Fe-Wood Posted April 9, 2011 Share Posted April 9, 2011 I have boxes full of drops from cutting disks for spinning. I recently picked up a foundry kit and would like to use the Copper for casting. I have cast hundreds of pounds of Everdour. Will Copper cast close to the same way? What should be careful of- Normal safety precautions excluded. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 11, 2011 Share Posted April 11, 2011 The big thing for copper is it will suck up the O2 like crazy forming a shiny copper coloured ceramic if you let it. Keep it fluxed or under a layer of crushed *real* charcoal, don't let it sit at "temp" and stirring with a DRY charcoal stick can help de-gas it. Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted April 11, 2011 Author Share Posted April 11, 2011 I had my suspicions about that. One of the descriptors when buying sheet Copper is Oxygen Free. I'm assuming when you say "Real" charcoal your talking wood? About the Charcoal stick, how would I go about making one that is long enough and strong enough to stir a #8 Crucible? Can it have a unburned core or would that turn into a torch. What kind of flux do you recommend? I think I remember reading about people using glass as a plug to help reduce 02 absorption. Do you know anything about that? Thanks Thomas! Quote Link to comment Share on other sites More sharing options...
urnesBeast Posted April 11, 2011 Share Posted April 11, 2011 I asked my aluminum casting instructor about casting copper. He told me what I assume is an urban legend. The company that makes strike anywhere matches asked Edison for an innovation to save money in manufacturing. He pointed out there were two strike panels on each box. One was more than enough. They asked how he would like to be paid for this huge money saving idea. He said he would like a 2"x2"x2" perfectly cast cube of copper AND all the failed attempts. Casting copper well is so difficult that the scrap value of all the failures compensated him very well... Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 11, 2011 Share Posted April 11, 2011 Well Nassau Refining used to drop an entire large tree into the enormous vat of molten copper---they did recycling for the Bell System at that time. (I was told they actually owned a large piece of land just to assure their supply of large trees!) They of course could deal with all the water in molten metal issues. My casting has generally been under a pound for knife and sword fittings using my forge as the heat source so I can't help you with larger amounts. Have you visited backyardmetalcasting.com yet? My typical flux was borax and I liked to use the powdered charcoal but my crucible had a lid so easier to control the atmosphere in it. Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted April 12, 2011 Author Share Posted April 12, 2011 Why is it- whenever I want to try something new it turns out to be the challenge of a lifetime or some tool I don't have <_< Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted April 12, 2011 Author Share Posted April 12, 2011 I guess I'll experiementing for a while... Quote Link to comment Share on other sites More sharing options...
OddDuck Posted April 12, 2011 Share Posted April 12, 2011 Proper furnace atmosphere will help as well, run on the rich side to ensure a low oxygen environment. If you are looking for a cover, charcoal does work well, and will last a suprizingly long time in a rich furnace. Bottle glass and some borax work for a cover flux as well. To de-oxidize, stir like they said, or if the piece doesn't have to be perfectly pure copper, drop a zinc penny or two into the melt, the zinc will de-oxidize the copper as well. It casts okay, perhaps not quite as well as bronze or brass. Quote Link to comment Share on other sites More sharing options...
Bentiron1946 Posted April 14, 2011 Share Posted April 14, 2011 I worked with an archaeologist that who was somewhat short of common sense, any how he was wanting to do some experiments on the the Calcolithic and Early Bronze Age tooling and how well it worked. Being that he was short on experience with metal working experience he got a holt of me. He had a whole bucket full of scrap copper wire and wanted it cast up for his Calcolithic tools. It seemed that no matter what I tried I was very much on the short side of success until I started doing my own research. Those old boys in the Calcolithic Age were not working with pure copper but an impure form of copper that had a little bit of this and little bit of that in it, even arsnic. I suggest that if you really want to have success casting your pure copper that you make it impure. I mean by this add some lead, zinc, tin, silver or a touch of gold and have a good time playing like an early founder and experiment with your copper. Heck even make some Mokume-Gane, shakudo, shibuichi or traditional tin based bronze, just don't try to cast your scrap copper and expect to have a whole lot of wonderful success with it in that form. :P Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted April 14, 2011 Author Share Posted April 14, 2011 Thanks bentiron and oddduck- I'm going to start looking at defferent receipies for copper alloy and experiment a bit. I have a Crucible that came with the foundry gear and I know the old owner used it for bronze but I don't know what kind. So, if I ever do cast everdour I will need to get a new crucible anyway. I will want purity so I can match filler rod. Quote Link to comment Share on other sites More sharing options...
