Imagine my surprise when I learned that “bronze” does not refer only to the classic tin/copper alloy. Generally, it does, but when you’re talking about other alloys, they are also often called “bronzes” of various sorts.
For example, there is the rightly famous Japanese shakudō which is, variously, gold (2-7%) and copper, or silver and copper. Those are bronzes, and – as you probably guessed – can get pretty expensive to produce unless you are funded by your local daimyo, or Peter Thiel, or whatever.
I’ve been a bit stymied, lately, because I have two blades to produce collars for (habaki) and when I poured out some silver (argentium, which is – I think silver with a tiny bit of ? chromium) in it to reduce oxidation – my little block of material crumbled when I hammered on it. That is so incredibly frustrating, because you don’t have a blade collar, and you’re crawling around on the floor picking up little crumbs of silver, while all the off-cuts and grindings of steel are wreaking havoc on your kneecaps. Also, I have a certification from my doctor that says I am officially too old for that shit. (I turned 60 last November)
I decided to explore a few other alloys, including doing something truly dastardly: adding aluminum. Of course I am assuming you know that, once upon a time (before the bauxite/electrical reaction) naturally occurring aluminum was rare and more valuable than gold. There’s a helmet some prince or other had, made of aluminum, that was very very la dee da in its day, but nowadays most people would not shrug at it. I decided that alloys involving aluminum are actually very la dee da in Edo Period Japan, because aluminum was more precious than gold. So, I’d experiment with aluminum bronzes.
[This is actually from an earlier session but it all looks pretty much the same]
I use the small smelter, which was a couple hundred bucks, and is much more predictable and easier to work with than putting a crucible into a forge. Also, when you’re carrying a crucible to/from a forge there is a slight chance the crucible will crumble and you’ve just dropped some really hot stuff from a height. I’ve developed the habit of working close to the floor so things have a minimal distance to fall and splash. Molten metal splashes and sticks to shoes, floor tiles, skin, whatever. And it takes a while to cool.
Here, I was going to embed some video of a piece of AlCu in a vise getting whacked on with a forging hammer, but youtube has decided that the way to compete with TikTok is to turn everything into “reels” or whatever, which are low quality and not embeddable. Way to go, youtube! I hate the way that cloud services just change stuff for their convenience, and never bother to ask anyone about it. Anyhow, it looks like what you think it looks like: a piece of metal in a vice getting hammered on and bending grudgingly.
A small ingot of AlCu bronze.
It’s pretty rugged stuff and I’ll have to heat up the forge and see how it works hot.
Here’s another:
AlAg
The aluminum/silver bronze is also very promising. I polished it a bit on the grinder and it works to a fine finish, is tough, light, and pretty inexpensive. Silver is around $45/oz, which is not bad at all (gold is around $3000/oz for comparison, and aluminum is probably around $13/lb)
One of the reasons everything I do takes much longer than I want it to is because a) getting older, b) fewer fucks to power my process, c) a lot of steps involve collecting materials for a day of working at the hot forge – I can’t just fire up the forge for 3 minutes to beat on some aluminum. So things get batched, queued, and wind up sitting around soaked in WD-40 for a while.
Oops
I know how not to do that sort of thing, but I didn’t do the things I know I am supposed to do, so I burned myself. That was taken right after it happened, before it started to swell and hurt.
Poured the metal into the graphite mold, then thought “I should dunk this in cold water!” I had my welding mitts on, so it should be OK. I grabbed the mold, started heading toward the bucket (which is actually a vintage Mumm Champagne bucket) and halfway across, the heat started coming through my right hand mitt, with which I was holding the mold. No problem, I’ll just switch hands! Oops, the thumb of the left hand mitt had a big hole in it from contact with a grinding belt surface, and I was holding the mold with my bare hand. I switched it back real fast but not before my thumb started to emit a disconcerting amount of smoke and the smell of burned hair. Do keep track of the status of your safety equipment, if it’s a consumable!
As always, love reading about your adventures. I too turned 60 last year and understand screaming joints.
You have hair on your thumb? A hobbit in the woodpile, methinks…
Marcus! (said in the tone of voice my MiL used on Paul when she disapproved of some ativity he was engaged in, so “MaaAAAaarcus”!) Practical advice, keep the wounded area somewhat moisturised so the scab doesn’t pull or itch, but not so much you soften the surrounding skin. Use something scentless and thick. And yes I have experience although in my case it was only hot oil, into which I placed a spring roll carefully held between thumb and middle fingers. It wasn’t as bad as it could have been as thumb and finger nails turn out to be good at protecting the skin under them (who’d have thought it?), but it was pretty bad. I wasn’t sober at the time and it was only the expression on a friends face that clued me in, I’d burnt right through the nerves on the exposed skin. Do not deep fry if under the influence of sense altering substances.
The alloy looks good so far, I look forward to seeing the end result and any intervening process you care to show us.
