Mention the term “heavy industry” and the first thing to come to mind might well be the metal foundry. With immense machines and cauldrons of molten metal being shuttled about by crane and rail, the image of the foundry is like a scene from Dante’s Inferno, with fumes filling a vast impersonal factory, and sparks flying through the air. It looks like a dangerous place, as much to the soul as to the body, as workers file in each day to suffer mindlessly at the hearths and ladles, consumed in dirty, exhausting work even as it consumes them.

Things are not always as they appear, of course. While there’s no doubting the risks associated with working in a foundry such as the sprawling Renfrew works of Babcock and Wilcox Ltd. in the middle of the previous century, as the video below shows the work there was anything but mindless, and the products churned out by the millions from this factory and places like it throughout the world were critical to today’s technology.

Babcock and Wilcox, Ltd., the company featured in the classic of corporate promotion below, has a fascinating history. Started in America in the mid-1800s at a time when engineers pretty much only built engines, friends Stephen Wilcox and George Babcock teamed up to make a new and improved steam boiler. In a case of right time, right place, and right design, Babcock & Wilcox boilers were sold to factories making the switch from water power to steam. Thomas Edison even specified B&W boilers for his “Invention Factory” in Menlo Park, New Jersey; the famously irascible inventor wrote a letter praising the company for “the best boiler God has permitted man yet to make.”

By the late 1800s, B&W had opened an office in Glasgow, Scotland. By then the company had moved into the marine boiler market, with B&W boilers powering the ships of US president Teddy Roosevelt’s “Great White Fleet” at the turn of the century. A decade later, Babcock and Wilcox, Ltd. was incorporated, with offices in London and a foundry in Renfrew, Scotland. That foundry would grow with the business, and build not only the finished boilers but all the parts needed to make them and fit them into a ship or a power plant.

It’s fittings like these that we see being made in the film. The basic process of casting is simple enough to do at home; molten soda cans and packed sand molds will do a reasonable job. The Renfrew works operated at an entirely different scale, of course, and made cast iron parts rather than cast aluminum. And while the process was simple, the craftsmanship was anything but. The patternmakers stand out the most; with all the woodworking skills of fine cabinetmakers, they turned pine and mahogany into the complex patterns needed to form the molds from casting sand. The least defect would be reflected in the casting, so special care was paid to finishing the wood, and the patternmakers needed to be clever indeed to make some of the multipart patterns required for complex parts.

In addition to traditional, manual cope-and-drag casting for limited runs of special parts, the film shows more automated processes where parts are mass-produced quickly. Watching the ladles of molten iron being slung about is nerve-wracking, especially knowing that the only safety gear being used was the occasional cigarette.

Watching the film, I was struck by the thought that as low-tech as foundry operations seem from our vantage point, the products that came from them were anything but. First, the film was made in 1953, right about the time that both the world’s first commercial nuclear power plant, Calder Hall in England, and the world’s first nuclear submarine, the USS Nautilus, were being built using B&W boilers. Casting fittings and boilers for nuclear plants is cutting edge stuff, even if it starts with sand and molten metal.

Second, the scale of the operations going on in that plant means the logistics must have been incredible. Think about planning every last detail so that the right mix of metal is ready at just the right temperature for molds on a particular production line or custom shop. And we’re only seeing a sliver of the complexity of a foundry like Renfrew, which covered hundreds of acres in its heyday. Getting the whole plant running efficiently enough to be able to produce parts of high enough quality to be used in nuclear plants, and doing it without the help of computers and automation, is a testament to just high low-technology can reach.

I suspect that foundry work is quite satisfying, rather than mindless. The foundry I use when I want parts cast is run by a chap who seems very enthusiastic about the work, and seems keen to embrace one-offs and unusual pattterns.

There is the potential for a real synergy here: 3D printing is an ideal way to make foundry patterns, and it can make such things as multi-part patterns and backing pieces much more easily that hand-building from wood. Just one tip if 3D printing patterns, design in a hole in which to glue a wooden dowel with a small hole that the foundry man can put a wood-screw in to to withdraw the pattern from the sand. Wood screws do not take well in 3D printed mainly-air structures. You can make perfectly good patterns with rather a low infill ratio.

You need pattern draft, about 2 degrees. That’s a built-in tool in most CAD packages (including Fusion 360). Alternatively you can design from the parting face with tapered extrudes.

There are a few examples of 3D printed patterns, including a multi-part one for an undercut, in a Youtube video I made about making a new attachment for a milling machine. I don’t want to put in a direct link as that takes over the whole comments thread with a video window, but searching Youtube for XZHsDMJKJuk will find it.

One tricky part of 3D printing foundry-patterns is getting a good smooth surface finish. 2-part epoxy paint (such as the aptly-named “pattern coat” ) is one way, as it does not shrink back like conventional paint (as it cures rather than evaporates-off a solvent)

I’ve been 3d printing and casting the results in aluminum for quite a while. I usually dip my prints in liquid wax to get a smooth coating and to seal them enough that I can vacuum invest them. Which leads me to part two: using investment casting means you don’t have to deal with drawing out patterns or draft angles or all of that stuff. And what’s really lovely is that you can 3d print stuff in multiple pieces, like the old wooden patterns, but you don’t have to worry about needing to make them removable when you split the cope and drag, because you don’t have to. You make a big 3d printed chunk with some recesses in it, place in your cores, snap on the second half of the 3d print over the cores, invest the whole thing, burn it out, and mold, and you get everything the old foundry casters had, only simpler. Sure, it’s more expensive than greensand, but so is 3d printing.