NickBalz Posted May 8, 2011 Share Posted May 8, 2011 Hi names Nick and casting cu based alloys is my real job, we use graphit as a cover and only use charcoal if ox is high also when we hold in a bigger furnace we nitrogen I think been some time sence I cast strait cu . I work at a d.c plant/ we cool the bars we make with water. Good cover of graphit through the melting process should work or it does with a 30,000# furnace any way good luck , my dad always told me I could do anything I put my head to , I have found that to be true BUT sometimes I bite off more than I can chew .Nick Quote Link to comment Share on other sites More sharing options...
Bentiron1946 Posted May 8, 2011 Share Posted May 8, 2011 Ninety-nine pure copper is a tricky beast at best and like Nick says when you working a 30,000# furnace, that is most likely electric, you can do is with a little more ease. If you have one of those nifty little electric furnaces that the jewelers use it can also probably be done with greater ease too but I just don't know, I have alway used a propane or natural gas fired melting furnace that I built myself. Fe, Yes, I have a different crucible for each type of metal I pour, gets expensive for awhile if you pour a lot of different ones, but then you figure out what gives the best results and you quit messing around with the metals that just don't give you a successful pour almost every time. You will still end up with clients that want a particular metal but by then you will already have a crucible for almost every one of the more common copper/brass/tin/zinc alloys on the market. Yes you will have the idiot that will bring you ten 5 gallon buckets of scrap brass, faucets, hose bibs, PRV, stops, etc., and want you to cast his sculpture out of that to save him/her some money but that will always end up costing you money over using one of the silicon bronzes, they pour so easy and no gas problems with them either. Just take their scrap to the salvage yard and get cash for it and then charge them the difference for the rest of silicon bronze, it will save so much hassle. I used to scrounge brass to pay for good casting metal, never throw away metal, the earth gave up her beauty for it so don't trash it. Quote Link to comment Share on other sites More sharing options...
Matt Bower Posted May 8, 2011 Share Posted May 8, 2011 I second the suggestion to sell the copper scrap and buy Si bronze with the proceeds. Quote Link to comment Share on other sites More sharing options...
NickBalz Posted May 9, 2011 Share Posted May 9, 2011 Any one ever try to mix cu and zn to make thier own brass? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 9, 2011 Share Posted May 9, 2011 Yes; but as brass is so easy to find in the scrap stream it's more often that I make my own 90:10 Bronze with pure copper and tin---for use in medieval replicas. Modern pennies are a nice size zinc bit to make small amounts of brass with. Calculate how many you need of them and pure copper. melt the copper *first* add the zinc---it will flare at molten copper temps---allow for loss! Stir and pour ASAP! Note that molten metals have their own safety rules---you drop a piece of hot steel it will hit the floor. You drop a bit of molten metal and it may hit the floor and come back up at you! You drip a little sweat on hot steel and nothing happens. *1* drop of sweat in a mold can result in death when casting metals! Also the fume dangers are there too. Zinc shakes are to be avoided at all possible and let us not forget the scary days when founders used to get arsenic prescriptions for the weekends so they didn't start getting the shakes. Quote Link to comment Share on other sites More sharing options...
NickBalz Posted May 9, 2011 Share Posted May 9, 2011 Yes; but as brass is so easy to find in the scrap stream it's more often that I make my own 90:10 Bronze with pure copper and tin---for use in medieval replicas. Modern pennies are a nice size zinc bit to make small amounts of brass with. Calculate how many you need of them and pure copper. melt the copper *first* add the zinc---it will flare at molten copper temps---allow for loss! Stir and pour ASAP! Note that molten metals have their own safety rules---you drop a piece of hot steel it will hit the floor. You drop a bit of molten metal and it may hit the floor and come back up at you! You drip a little sweat on hot steel and nothing happens. *1* drop of sweat in a mold can result in death when casting metals! Also the fume dangers are there too. Zinc shakes are to be avoided at all possible and let us not forget the scary days when founders used to get arsenic prescriptions for the weekends so they didn't start getting the shakes. yes yes yes never more right on the drop of sweat , one drop will make a nice sized blow when molten metal hits you it hurts !! Quote Link to comment Share on other sites More sharing options...