I am a little older, 63. In the UK you know you have hit sixty as that is when the NHS starts sending out the shit collecting kit for your enjoyment. Apparently it is almost as effective as doing a colonoscopy, and a lot cheaper for mass surveillance purposes.
This post sent me on a web quest which disproved the legend I had been about to relay, that the builders of the Washington Monument capped it with aluminum as the most expensive (read, prestigious) durable metal available at the time.
Not so:
Much more metallurgy at the link.
We’re doing a lot of work on pressure relief at work. Today I had an exchange on Teams with our expert, went something like:
– That valve you want to use – is this one?
– Yes. The bronze one.
– What’s the body made of?
– Er… bronze? (sends picture of front of brochure which says “BRONZE” in big letters.
– Look at next page.
(looks at next page, where parts are labelled. Body is labelled with material of construction.)
– Ah, ok, it’s actually gunmetal.
– What is gunmetal?
(googles gunmetal)
– Turns out… bronze. Specifically: an alloy of copper, tin and zinc. Proportions vary but 88% copper, 8–10% tin, and 2–4% zinc is an approximation.
– Ah, OK.
So today we both learned “bronze” can mean a bunch of things. And now I’ve learned it some more. Thanks!
Remembering to be safe by using your safety procedures shouldn’t be difficult but, yeah. Hot things are hot, spinning metal cuts body parts easily.
I’m amazed I still exist.
A fun diversion concerning “bronze” is cymbals (as in drums and cymbals). All the big manufacturers (Paiste, Zildjian, UFIP, Sabian) supposedly have their own “special sauce” modification of the normal “cymbal bronze”. Each company also make several lines of cymbals from top end to beginner, each with its own formulation (which you can see by the color of the metal). Some of these manufacturers are amazingly good at product consistency. In my opinion, that would be Paiste (Swiss) and then UFIP (Italian). I can pick up two random Paiste 10″ Dark Energy splashes and they will sound nearly identical. Zildjian, not so much. And getting the metal right is only a part of it.
So, yeah, I like bronze.
So, how do you like the electric smelter?
Hazardous work. Someone could get your fingerprints from those high resolution hand photos and steal your identity.
Pierce R. Butler@#4:
Frishmuth quickly found that he could not use an ordinary sand mold for the casting and had to get an iron mold made. … When Frishmuth submitted his bill for the aluminum pyramid it was for $256.10. … Casey was quite upset.
I’m a little puzzled by that. It’s probably that sand casting wouldn’t give a sufficiently fine surface, but that’s what sandpaper and surface plates are for. Or, he could have surfaced the sand mold with a bit of investment plaster. Alternatively, since the melting temperature of aluminum is pretty low, he could have used a variety of other materials. My favorite thing to try would be 4 pieces of glass in a hole in a sand pile.Thermal shock might be a problem with that, though.
I remember when I visited the Edison museum in New Jersey, there was a thing about how Edison put out a challenge that he’d pay some amount for a perfect block of copper 1ft X 1ft X 1ft. Of course he never planned to pay – people would bring the blocks and he’d weigh them, or measure their water displacement, or measure them with a micrometer, and there was always some excuse to reject them. I was a kid when we went there, and I still remember distinctly thinking “what a dick.” And that was before I learned about his battle over AC/DC current with Nikola Tesla and his rather horrible marketing maneuvers.
I’ve read that bronze was originally an alloy of copper with arsenic!
Ouch!
I had to look up what is added to silver to make argentium, since I expect chromium would make it more brittle and much harder. Germanium is the metal added to argentium, which supposedly makes the silver more ductile. Since silver is already very ductile and easy to solder I assume the main advantage of argentium is the resistance to fire-scale and tarnishing.
I’m not clear on how your chunk of alloy is going to become a blade collar? Wouldn’t it be easier to just cast it in the shape/shapes you require, rather than forming it from an ingot?
I’ve never had a crucible crumble, (which sounds really scary) though I’ve had freshly cast investment blow up, or be dropped on its way to the quench. I can confirm that it starts vinyl composition floor tile on fire in approximately 2 seconds,
I am a bit younger at 57, and many of my daily activities involve crawling around on the floor, or the ground now that spring has finally arrived. Being able to see the tiny things and getting back up have definitely become more difficult as time passes. I can sympathize with the joint pain, my hip injury and psoas muscles really act up if I abuse them by spending hours doing squats, aka gardening. Of course, sitting in a chair with my legs crossed will also make my hip ache, so I guess that this aging thing just sucks.
Y’all are youngsters I’m pushing 70 . I do a very slow ballet warm up that lasts about 15 minutes while waiting for the bus . Usually start with Mandolin Rain . and finish with Wolf Totem by The Hu. Yes I can still kick my legs up over my head . 50 years ago I used to jump right out of bed and be able to do that but I have to warm up now . You do get older . Yoga also helps because it teaches you to relax muscles
Tethys@#12:
I’m not clear on how your chunk of alloy is going to become a blade collar? Wouldn’t it be easier to just cast it in the shape/shapes you require, rather than forming it from an ingot?
