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Thread: New guy in WI

  1. #21
    Plaster definitely is NOT a long term foundry material, that much is obvious now. It's more of a one-time use thing before it starts crumbling.

    Anyway, stuffed with charcoal it looks like this:



    Worlds biggest penny:



    got a couple of them



    Speaking of the next furnace, I see there is a whole section on this forum about building them. I think i know what i'm going to read next. The couple of books i've read talk a lot about different designs, but it seems focused on commercial sized operations or at least not small hobbyist ones.

  2. #22
    Also I have no idea why the pictures seem to come and go, same camera, same hosting site. Weird.

  3. #23
    I can't seem to find silicon that cheap, it appears to be sold by quote, which I assume means the suppliers are wholesalers to commercial operations, correct? I found the tin, though. Turning this copper into bronze would be pretty awesome if it makes for better casting. I have some aluminum but from what I read here and in some books, Al-bronze is tough stuff to cast, and tough is the last thing I need as a newbie. I think I need to find a local scrap dealer like you suggested and get some more aluminum. I gather little bits through the day in my job, but those are mainly heat sinks from circuit boards destined for the bin which is extruded. If I could get some silicon I could add it to that, but if I could just snag a few discarded cast aluminum wheels or something that would be awesome, I could set the copper aside while I practice a bit with something a bit less tough.

    I think next shot at it (next Sunday if it doesn't rain) I'm not going to waste so much time, so maybe I'll try to met more than just a small disk worth. Progress is slow with only a couple hours a week, but small progress is still progress!

  4. #24
    2 of your pics arent showing up again, it's like the permissions on the pictures are set to private or not set at all maybe or it just cant find the pictures. Ive always been able to find tin pretty easily, I just used lead free solder, it's usually 99.3% tin, 0.7% copper.

    Silicon is pretty difficult to next to impossible to find by itself, but try looking for ferrosilicon, luckygen on youtube has made homemade silicon bronze and shows using that to make it, he goes by ironsides on here. I believe there was someone that bought a bunch of it on here and was selling little bits on here in the for sale section a short while ago, maybe check there to see if they still have any.

    If you can melt and cast just plain copper like youve been messing with, aluminum bronze should be a piece of cake tbh. IMO, copper is one of the harddest to cast due to the oxidization and such when melting it, and youve already conquered that it seems. The gating and such for that stuff when doing sand molds, what people are talking about on here just means that the bottom of the sprue feeding into the mold isnt some massive hole, it's just really small like 1/2 inch and then tapered towards the top to enlarge it. I usually just stick a rod in the sand and when I want to taper it, just pack the sand around it like normal and just wiggle it around to do the taper part at the top. The bottom stays same size/shape, and the top goes to taper, easy as that.

    For a good book on building a more reliable casting furnace, I would look into dave gingery's books, it has alot of good info on making a furnace and sand casting techniques. Dave gingery also has alot of projects to build if you want some interesting things to make with the foundry ranging from random tools to a full metal lathe and milling machine.

    If you look at myfordboy on youtube, he has a very nice furnace and shows the build, and if I were building a furnace again, I would probably go with his design. His has a strong design, yet is very effecient due to the way it's made and uses a mixture of castable refractory and kaowool to make his furnace. I this his is under the name of building an oil fired furnace or something like that.

  5. #25
    Administrator Site Admin
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    That's kind of how I started. I built a charcoal furnace and began melting bronze in a steel crucible. That wasn't such a good idea, so I bought a real crucible. Then I got tired of charcoal and made an oil burner. It melted my furnace, so I bought some Mizzou and made a hot face. This is my first furnace, built in 2003. It has been added to and modified extensively. I still use it regularly.



    It has two inches of rammed up clay and sand with a one inch Mizzou hot face. I built a larger furnace using ceramic wool,



    but were I to ever build another furnace, I would do it this way, using the clay and sand with a hot face. It is heavy, but for me that's a plus. I don't like my furnace moving around when I am melting metal.

