ldebernardi said:
they sell as a kit costs $200.00 plus the cost of the refractory and propane tank and regulator.
A kit isn't a requirement, assuming you're a little handy with tools. You can start with a portion of a 55 gallon drum, or other steel container that is in keeping with the size of furnace you hope to build.
Any ideas on how much the refractory will cost?
It's been years since I made a purchase, but there's a few things you need to know. The greater the temperature you expect, the greater the cost of the refractory. If you restrict your melting to non-ferrous, you may be able to get by with a refractory that's rated for something in the 2,400° range. Please note, this is all coming from my head, I have not referenced any guidelines, so I may have a few numbers screwed up. You can expect to pay at least $50 for a 50 pound bag, and it may be more. You should be able to pour a furnace and lid with about 100 pounds. (May take more----lots more---depending on the size of your furnace and crucible).
A noteworthy comment. Refractory materials are not concrete, at least as you understand concrete. Do not assume you can substitute with Portland cement.
Refractory materials are typically available in two configurations, one a dry type that you mix with a prescribed amount of water, then the resulting slurry is poured to a container with a series of forms to create the desired cavity and hole for the burner. The other type is premixed and is called a ramable refractory. It is quite stiff, and is rammed in place, as its name implies. Both are good--and each may offer an advantage over the other, depending on your capabilities. If it matters, I've generally used the dry mix material. what is commonly known as a castable. Be advised, it has a shelf life-----buy it only when you are ready to put it to use.
Also, What is a bilge type crucible and can it be used with the kit available through http://backyardmetalcasting.com ???
Bilge type is a tiny amount smaller at the opening than it is in its midsection. Sort of barrel shaped, for lack of a better description. They are the most common type of crucible. Their design makes them quite strong when at heat, and are easy to hold and remove from the furnace, assuming you have the proper lifting tool and pouring shank. Small crucibles often use the same tool for each operation, but large crucibles pretty much require both types of tools. Breaking point would be somewhere around a #8 or # 10 crucible. The number of the crucible designates how much aluminum, in pounds, the crucible can melt. For copper, you multiply the size by three, so a number 10, for example, would hold ten pounds of aluminum, or 30 pounds of brass (or copper).
If not what type crucible should I use and how much will it cost, also what is the average lifespan of a crucible?
The cost varies according to size, and longevity is a function of how it's used. If you flux, they don't last long, maybe six to eight heats. If you don't, you may enjoy many heats, perhaps 50. For aluminum, I have no doubt, you may achieve a hundred or more.
Another question that I have is how much propane will be used per lb. of copper melted?
I can't address that question, and it's likely no one can. The efficiency of your furnace would play a role, along with many other factors.
I really need as much information as possible to see if this is worth my while. My plan is to cast ingots of copper for storage as an investment. Eventually I will sell them, and I get my copper for free or very cheap so if casting ingots is reasonably priced then I will buy the equipment to do it as a hobby.
From my perspective, it's an ill gotten idea. I tried to make mention of some of the pitfalls in my previous comments. One of the most important things to remember is that unless you can identify the material you have, you may not get much of a price when it's sold. If you store waste materials in their configurations, that's much like having American silver coins. Everyone in the metal chain knows what the items are, and can reliably predict the content. That's not true of melted materials. For example, if you melt scrap copper pipe, you're going to include some lead and tin. Even if you don't, and have cleaned up the material, you can't prove that to your buyer, so you may not get top price. By carefully sorting and cleaning your scrap, then storing it in large containers, that may not be the case. You will also have avoided the expense and trouble of melting, all for no real purpose, and certainly not for gain. Were I in your position, I'd do just what I said---I'd procure some 55 gallon drums then clean up the material, even cut it in small lengths so it can be handled easily and it takes less space to store, and I'd put it away just as it is. Alternately, I'd get involved in making castings. That way you get the pleasure of melting and pouring, and selling the material for prices well above market value of the scrap. That, of course, means you'll be forced to learn a trade--that of a foundry person.
One more question is where should I go to buy the other supplies that I will need as well as what other supplies will I need to do this? For example safety equipment such as gloves, glasses, stirring rod, crucible tongs and ingot molds?
Supplies can be purchased from foundry supply stores. Check your yellow pages, or go online and do a search for foundry supplies.
I especially need to know what tongs will work with what crucibles with the backyard metal casting kit and what medium should I use for my ingot molds.
There's several approaches to making molds, anywhere from casting to machining to welding. A nice ingot mold can be made from a length of heavy web angle iron, cut at an angle, then sides welded on each end. That yields pyramid shaped ingots, and you can tailor them to the size you desire. You can also buy molds from foundry supplies. Still, I don't recommend your plan. You'll have invested a large amount of money and effort, only to receive scrap value for the material. You can do that without the melting, as I've said. Tongs are readily available, and should conform to the vessel you choose. If you choose to make your own, make damned sure you know how to weld, and that you make them such that a hot crucible is supported in the proper place and way, and that you can't crush the crucible. If you don't know, hot crucibles become quite elastic, so they're somewhat easy to crush. Properly shaped tongs limit the ability to crush them. Bad welds have a way of letting go when the crucible is in use, filled with molten copper. Not a fun thing to experience.
I have found graphite ingot molds, but do they have the same short lifespan problem as graphite crucibles...or what is their lifespan.
Lose the idea of graphite molds. I don't like them for gold, and I damned well wouldn't like them for copper ingots. They're too easy to damage, and they change every time you pour an ingot.
Also, what is the ideal weight of copper to cast and what size ingot molds to use with the backyard metal casting kit furnace. For example what is the ideal amount to work with in one batch?
That is dependent on the decisions you make. You'd be limited by the amount of metal you can safely handle when molten. Working alone? I'd opt for nothing larger than a #20 crucible, and a #16 is likely much smarter. I'd even encourage you to consider something like a #12, You really don't want to find yourself in a situation where you have fifty pound of molten copper and it's out of control. That's more than enough to kill you and burn down your shop or house. Remember, you'd be dealing with molten metal at over 2,000° F.
How much you can melt would also be determined by the size of your furnace. Make a decision on how much you'd like to melt at one time, then build the furnace accordingly.
You'd benefit a great deal by doing some research before you make any decisions. It's much like trying to learn to refine gold. There's a lot of things that make a difference, and you'll learn about them only by studying. Spend some time on the foundry forum, and do some research to see if you can sell the ingots before you make any. Makes no sense to spend a great deal of time and money on them, to discover you'd have done just as well leaving the material as found.
Harold
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