It just occurred to me that I could make a really complicated core, like the water passages in an internal combustion engine head, using sodium silicate in a 3d printed core box (I’ve already done this) but with a piece of flexible steel cable, like bicycle brake cable, running through the middle of the core. That would make it more robust, and make removing it after casting easier since I could just yank on the cable and it’d tend to break up the core. It’s hard getting a core way out of the middle of a casting if you don’t have line-of-smashing-tool access, but this way I could get a hole all the way through and use it to saw away at anything remaining so I could use hot water/steam blown through the resulting hole to erode out any core that’s stuck.

Lost PLA casting can be done. 3D print the pattern in PLA with just one shell layer and minimal infill. Pack the sand tightly around it then pour in the molten metal. Works just like lost foam casting in sand.

I have actually doing that Lost HIPS casting at various infill levels works much better than pla. I even used part of it for my undergrad thesis.

B&W did quite a lot of ground breaking research as well. They really did change the world, and not only because of their “doesn’t explode like all the rest” boiler design. They came up with some fairly serious metallurgy – croloy steels that used less chromuim than SS does, and have better creep strength. If not for their work on efficiency, you’d be breathing a lot more coal exhaust. They were the first to go after – and get approved by the Navy and ASME types – that new innovation called “arc welding” – and even did MIG as submerged welding while everyone else was using rivets.It’s quite a story, and kind of a shame they got caught up in the asbestos thing – at the time they pioneered that, no one knew about the later cancer risks, but lawsuits basiclly destroyed that company without really helping the cancer victims – no treatment really works for that. They published a book yearly, called “Steam, its generation and use” which will tell you more about how complex a “simple part of a heat engine” really is. I had no idea there was that much to know about water alone! It’s worth finding that book in a used bookstore…

Such brawny work being done by men and one woman that have such a low BMI. Meat was still being rationed at that time. Roll up your sleeves and get ‘er done. Imagine the noise in these silent shots! This reminds me of all those educational films in school, the voice and shoots in completely separate worlds. Lots of dead air.

I spent some time working in the maintenance department of a brass foundry that primarily made plumbing parts. It was hot, dusty, dangerous, and extremely technical. The guys working the metal furnaces knew their jobs so well that they could produce a perfect recipe using a handful of this (zinc,usually), a handful of that (can’t remember what), a few chunks of leftover bronze, and a whole pile of brass ingots. Then, before pouring, that recipe was tested and always came out darn near perfect. Those guys looked rough, talked rough, and acted rough when off the foundry floor, but they had my utmost respect. They were absolute masters of their craft.

Great post. I am a retired Tool Die maker, mainly High Pressure Dies and Gravity Dies. Started in 1965, I am fairly conversant with 3D model making, the main advantage in the making of models using 3D is the speed patterns can be made. I would however describe foundry work as Black Art. Thanks again Brian

“Started in America in the mid-1800s at a time when engineers pretty much only built engines, friends Stephen Wilcox and George Babcock teamed up to make a new and improved steam boiler. ”

The total man hours involved is staggering… Particularly with small run parts. The skill levels shown at all levels but particularly the driving slot blade screws driven with hand cranks is humbling. The non flinching displayed with the intensity of sound and heat and raw lack of safety gear work is profound.

I work in the furnace room of a steel foundry, and am stand in spectrograph operator, and it is a fine art making a perfect melt! Its hot (imagine ambient temps sometimes 15-20c warmer than outside in mid summer) , noisy, smelly place and sand gets into everything! The first time i was ladleman was probably one of the scariest things ive encountered in my life! But it gets mental when a pattern fails and molten steel @ 1420c starts spurting out and you try and stem the flow with a clamp (we frame and clamp molds to the tracks) so you can try and save the job! Then its time to unclamp and push the jobs into huge shaker to reclaim the sand to be made into new patterns. Its never boring and keeps you on your toes!

I’ve been at the foot of multi hundred pound iron molds that blew open, spraying molten iron at my feet, jumping back as a pool of something like lava and cinders covers the ground.

I left off working in the foundry lab with engineering teams on the sand reclamation project and wondering about if worth somehow remelting and crushing to create “new” crystalline sand since the grains round over time and performance characteristics change. Fun with pristine dunes having the ideal sand and the communities wanting the dunes with the sand. The ideal of boring underground and proving Michigan can have the largest not only wooden dome structures underground didn’t fly either. Then seemed Africa maybe for cheap sand?

I read last week that the world consumes 50 Bn tons of sand per year, for concrete, glass, semiconductors, fracking, … Finding good sand, the “right” sand, is getting harder each year.

Yeah… an area of opportunity for sure I’m thinking. Makes new meaning for “stamp sand” maybe?

I’ve heard there is work being done on 3D electromagnetic molds somehow for certain materials though I’m not sure how advanced the detail is… seems like GE maybe… though I forget since was hearsay.

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Wondering if there is some sort of future tech that will be better or what? For now, the economics of sand looks like.

Buddy, you’re in luck, to crown a successful month in which we brokered the sale of both the Brooklyn Bridge, and Tower Bridge, London, my boss has authorised me to offer you the Sahara desert at the low low price of a buck fifty an acre…

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