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Thread: New guy in WI

  1. #11
    Wow that's some good info! I like the idea of mixing a little copper into extruded aluminum or making aluminum bronze. Aluminum and copper are the two metals I have plenty of, so if there is a beneficial combination of those two, then I'm interested to try it. The zinc-aluminum alloy probably not though. I don't have a ton of zinc, I didn't know it needed that much. I also didn't know aluminum bronze was that strong, sounds like a good material for stuff. I'm not too concerned about machinability, I don't have a lathe or anything like that anyway. Gold color sounds pretty cool, also. Does it form a cool patina like bronze or copper does?

    I'll give some of your fluxing suggestions a try. I checked and I don't have any glass bottles like I thought, but tomorrow is thanksgiving so there will be plenty to grab.

    I do have 2 crucibles, the video has a lot of cuts so it's hard to tell.

    I'll avoid the brass then, I don't have much of it anyway. I do have a respirator, but no filters for zinc gasses or anything like that. It's mainly for dust and powders from wood working, though I do have some filters designed for welding. I think specifically they are for ozone created by the arc when mig welding, not gasses from welding galvanized steel, so they probably wouldn't work for zinc fumes from brass.

  2. #12
    from what Ive seen, I dont think the aluminum bronze will patina like bronze/brass as far as I know, so it'll just stay gold color forever, but I might be wrong. Ive never actually used the glass as a cover, so Im not sure how it works, but I do just use straight boric acid as soon as it starts to get molten, so that is what always worked for me.

    The home foundry isnt about what absoultely works and what doesnt, different people use different practices and different setups, so its mainly all about experimentation and finding what works for you.

  3. #13
    Senior Member Tobho Mott's Avatar
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    I have read that (solid) aluminum bronze is resistant to oxidization (and the opposite for molten al-bronze). I guess that and its hardness are reasons why it is sometimes used in industry for marine applications and for making landing gear parts. So if patination is possible at all, I would expect it to at least be trickier than with other bronzes. I do not know much about patinas though... Maybe with heat and the right chemicals?

    Quote Originally Posted by cae2100 View Post
    ...you can make an easier machinable aluminum bronze by adding cast aluminum rather than extruded aluminum, the silicon in it helps make it easier to machine...

    ...Another thing you could do is make aluminum bronze, which you just melt the copper, and add around 5-10% aluminum by weight to the melt, and it'll melt into it making an alloy that looks like gold, very very strong, but very hard to machine due to being so hard/strong. I was planning on making some myself and making some swords or knives with it, mainly because I thought a golden sword or golden knife would be very cool, expecially when it's around 6x harder than mild steel if it's forged also...
    Go for it, Cae! I hope you don't mind if I pick your brain about aluminum bronze a little while I am here since it seems like you know more than I do. The stuff you posted there is interesting, I did not know about the use of cast aluminum making the al-bronze easier to machine... I had been wondering if using cast al would have much effect on al-bronze's properties... I have some extruded aluminum I've been saving to make some aluminum bronze. I still will probably use that - I have no machine tools anyhow (unless a drill press counts?), and I want my al-bronze to be as tough as it can be.

    The reason I want to make my own is because A) last time I cast it I bought the bronze from metal supermarket and it was fairly pricey (seemed that way to me anyhow, first time shopping anywhere but kijiji for meltables) and B) it sounds like a lot of fun. I just need to find a whole bunch of copper scrap... I will most likely start with a heel of the left over purchased al-bronze alloy, then add the copper, then the aluminum.

    I am VERY interested in learning more about the forging you mentioned. I know Neil Burridge hammers the edges of his bronze age sword replicas to harden them, but it seems like that is one part of his process that doesn't seem to be video-documented on youtube or anywhere else I can find. also his stuff is cast in traditional tin bronze.

    Another member here foam-cast an al-bronze axe and hardened it by peening, but the only peening info I could find was a video related to hardening freshly sharpened steel scythes. Is the forging you are talking about a heat-related thing, or is it done cold as I have seen hinted at? My research on this has only led to conflicting findings. Any links or references would be greatly appreciated. I tried hammering the edges of my al-bronze axe (cold) a bit, but without any sort of anvil or forging experience it was difficult to do or to tell if it had much effect. I have read that aluminum bronze C954 can be hardened by heat treatment, which I gather is not a common characteristic of copper alloys, but I am pretty sure this would be outside my capabilities... at least for now. So I am looking at having to learn more about the process of hardening al-bronze by forging

    So that I am not totally hijacking Rufledt's thread here, here is a pic of my first and only aluminum bronze casting to date - an axe blade, just as an example of what this alloy (C95400) looks like. It isn't the greatest design for an axe, needs a wider cutting edge, the geometry is all wrong, and the back end is much better for just looking kinda badass than for doing any real work... But I am working on a better single-bit pattern to address these flaws and plan to make more. One of the guys from my annual no-wives no-kids hard-drinking canoe trip group wants to buy one (hard to ignore the shiny factor I guess - you can get a decent steel axe for much cheaper than the purchased al-bronze alone costs), and I want him to have one that he can really get some good use out of... I may also adjust the pattern for the first one to make it cut better, have a more useful adze-bit (maybe), and be more hatchet-sized. Maybe he will want a matching set!



    And here is a thigh-thick rock-hard hickory log that we cut in two with my axe during this year's trip. A lot of work, but the axe held its edge and that log burned all night. I've used the axe since then to fell several much softer small trees and such on my property as well.



