an inside form, plus one for the burner port. The furnace may not require a lid, although it would be more efficient with one. One that swings away easily (on a pin that is fastened to the exterior housing) might be the solution. The furnace could be poured (or rammed) in a large steel barrel. Here in the States one might choose a 55 gallon drum, or one slightly smaller. They are easily cut to length with a torch, or even cut with an abrasive saw. 

I, too, have an interest in an oil fired furnace, although mine would be intended for melting bronze and brass, using a crucible. The design would be similar, regardless of the application. I'd appreciate hearing from you with anything you may discover in that regard. I'll keep you in mind if I uncover anything of interest. 

Sorry I'm not more help. 

Harold


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## Oz (Sep 28, 2008)

I like the use of waste oil, and yes filtering is very important if you are using a regular burner nozzle. When Harold was talking about using air to atomize the oil I believe he was referring to something based on a “Babington burner” design. The principle is to blow air through a very small hole or slit in a ball or sphere allowing warmed oil to flow over the surface. The air in the ball breaks through the film of oil on the exterior giving a fine atomized pattern. Just like the blowhole on a whale coming up exhaling. This burner is usually placed in a tube to form a burner assembly with a plate partially blocking the output, that once hot helps stop flameout with any unburned oil collected and sumped to recirculate. The rear of the tube has adjustable air control for controlling the fuel/air mixture. The advantage of this is that the oil does not need to pass through a small orifice, only air. If you have a gear pump for your oil supply you could even forgo filtering and just clean out the unburned residue occasionally. 

I have not built one of these but have done considerable research into them. My interest was because I have an engine that I run on waste vegetable oil that I get free so it would be a free heat source for the house. The engine is actually for a genset I am building. The oil does need filtering for the engine as it is a cold start diesel with injectors.


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## Harold_V (Sep 28, 2008)

Oz said:


> “Babington burner” design. The principle is to blow air through a very small hole or slit in a ball or sphere allowing warmed oil to flow over the surface. The air in the ball breaks through the film of oil on the exterior giving a fine atomized pattern.


Oz,

Very interesting. Can you enlighten me-----if that system is used, assuming one uses a gear pump-----how is the oil metered? The pressure output of the pump that is used in my oil fired boiler (heating oil #2) is set @ 100 psi. I would imagine you'd have to use some kind of orifice to control output, otherwise you'd have a run-away flame. I'm having a hard time seeing a way to use the oil without filtration, regardless of the nature of the application. I am, of course, referring to used oil. I can get a fair amount of drain engine and transmission oil. I'd appreciate your views on the subject. 

Very nice post, Oz. 

Harold


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## qst42know (Sep 28, 2008)

A gear pump wouldn't last very long on unfiltered oil as they rely on close tolerances to maintain flow.


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## tonyd (Sep 28, 2008)

once again Harold your input regarding melting aluminium is very helpful.
Just had an idea, my central heating boiler is being replaced very soon i think i could adapt this to use as a furnace as it would have pump and air control for fuel already set up and can be used with red diesel or kerosene. your thoughts on this.
I will also check with my local scrap yard for ingot versus just scrap prices this week.
Also do you think i could adapt the boiler for incineration of mother boards etc therefore gaining two operations with one unit.
sorry about all the questions did not think this thread would go this far.


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## Anonymous (Sep 28, 2008)

my thoughts exactly with the furnace i'm building, incineration of boards. the unit i'm building is claimed to be hot enough to melt cast iron, was wondering if this would be hot enough to a; melt together any metals in the boards and b; be hot enough to burn any nasties out of the exhaust fumes?
my plans fall into line with Harolds suggestions, direct melting, no crucible, a drain off for the molten metal and burner running on waste (filtered) oil with forced air. the exception to what Harold suggested is that i plan to pour into a loaf tin, the type you would use when making bread, i've used this method before to make ali bricks, the only problem is over time the tins buckles with the heat, but ingots don't need to look good do they?
marty


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## qst42know (Sep 28, 2008)

True incineration is a more controlled affair. From what I know of it (and granted that's not a whole lot). It's generally a two chambered furnace. The first volatilizes the combustibles at high temps. The second also at high temp with the addition of air oxidizes the volatiles to more basic forms. A bag house would then collect the more elemental forms that would survive both furnaces oxides of lead, zinc, and a whole bunch of others. Many compounds are broken down but many still remain.


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## Lou (Sep 28, 2008)

Regarding incineration of the computer boards---be very careful where you do it and with who you let know about it. It is quite the offense if you do it any quantity. As I recall, most of those boards are some type of bakelite with other phenolic polymers in there. Some contain chlorinated compounds.

Generally speaking, the toughest things (organic wise) to incinerate are halogenated compounds. They require really high temperatures and extreme oxidizing conditions. They also produce the acid gas of whatever halogen is in there. This usually requires about 1700*C and a minute or so residence time.