Bentiron1946 Posted May 9, 2011 Share Posted May 9, 2011 This one fellow that I was teaching the rudiments of casting to just never seemed to catch on for the necessity of preheating metal before putting it into a cruible of motlen metal. You want to dry it of all condenstation and moisture. During most of the year out here, no problem, but during the winter moisture will collect on the metal and well it can be explosive when you add scrap sprues to the pot of molten metal. He just never seemed to catch on or he loved being sprayed with molten metal. I have come across an antique(?)tin coffee set for $5, coffee pot, sugar, creamer & tray, total weight about 6# at Goodwill Thrift Store, kind of bent up and I have thought of using them for making traditional bronze but they are worth more as a set than as raw material. They were made in the Dutch East Indies before WWII. They were easy to set straight again tin being so soft but it is so tempting to use them for raw material. Quote Link to comment Share on other sites More sharing options...
MattBower Posted May 10, 2011 Share Posted May 10, 2011 Posted before but always good: wet ingot mold. http://www.liveleak.com/view?i=93a_1251647793 Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 10, 2011 Share Posted May 10, 2011 Tin ingot is not that expensive and goes a long way in a 90:10 alloy http://www.rotometals.com/Tin-Ingot-s/27.htm?gclid=CNjxl6f4oJsCFSRPagod9mY5Cg Quote Link to comment Share on other sites More sharing options...
Bentiron1946 Posted May 11, 2011 Share Posted May 11, 2011 Thomas, It's about $63 to but that ingot! Way more tin than I need but if I use one of my pewter mugs of recent manufacture that is 98%tin, copper 0.5%, 1.5% bismuth I can get by for $0.99 about 8 ounces of material. Yes I know it not 99.8% pure tin but close enough as in hand grenades, horse shoes and small thermal nuclear devices. The coffee service I got from Goodwill is worth a couple of hundred dollars so my wife wont let me cut it up. For my excess metal mold I use an old cast iron cornbread pan that has the shape of ears of corn so I end up with these about one pound ingots of bronze. I always preheat it so I don't end up like those two idiots with metal going everywhere. Quote Link to comment Share on other sites More sharing options...
freeman Posted May 17, 2011 Share Posted May 17, 2011 Why is it- whenever I want to try something new it turns out to be the challenge of a lifetime or some tool I don't have Oh man, I know that feeling well. Last time I had that was after I decided making an astrolabe was totally within reason. My logic: if they where making them 1200 years ago how much simpler it must be to make one now with modern techniques. A set of engraving chisels off of ebay, $60 in wasted material, one book on trigonometry and several stab wounds later (from said engraving chisels) I've come to the conclusion that fabricating an F-16 would be a more straightforward task. Here's hoping your copper experiments turn out better. Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted May 17, 2011 Author Share Posted May 17, 2011 90:10 Bronze with pure copper and tin---for use in medieval replicas. Is this measured by weight or volume? I have pure Tin for Tinning some of the Copper I spin. I generate enough scrap, this could be the ticket.... Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 17, 2011 Share Posted May 17, 2011 They sell it by the pound and will sell you less than a full ingot so you can buy 1 pound for under US$20 and shipping is NOT $40! I think you read the "must order 4 pounds to get a full ingot" as a minimum order. I have ordered just a single pound of tin from them before! Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted May 17, 2011 Author Share Posted May 17, 2011 They sell it by the pound and will sell you less than a full ingot so you can buy 1 pound for under US$20 and shipping is NOT $40! I think you read the "must order 4 pounds to get a full ingot" as a minimum order. I have ordered just a single pound of tin from them before! Thomas- I was asking about the recipe... I have the tin :) Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 17, 2011 Share Posted May 17, 2011 I was replying to "Thomas, It's about $63 to but that ingot! Way more tin than I need" As for ratios it's by weight. Quote Link to comment Share on other sites More sharing options...
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