Well, traditionally, the Japanese like to shape stuff with many little hammer blows, instead of a rolling mill like a western jeweler. So, that’s how I’ve done it, because. I mean, I could just buy some silver bar from Rio Grande and saw a notch in it and bend it around the blade and, um, now I am wondering what the heck is wrong with me.
With respect to casting a piece – there’d still be a ton of filing to get it to fit the blade right, and it seems to fit better if you wrap it and braze it at the bottom.
I’ve had freshly cast investment blow up, or be dropped on its way to the quench
That sounds like a lot of drama, too!
jimf@#7:
Some of these manufacturers are amazingly good at product consistency. In my opinion, that would be Paiste (Swiss) and then UFIP (Italian). I can pick up two random Paiste 10″ Dark Energy splashes and they will sound nearly identical
Interesting. I suppose it starts with sourcing assay’d metals and then mixing consistently. I wonder if the brands that are less consistent-sounding are buying whatever mystery metal is cheap today.
I’ve seen a few bits of pan-making with copper on a lathe, and the idea of having an even slightly thin
saw bladepan blank spinning in a lathe anywhere me, is total nopesville.rsmith@#8:
So, how do you like the electric smelter?
It’s pretty nice – just charge it up and forget about it for a while, come back and you have a crucible full of molten gunk.
They make them with various maximum temperatures, up to 3000F. I wish I had sprung for the 3000F model so I could make small amounts of steel in it.
Before anyone asks, the way you do that is you set the crucible up, bring it to melting temperature, turn it off, and leave it overnight. I don’t think even Clarence Thomas’ donors could pay me enough to lift a few kg of molten steel in a graphite crucible over a concrete floor.
Steve Morrison@11> I vaguely remember reading something similar somewhere, but it also made some connection to arsenic-vapor-based neurological diseases/disabilities, and then further connecting that to Haphaestus (and maybe other mythological smiths I can’t remember?) being “lame” due to OSHA violations and some such…
I think that wikipedia rabbit hole also led to something about “aluminum bronze” or some such, but it was a while ago, and…
Bronze? Zeitgeisty!
[sorry, couldn’t resist]
In Czech, “bronze” nowadays means “any alloy consisting of mostly copper that is not named brass”. I do hope to make some bronze experiments too, one day. Aluminum bronzes are allegedly very shiny, malleable, and corrosion-resistant and the color can be adjusted by how much aluminum is in the copper. I hope to see you make something pretty out of this. I think that it might be possible to solder these bronzes with pewter-based solder, although it might be necessary to activate the surfaces with hydrochloric acid first – aluminum provides a passivation layer that prevents more than just oxidation – it might prevent brazing and soldering too. On the other hand, aluminum is one of those metals that readily cold-welds under pressure, so sufficiently clean surfaces might bond strong-ishly when just hammered together.
For high-heat dry burns like this, right after the burn before it starts to swell and develop bister, I use copious amounts of cold water for several minutes and then I put dry salt on top of the burn. It seems to reduce the swelling and development of the blister more than just cold water. It also might just be a coincidence that it worked for me several times, I am not recommending it to anyone else since I am not aware of any studies testing it and I of course do not burn myself on purpose just to make a statistical analysis of treated vs. untreated burn.
Marcus @ 15
I’ve seen a few bits of pan-making with copper on a lathe, and the idea of having an even slightly thin saw blade pan blank spinning in a lathe anywhere me, is total nopesville.
In that case, you might enjoy watching this video of the UFiP roto-casting process along with lathe work:
https://www.ufip.it/welcome-to-the-factory-tour/
Instead of roto-casting, most manufacturers use a stamping process (as does UFiP on some of their lines). Item to note: when you see the row upon row of finished cymbals on racks, keep in mind that top quality cymbals are expensive. A single 20″ ride can fetch over $500 and even small splash cymbals can be over $200. That room is a very expensive room (and I’m sure has a very strong floor).
Yikes on the thumb. That is really quite spectacular but must hurt like crazy.
That is so frustrating with the argentium. I would not have expected it to do that, but have very little experience with that particular metal alloy. I have a sheet of it I got a long time ago and now I am eyeing it suspiciously.
I hope you’ll show us how some of these alloys polish up. Making bronze with aluminum is a great idea, I’ll be interested to hear how it behaves and see how it looks.
So, this is what the AlCu bronze looks like, after some loving taps with a forging hammer.
Yes, it’s splitting at the top – not a good sign.
The main thing I was testing was how often I needed to quench it (to soften the metal) and the answer appears to be “after each heat” because the other piece crumbled quickly. I think that if I am reasonable with it (whacking it with a forging hammer is not being reasonable) I can probably work it pretty well.
ooh, interesting. seems like a serious rabbit hole you could get lost in
I’m keen to see the finished pieces
Marcus@22
it’s splitting at the top – not a good sign.
What do you think is causing it? Work hardening, aluminium oxide, other contaminants?
Aluminium bronzes often seem to contain iron and nickel as well. Maybe you need to adjust the “recipe” to make it easier to work.