As far as oil burners, I believe I already posted a link to Cameron's oil burner. Extremely efficient, dirt cheap, and so simple to use--it will melt iron.
I don't melt with oil that often anymore, but I had a modified Brinkley-Burner which basically looks like >-< two truncated cones put together. It would melt cast iron with ease. It was propane preheated, then I'd turn on the oil (gravity fed). The oil would go through a cast in (the burner was made of a 18" piece of 4" duct work that I rammed with 3200F refractory) preheater installed in the back end of the burner to decrease viscosity. I used a leaf blower and butterfly valve at the back end. 

When it was really going it would put out a 5' cone of blue-white flame. I used it for burning up tree stumps. Wide open, it drank about 4 gallons of vegetable oil (90:10 diesel) per hour. It was a good burner, but it was a pain to make. It rolled off my bench one day and broke :-/


You ought to check out some of the reverbatory furnaces built by hobbyists out on the web. 

I've seen people buy up old crucibles on ebay (#60s), build a beehive furnace out of clay and perlite and drill a hole in the crucible and lute on a clay pipe an inch or so in diameter and a few inches long. They'd plug one end of the pipe and wait till everything was molten in the crucible and all the dross skimmed off, then they'd bust the plug on the tap and have a preheated ladle ready. Pretty simple, but quite effective.


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## Harold_V (Sep 28, 2008)

marty said:


> i plan to pour into a loaf tin, the type you would use when making bread


You can expect a different outcome if you pour copper based alloy to a bread tin as compared to pouring aluminum. One of the hazards is that the alloy will fuse to the tin. Even a mold that has been well seasoned can yield that problem----where the molten metal makes contact where it is poured, if no other place. I've had it happen with cast iron, even ductile iron molds. I think I'd advise against the idea and move towards a mold with much greater thickness.

Harold


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## Anonymous (Sep 28, 2008)

i agree with Harolds comments on pouring copper based alloys into a tin, i was referring to pouring ali into the tin mould, the copper based alloy from incinerating boards i hadn't properly thought through, suggestions gratefully received on that one.


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## qst42know (Sep 28, 2008)

I think what Lou eluded to when he mentioned chlorinated compounds is Dioxins. Dioxins, if memory serves are created by combustion in the presence of chlorine. Dioxins are a persistent environmental toxin and are the primary toxin in many of the US super fund sites. No one, not even the big corporations responsible, want the bill for such lingering problems.


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## Oz (Sep 30, 2008)

Harold,

Sorry it took me a bit to get back to you, I’ve been very busy. 

I have read the later comments in this thread and I would tend to agree that a Babington may not be ideal for melting metals but I get the impression that you were interested in the set-up of these. Again I have not built one, but talked to several people in detail that have. The gear pumps they were using were from regular home oil furnaces, they had no troubles with not filtering used motor oil or transmission fluid, most did run used vegetable oil from deep fryers through an old t-shirt though. 

As you mentioned oil fired boilers are high pressure, but they are low volume. They used them as a sump pump as they are more resistant to wear than most other pumps to the fine metallic debris found in waste oil.

To understand it better I’ll describe the path of the oil and the lighting of these. Fuel is fed by gravity from a main fuel tank to a secondary fuel tank of about a half gallon to gallon in size that in turn feds the burner by gravity. The secondary tank is kept full from the main with a valve and float similar to what you have in your toilet. A simple brass gas cock would be used for flow control from the secondary tank to the burner. Flow does not need to be very finely tuned as you just need it great enough to form a film over your ball with the surface tension. If you wanted finer control you could spin-up an oversize needle valve on the lathe. 

There is a pilot light that is propane. First you turn on your air pressure to the ball (this is relatively low pressure/volume), then light your propane pilot. Then open your oil feed to the outside of the ball. Once lit the back-plate I described earlier heats up to a red heat, then the pilot can be turned off. If turned off too early the cold thick oil tends to blow out. Here is where the usefulness of a 1 gallon secondary tank comes in. Since you only atomize the oil in front of the orifice in the ball that your air comes through, you have excess oil that runs into a sump tank. In the sump area a float switch is located to trip your gear pump to sump the excess oil back up to your secondary tank to recycle. After a while the oil gets warmed by circulating through the burner heat zone changing its viscosity and will sheet over your ball thinner giving better atomization and combustion. 

Some have used glow-plugs or resistance wire for igniters if they preheat the oil in a crock pot first as their secondary tank. This is more important with thicker oils. The main advantage of these is that you can burn almost any oil with little variance of the controls. I was going to use this as a batch heater for hot water home heating, backing up a solar parabolic water heater on the cloudy spells. If you were to want to set it up as a hands off automatic furnace or water heater you would need to always use an oil of the same viscosity. I like the fact that I can burn virtually any used or new fuel oil or vegetable oil without the tedious fine filtering required to not clog a typical burner nozzle. It is easier to have clean air.

This is getting off topic from refining in the configuration I am talking about and it may be best if it is taken to PMs unless someone else here is interested.


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## Harold_V (Sep 30, 2008)

Thanks, Oz, for the information. 

Regards taking it to PM's, I'm of the opinion that it may be of value to others, for application in a waste oil fired furnace. If we find that is not the case, and some are unhappy with the conversation, certainly, we'll take it off the forum..

Harold


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