    Richard
    When I die, Heaven can wait—I want to go to McMaster-Carr.

  6. #26
    Thanks for the tips, ferrosilicon seems pretty affordable and much easier to find. Also, inspection of my ghetto foundry has revealed it is dying very quickly. I know copper needs a lot of heat and i was cranking this thing as hot as i possibly could, but there is serious crumbling happening after like 3 firings. I checked into the Dave Gingery books and the titles basically read like a list of tools and equipment I have always wanted to get but could never afford, so i'm definitely ordering those books. I like the idea of the books adding onto previous books with the foundry being the first project. Even if i never build a lathe i can at least read the book and dream about it, right? Books aren't expensive anyway and I like to read.

  7. #27
    Senior Member
    Join Date
    Jan 2012
    Location
    Buffalo, NY
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    Welcome Rufledt,
    Some of Gingery's books like The Charcoal Foundry are available on Kindle as well. His teaching is very simple and thorough. He covers a lot of ground in that one book. Note that it's called The Charcoal Foundry and not the Charcoal Furnace because he demonstrates how to make a foundry: furnace, tools, materials, etc. as well as basic patternmaking and sand casting techniques. Those demonstrations continue in the subsequent books.
    My first furnace was a charcoal furnace made from Gingery's book. Nothing too complicated, basically a bucket full of refractory cement with an air hole and a lid. I still use it but I started burning oil in it a couple of years ago as well. It's not ideal for burning oil because the tuyere comes in right at the bottom which creates some combustion issues, plus I had to chisel around the tuyere to get the angle for the burner tube to fit correctly.
    I recently started on a new furnace. I have the top cut off a half keg and have the lid lifting mechanism complete. I'm in the process of making forms for the lid. The furnace body will be a solid 2.5" layer of kastolite-30 insulating refractory but the lid will be a combination of refractory and kaowool like Myfordboy made for his furnace.
    This new furnace will allow me to melt copper based alloys and I may attempt cast iron as well at some point. My old furnace uses a 2200F refractory and has taken some real punishment mostly from burning coal in it, but I've cooked it pretty well with the oil burner too. The new one will have 3000f refractory which will be here in the next week or two. I'll start a build thread when I get a little further along.
    Be warned, this hobby is infectious. You may be incurable already!

    Pete

  8. #28
    I lucked into getting the gingery books much quicker than I thought and I've been doing some reading. He mentions parting powder as something to buy, specifically non-silica based powder because of silicosis (something I already fear after flintonapping for a couple years). The Ammen books also mention this, but Gingery is more specific in saying other powders like flour and talc absorb water and are not a good option. The sand I have is petrobond which is oil based, does that make a difference? Also, myfordboys videos show him using talc for parting powder as well as coating cores and his castings look awesome. Am I missing something here, or is it a case of different people having their own processes that they have found work for them (another thing that Ammen mentions a lot)?

    - - - Updated - - -

    Pretty sure I'm already incurable, Pete. That happened the moment I poured out my first aluminum muffin!

  9. #29
    Hi Rufledt
    DON'T use ferrosilicon with non ferrous metals, If my memory serves it's mainly for cast iron and steel hence it's name.
    That said, I believe it's iron content is very low & if what you are making is ornamental any possible weakening of the structure is of little or no consequence.
    The only time You're not following your nose is when your going backward!.......Andy (ME) .
    Have you filed in "Who do you think you are?" "War Grade Report" " My photo's"

  10. #30
    Ive always used baby powder for parting powder, and most of the commercial ones that Ive seen are really just talcum powder, or crushed up and powdered limestone. If you mull your sand and everything is really sticky like your petrobond, then baby powder/talc is perfectly fine and works great.

    I believe that some ferrosilicon has higher concentrations of iron in it, but most that Ive seen has 75-90% silicon to the rest iron for ferrosilicon, so I would check the ratio. if you look up the different grades of silicon bronze, expecially the older alloys, they all have a small percentage of iron in it, which if you used the ferrosilicon, it has it in it in around the same ratios really.

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