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Thread: Melt & cast copper at home?

  1. #1
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    Default Melt & cast copper at home?

    The copper riveting process for my skiff is producing a lot of little copper nail cut offs (about half of each 2 nail get snipped). I was wondering about using this copper to cast a name plate for the boat?

    How difficult is it to melt and cast copper at home? I have a Mapp gas torch and I have access to a Oxy/Acetylene if needed. Could the copper be melted in the ladle offered by WB?

    http://www.woodenboatstore.com/prodi...mber=832%2D004

    Any help is appreciated. Thanks.

    Dave

  2. #2

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    Dave, check out the Techshop http://www.Techshop.ws/ they should be able to help with the casting questions and BEST of all they are only a few mile from you. They even have classes for sandcasting as well as ALL the toys that you might want to play with in most any shop.

  3. #3
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    Your torch will melt the copper. get a really good set of gloves, and the cast iron ladels should work fine. A good charcoal fire works if you have a blower. Conventional lost wax process works just fine. There are several good, short texts on the subject, I just happen to live near Alexandria, Virginia torpedo factory, which is full of such artisans.
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  4. #4
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    The oxy torch should melt it easily. The mapp won't get hot enough.

    Why spend $25 on a special ladle. Any old steel pan shoud work in a pinch. The copper melting well before the steel. Apply the flame from above.

    Remember, we're only talking small amounts, here. Keep in mind that I haven't done this and others may contradict but this seems reasonable to me.

    What kind of mold do you have in mind?

  5. #5
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    Quote Originally Posted by Jim Ledger View Post
    What kind of mold do you have in mind?
    I just want to make a small name plate, like this guy:



    I'm not trying to save the cost of buying that plate from WB ($14) I just want to salvage some of my copper scraps and have a try at some melting and casting. I thought it would make the name plate a bit more personal if I made it myself.

  6. #6
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    copper is pretty valuable these days, I dont throw away any, all goes in the bucket to take to the recycle yard for cash.

    lead is also up
    There's one rich man onboard and there's twentyfive poor men and they enjoy it more then the rich man does -Jim Kilroy when asked if yacht racing is a rich mans sport.

  7. #7
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    Make the name plate out of wax and just as fancy as you like. Then go to the web and search lost wax casting. If there is a school nearby that teaches these arts go to them. But making your pattern in wax is the way to go.

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    Yes I would buy the WB laddle. Use the oxy-actylene rig.
    The copper melts at about 1400 degrees.
    use a welding tip, not the cutting tip. Easy job.

    Make sure to use welding goggles leather jacket,welding gloves and good boots and jeans.

    Do not get the copper too hot. if it starts to turn collors back off a little on the heat. use a metal tool to scrape the slag off of the top of the molten metal.
    I love the smell of fresh cut plywood in the morning.

  9. #9
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    Quote Originally Posted by Jim Ledger View Post
    The oxy torch should melt it easily. The mapp won't get hot enough.

    Why spend $25 on a special ladle. Any old steel pan shoud work in a pinch. The copper melting well before the steel. Apply the flame from above.

    Remember, we're only talking small amounts, here. Keep in mind that I haven't done this and others may contradict but this seems reasonable to me.

    What kind of mold do you have in mind?
    Thats right, MAPP gas is only 1100 degrees, copper melts at about 1400 degrees. Some metal pans have so much surface area that a lot of heat is being lost. A small metal pan might be ok. Check how the handle is attached. I have seen aluminum rivets in some pans.
    aluminum melts at about 1100 degrees.
    Last edited by donald branscom; 08-04-2007 at 05:18 PM.
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  10. #10
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    Googleing melting point of copper I find 1980 degrees F. Some of the brasses and silver solders are much lower.

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    Quote Originally Posted by donald branscom View Post
    The copper melts at about 1400 degrees.
    That is 1400 Celcius ...not Fahreheit ....a lot hotter !
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  12. #12
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    1400 C equals 2552 F. Iron pours at that temp.

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    Here is some info from the book Casting Brass by C.W. Ammen (the book covers all copper alloys not just brass).

    "Pure copper castings free from gas porosity are extremely difficult to cast."

    The author goes on to talk about the extreme problems caused by oxidation during melting. Calcium boride is suggested as a deoxidizer in the melt.

    A suggested pouring temperature for light, thin objects in copper is 2350 degrees Fahrenheit.


    Who knows what alloy "copper" nails actually are but they might be fairly close to pure copper. Melting small pieces that have lots of surface area like you are talking about doing will probably increase the oxidation problems during melting.

    You should also keep in mind that copper is generally regarded as a material that is absolutely horrible to machine because it is so gummy and stringy. This might have an impact if you are planning to have the lettering engraved into the plate.

