General questions on pouring bronze

Discussion in 'General foundry chat' started by Drew, Feb 8, 2024.

  1. Drew

    Drew Lead

    Hello all,
    I hope some of you can offer some advice. I am a knife maker and I am planning to pour my own bronze for making guards, etc. I have never melted anything short of welding. I plan on making a simple ceramic fiber lined furnace to do my melting in. My goal is to end up with 3/4" x 1 1/2" finished bar stock. The length is not critical as I will be cutting it down to roughly 1" widths.

    What size crucible do you think would be most beneficial for this? I would like to build the furnace around the crucible.

    What size and type of container do I need to contain the pour? I'm not sure how much bronze will need to be milled away to get a clean bar. I'm sure there are many factors to that.

    I use a blown burner on my forge, but I have noticed that most videos I have watched with furnaces people tend to use naturally aspirated burners.
    Thanks,
    Drew
     
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Hi Drew and welcome to the forum.

    It might be helpful if you provided a little additional information.

    What bronze alloy?

    What kind of mold media are you planning to use? Green sand? Bound sand? Block Investment? Shell?

    So is that a fan forced propane burner or other?

    Is this the only thing you will ever cast or might there be other projects?

    Best,
    Kelly
     
  3. Drew

    Drew Lead

    Hi Kelly,
    Thanks for responding to my post.

    I plan on pouring silica bronze.

    The mold media I plan on using is a premade form. I'm not sure of the correct terminology. I think they are either made of steel or possibly graphite.

    Yes I will use a fan blower unless a venturi is a better option in this application.

    More than likely this will be all I will cast.

    Thanks,
    Andrew
     
  4. Drew

    Drew Lead

    I meant to say silicon bronze.
     
  5. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Silicon Bronze is one of the more friendly casting alloys

    I think you may have a little more research to do here. Neither of those are very practcial for a home foundry or bronzes. One of the four I listed are better candidates for a home gamer.

    Forced air will have higher heat potential than a naturally aspirated burner. Is propane the fuel?

    Building a furnace and all the learnings for casting is a long way to go for just for a small amount machine stock. Most people that want to cast machine stock have (free) scrap metal they want to convert to machine stock. Most people who cast want to make a net shape to avoid machining. Which are of the two you?

    Best,
    Kelly
     
  6. Drew

    Drew Lead

     
  7. OddDuck

    OddDuck Silver

    I think he means ingot molds. Sounds like he's just making bar stock to machine parts out of. Truthfully, if that's what you are going to do, you might be better served by purchasing pre-made, commercial barstock. Clean, on-dimension, and a more consistent grain structure that would probably give better machining results. If you are going to use shot or purchased ingots, you won't be saving much money after setup and fuel costs.
    Now, that being said, if you have a ready supply of scrap bronze, it might be worth your while and effort. It should be reasonably easy to make yourself a simple ingot/barstock mold out of steel, just make sure you give yourself plenty of draft (angle) in the walls of the mold to allow easy release of the ingot. Preheat any ingot mold thoroughly before use to drive any moisture out of your mold!!!
    If you really want to utilize the full power of the metalcasting process, make patterns of your near finished hardware and save a lot of machining and wasted swarf. Get some greensand or petrobond and learn the process.
     
  8. HT1

    HT1 Gold Banner Member

    Ive sand cast Historic traditional sword hardware in the past and still have the patterns, I'm not sure where the idea of Bronze came from sword hardware is Brass ( probably Cost) here is the patterns, simple 3D printed pieces took a fair amount of cleanup, but you should have all the tools

    IMG_9415.jpeg

    V/r HT1
     
    Riley Alfred likes this.
  9. mytwhyt

    mytwhyt Silver

  10. mytwhyt

    mytwhyt Silver

    Just bought one with 2 crucibles, for a friend 142$+tax. Now I've got to tell him. :eek:
     
  11. mytwhyt

    mytwhyt Silver

    Here's an example of what can be done using lost wax casting, especially if you plan on making a lot of knifes.. It's fast after you get the hang of it.. You can dip the handle in melted wax and have a place to start. Then an alcohol lamp an dental tool.
    I realize it's a big change of direction and would mean buying a casting machine and torch setup to melt the metal.. Sometimes i just get carried away , for that I do apologize. If you decide to try lost wax casting these types of things, I'm more than willing to help you along the way.
    Hollow pouring cup in wax.. | The Home Foundry
     

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