    One thing that has not been mentioned here is that aluminum bronze is supposed to be tricky to cast since it really just wants to turn into dross. I was successful and I believe it was due to the way I designed the gating with reduced turbulence and avoiding air suction in mind - skinny tapered sprue with offset pouring basin, etc. as can be seen in sandrammer and olfoundryman's videos on youtube. I also added some charcoal dust from the bottom of an old bag of char left over from my charcoal furnace days, once into the cold crucible with the intitial charge, and again when I saw things were beginning to melt. I'd read that charcoal covers help steal oxygen that would otherwise react with the melt, as described earlier in this thread.

    Anyhow... good luck, post pictures, and welcome to the forum!

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

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  4. #14
    yea, the silicon in the castable does help make it a bit easier to machine, it requires a really sharp and sharp relief cutter to machine it either way. Aluminum bronze and aluminum-silicon bronze wants to work harden really easily, so you want as much of a knife action to everything as you can get so that it will just slice the metal off rather than pushing it off, which is completely opposite from an alloy like brass. I like to use HSS stuff with it but just make sure to either resharpen the bits to super sharp before trying to cut it and you dont want to use any that has been used in steel before unless it had been resharpened and rehoned. Its also why I decided to stray away from using carbide inserts for the lathe on it since they not only push the metal off when cutting, it also wants to run along the surface kinda burnishing the surface, which wants to work harden the al-bronze and makes it extremely hard to cut. I remember there was one person on here that had that same issue and went through like 3 carbide inserts just trying to machine down one casting due to that reason.

    Ive seen a few people actually casting little billets and forging it with a power hammer before, but Im not sure how it worked out for them. What I meant is to cold work harden it, al-bronze wants to work harden really easily, and by peening it with a hammer like you have done, it work hardens the edges and the more you use it, the harder it becomes.

    I know that pure al-bronze looks like gold, but when Ive looked around, al-silicon-bronze tends to have a slightly darker bronze color, but is very close to the same gold color, so just be warned of that. I was looking into al-si-bronze for making bushings/bearings for projects since it's more subjectable to wearing in on a hardened shaft, but after it's worn in, it work hardens and keeps it's shape and it's like running a hardened steel shaft in hardened bushing, so very little to no wear and a good bearing surface if kept oiled/greased.

  5. #15
    Senior Member Tobho Mott's Avatar
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    Thanks, that info is very much appreciated! Confirms some of what I have read elsewhere, but I may still have a few Q's...

    End derail though; I will maybe start a new thread for those.

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  6. #16
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    Welcome Rufled!

    Don't give up on trying the copper. When I first started melting metal that was all I was melting and was having LOTS of problems, I read lots of old (1930s/40s) books on non-ferrous casting and experimented with my set-up. Success came after many failures, now it's run of the mill stuff. I did a write up here http://www.alloyavenue.com/vb/showth...t+metal+moulds. Take a look it might help. Trust me, when you get a good pour you will be glad you stuck with it!

  7. #17
    thanks for the write up! I got plenty of charcoal, I'll have to try that process out. I also have some bottle glass ready to go. I gotta say, watching a bunch of propane burning foundry videos has me itching to make the switch, but i have a bunch of charcoal to burn through first!

    No worries about hijacking the thread, it's all info that i'm interested to read. Hijack away, I want to learn about aluminum bronze anyway since i have copper and aluminum in decent quantities.

  8. #18
    Success! Pictures incoming but I was able to get some small copper disks (not enough melted for a full muffin)! OddDuck was right on the money, I needed less air. I also needed more fuel. I think my crucible is too big to fit enough charcoal around it, but once it got hot I stuffed it with as much charcoal as I could manage, making the lid not even shut, and let it go at low air. Also, since the lid wasn't shut and it wasn't spraying sparks like a tornado of fire, I was able to add charcoal through the opening between the lid and the bucket so it continuously heated. I still don't think it was quite as hot as it needs, it BARELY mets the copper, but it did work. I also tried some of your flux suggestions and I think there is some glass I can't get out of the crucible, but I didn't end up with concretions of copper and crap like the first time I tried this. Thanks for the help!

    I still have some ideas to improve what I'm doing, but improvement is encouraging. next time I'm going to get a smaller crucible and pack in even more charcoal. also I might try to cut the copper into smaller bits and put more of it into the crucible at the start. Once I got the fuel/air thing worked out it got hot yellowish pretty consistently. The outside of the bucket sure got hotter than usual, too. My laser thermometer said the external temps last time during operation were around 150f, now it was more like 400! Also the plaster/sand mix is starting to break down, but that was expected. I'm thinking this bucket works great for aluminum, but an upgraded set up would probably help with copper. Melting copper is totally doable with this, though, which is kinda cool.

  9. #19
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    On your next furnace try to get some insulation between your metal container and the hot face. Ceramic wool rated at 2300 F or higher works good. You would be surprised how much heat you are losing through the sides of your furnace. Also a small puddle ( heel) that is the shape of the bottom of your crucible will speed up your melt time. Charcoal and coal need all the help they can get to get to melt temp before the fuel is consumed. I switched to propane and wont go back to coal.

  10. #20
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    U Tube is like television news. Most of it is bullshit. Those guys with their plaster furnaces should be put in prison. Plaster is useless in a furnace. A much better furnace for charcoal can be made from rammed up clay and sand.

    If you get some silicon and manganese, you could add it to your copper and have a really great casting alloy. Or some tin. Add that to your copper. Tin is a lot more expensive (19 dollars a pound) than silicon and manganese (3 dollars a pound) but it is more available.

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

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