  14. #14
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    The amount of usable metal in a piece that is meted is less then you see. Because of the oxidation that acures as soon as that fresh layer of metal is exposed to the air, that surface is no longer truly coper. It's coper oxide. This goes down a little ways. I do save all bronze screws and fasteners when I am pouring for a non structural piece.At one point I had a large amount of fasteners pulled from boat repair jobs. I wanted to melt them down into ingots just for clutter removal sake and to clean the metal. That oxidized material gave very little usable metal. Alot of slag, A lot of fuel to melt, and a lot of time. I don't know how far the oxidized layer goes. But for arguments sake lets say it goes down 1/64 th. Which is probably high for new fasteners. On old bronze screws for example their could be no actual bronze in them. If one had a large block say 1 foot cubed. Then that 64 th. is of little consequence. But if you have cubic foot of little nail clippings then the majority will be oxidized material. Essentially all slag. Not worth it on certain pours. But for a small name plat that could work. And since these clippings are pretty new there should be some good metal in them. Just not the most efficient melt.
    Last edited by Don Victore; 08-05-2007 at 01:01 AM.
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  15. #15
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    To cut down on slag formation and facilitate the melt, use borax (from the laundry section of the supermarket) as a flux. To make it easier to cast add 10 to 15% lead-free solder. It is over 95% tin and you will have made bronze.

    /// Frank ///

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    I'm surprised that no one has mentioned this yet-- Molten copper ( therefore any of it's alloys- brass, bronze) gives off topic vapors. Be sure to do this in a very well ventilated area, preferably outdors.

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    I'm surprised that no one has mentioned **this** yet -- copper gets really green and funky in salt water, much worse than SB. So a nameplate made from copper would need to be heavily varnished/lacquered or you'd end up sanding the letters off after a few years.

    I know the feeling, as I also save the cutoff ends of my rivets/copper nails, but perhaps a SB or brass nameplate would be best, and use the copper for something else?
    "The enemies of reason have a certain blind look."
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  18. #18
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    You can always make your own alloy. Add 5 percent lead free solder to your pure copper and get tin bronze. Copper conductor and water tubing are also good sources of scrap copper.
    This web site I visit often someday I may do something with this too.
    http://www.backyardmetalcasting.com/gallery.html

  19. #19
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    I forget how it's actually done. However, time was all the yards would have a bucket of some kind of electrolyte they'd toss all their copper and bronze scrap into. It would decompose and that would be used as an additive to produce copper bottom paint. Maybe one of the old fossils in here remembers. Fleming, you awake?

  20. #20
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    Yeah, I guess while we're at it if you guys have any other ideas for what to do with scrap copper or bronze I'd like to hear it.

  21. #21
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    Casting your own nameplate is a worthy endeavor IF you really want to do some casting. But melting copper/BZ is much more demanding than a little lead in the WB Ladle- forget that as steel and iron for a melting pot does not have enough of a melt temp differential for melting these materials.
    But if you want to do it and only make small items there is a way. First get some reading on casting metals so you work safe, sane, and get results right off and not waste your time. Jewelery making books- Tim McCreight has several-CompleteMetalsmith is good if you already have welding/brazing experience. Jinks McGraths books I like best for beginner info and projects. There are many others and the Library is a good starting point.
    Buy a small ceramic melting dish with a handle for a nameplate sized project- some sources are Rio Grande-the major jeweler supply and will mail a catalog, Otto Frei is in the bay area, and Indian Jewelers Supply is cheaper and will mail Catalogs also. This melt dish is a $ 20 item. Cut your copper into small even size pieces -small melts faster-less oxidizing-keep your flame-on-metal time minimized. You want to be fast and efficient through the whole process. You use a 'reducing flame' which is acetylene rich to reduce the oxygen in the melt environment- a bit richer than the brazing flame even, and definitly not the high Ox welding flame. You MUST flux as mentioned before- borax as mentioned-or propritary casting fluxes.
    For a nameplate casting you can buy cuttlefish bone or Tufa lava and carve your item in this material-very soft- and this becomes the casting mould for an open pour. I doubt you will want to invest in the lost wax process for a nameplate . Also there is a small sand casting kit available which could be utilized for small boat rigging fittings in BZ as well- Indian Jewelers has this and Rio has some other options.
    If you have and use the oxy/act rig this is perfect for small melts in the dish mentioned. Practice a few melts and pours. Work safe and unhurried with good venting/exhaust. Leather Welding Garments advised- if you weld steel maybe you have them-cheap enough insurance. I use chaps and a jacket, gloves, and thick leather boots, welding goggles, and welders respirator.
    The cuttlefish/tufa molds are one-off methods. The cuttlefish has a fine grain to it. If you own the oxy rig you have already the major item for SMALL casting and with a bit of learning and tools can make use of your scrap.
    As building a wood rowing boat for exercize is more involved than in may seem to the layman, so to is casting a bit of copper/bronze. It is a great skill to develop though and can lead to the capacity to make other fittings. True Silver Brazing is also worth developing for bronze fab'ing.
    Good luck
    Last edited by Varna; 08-05-2007 at 10:21 PM. Reason: clarify and fix spelling

  22. #22
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    Hmm, well I guess it's not as easy as heat, melt pour huh? I'm still interested in this but maybe I'll go ahead and pick up the WB plate and try the copper melting and casting later. Thanks for the info.

  23. #23
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    If it's a name plate you're wanting, why not just cut it out of a piece of scrap plate bronze or brass? I mean, really, as much as I revere our host, $14 for THAT is really over the top, dontcha think?

  24. #24
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    I found a piece of copper about 1 1/2 by about 2 on the inside of a computer. It was used as a heat sink. With a little heat and some careful application of a hammer you could probably reshape it to resemble a blank for a hand wrought name plate.

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