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Puuuuuuurrrrrrrge

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One of the major advantages of the diagonal heat exchanger boiler in the Lapera is that there is a separate water path to the group. This means that the water from the boiler is not used to actually make coffee. If you have ever seen the inside of a well-used boiler, you will know why this is a good thing. The major disadvantage of the diagonal heat exchanger boiler from a fabrication point of view is there is a separate water path to the group. The separate path requires a second chamber that passes through the boiler – a volume that pierces another volume. This means, topologically speaking, that instead of there being just an inside and an outside, there are two insides and one outside – three surfaces that have to be protected simultaneously during welding where they intersect. When welding from the outside things are fairly easy: cover all the holes, fill all the interiors with purge gas and the gas from the torch itself protects the exterior surface. But what if you want weld from the inside (which we do, because it’s waaay better, trust me on this)? One of the solutions is removing all of the oxygen from the room in which the welding is taking place. But this, oddly enough, is not very popular with the people doing the welding. Other solutions require some kind of localized, gas-filled shroud that covers the exterior of the parts being welded. This can be more or less complicated depending on the shape of the parts that are being assembled. The boiler is a bit on the complicated side of the shape scale, so the shrouds, which also have to fit in/around the jig that holds the parts, are a bit, well, tricky.

Cutaway of the boiler – one volume piercing another creating a separate path for fresh water to reach the group. (The casting is (unfortunately) not pink in real life. Were that it were.)

Shrouds in place to protect the outside of the inside of the inside.

The shroud for the lower end of the heat exchanger (HX) is straightforward-ish. The only minor complication is that the HX tube does not pass exactly through the central axis of the main boiler tube, so the radius cut through the shroud is not quite symmetrical. After welding an end cap onto a small section of square aluminum tubing, the radius cut is easy enough if you have a CNC mill. Which, lucky children that we are, we do.

Quite a few bits of turned and threaded lumps of brass and various adaptors later and, good-enough-for-not-very-close-friends-and-family-whose-company-you-don’t-particularly-enjoy-but-keep-asking-you-to-weld-this-piece-of-their-neighnour’s-friend’s-dishwasher notwithstanding, one lower end purge shroud.

Where things get a little more challenging is at the top end of the HX with the new boiler casting. Both of these purging shrouds, it has to be said, were a bit of an afterthought in that they were thought about after the alignment jig was built. Both of the shrouds could have (and should have) been integrated directly into the jigs themselves. Last time I had my eyes tested, I was shocked to fined out that I don’t have 20-20 foresight.

Not having the right size of tubing on hand, I thought it would be quick to weld a few scraps of angle together.

Yeah, well, not so much. I had forgotten just how hard it is to weld aluminum. It took an entire morning of failing to weld with much swearing, vaporizing of electrodes and grinding out of contaminated welds before I remembered that welding aluminum is like going to McDonalds: I go to McDonalds about once every four years in order to remind myself why I don’t go to McDonalds more often. Also akin to a trip to the Scottish restaurant, once it is in the past (and you machine away most of the mess you make) it is just a bad memory.

A perfect 60 degree angled cut through the not exactly perfect DIY square tubing.

Looks like something. Don’t know what yet. But it definitely needs a cap. Yup.

Now we just need a knife.

Sorry…
…This Old Tony.

And a couple of flanges (close your eyes if you don’t want to be exposed to the welds – but cut me some slack, it is just a jig for Pete’s sake).

Oh yeah, machining hides my sins.

And now for a hole and the clever bit.

Laperas have magnets too.

Thanks for reading!

1 – Syrup of prunes

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jig-jig

Aidan Heart’s somewhat unnecessarily controversial sculpture of the mythical figure of púca, half man, half horse – dancing a jig.

As promised, this week’s post is all about jigs (not about jig-jig, despite the title). Well, jigs and purging. When all the parts are finally made, checked, polished, rechecked and sterilized in the autoclave ready for surgery (only mild hyperbole), two more things have to happen before the magic moment when the arc strikes and two pieces of stainless steel become one: they have to held together in the correct alignment and all of the oxygen in the air surrounding the weld location has to displaced or purged – usually with another, inert, gas. This is where jigs and purging come in.

But before we get to the the fancy bits, first some ground-work.

Cutting the stainless tubing to rough length on Soco Xiānshēng. The 3-phase Soco gearhead cold saw, by far the highest quality tool in the building, used to be known as Soco-San but, it turns out, is actually Taiwanese, so this may have been cultural appropriation, inappropriate and/or just wrong. So even though Soco-San sounds better, Soco Xiānshēng it is.

The before: replete with sharp hairy edges, nasty burrs, greasy mill finish, dents and scratches.

The after: squared and chamfered on the lathe, polished and de-greased to within a nanometer of clean-room cleanliness.

Heat exchanger tubes and flange castings ready on deck.

The first alignment jig ensures that the side-to-side and axial orientation of the tube is correct with respect to the flange casting. Kissing cousins?

Now things start to get a little more elaborate: a dry run with test parts of the heat exchanger (HX) and main boiler tube alignment jig. This setup fixes the depth of the HX through the main boiler tube and ensures that the boiler tube is level and aligned with the bolt pattern on the group flange. Ever-ting gonna be nice’an straight.

So I promised purging as well, but I only got as far as jigs and I am already a day late on my deadline. I’m afraid you’ll just have to come back for more.

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Titanic Upgrade

HMS Titanic boilers1

The Titanic, according to my admittedly mildly-unprofessional research, had 24 of these gargantuan boilers, made by Harland & Wolff Shipyard in Belfast (I doff my hat to you and struggle to maintain control of my lower mandible), that collectively consumed 600 tons of coal a day (shoveled by 200 workers!) in order to maintain the ship at cruising speed. 600 tons. I’m gonna say that again: 600 tons. 15 Jumbo Jets. A day. Mind boggling. So to describe the Lapera boiler upgrade as Titanic is a bit of stretch. OTOH, the Titanic’s boilers were only in service for 4 days and 3 hours (if you include the brief period post-iceberg) so we are already well ahead in that regard.

So why a blog post about this? Well, the boiler has undergone a major design revision for the second edition and, as it is by far the most complicated part of the machine and is completely unseen hidden away inside, it deserves a little more narrative-intensive attention and continuity than the Gram can provide. This will require backing up a little so if you have been following the stream there will be a little repetition to allow the narration to catch up with the intervening flow of time (time only going the one way and all that (another corollary of that pesky Second Law of Thermodynamics)).

The biggest and invisibilest upgrade to the boiler is the change from 304 stainless to 316. 316 is generally and significantly superior to 304 in terms of corrosion resistance mostly because it contains a much higher proportion of nickel. The high nickel content makes it quite a bit more expensive than its baby brother. Which may, or may not, be a factor explaining its non-universality in coffee machine boilers. No judgements here. Just saying.

So on to some of the bits and pieces, of which there are a quite a few, that make up the beating heart of the Lapera machine. First up: the main boiler tubes. Cutting these tubes, or rather finding someone to cut them without screwing them up, has been, until recently, the second-greatest problem / source of irritation since the start of this project in 2016; second only in hassle-quotient to the foundry work. Here they are, cut on an completely over-kill bus-sized lathe this time around because I cannot, to save my life, find anyone with a laser tube cutter who will do this correctly. Done also, despite the 500% increase in the price of nickel in March and subsequent collapse/suspension of the London Metals Exchange where all the world’s nickel is traded. (The causes and ramifications of this is a fascinating story btw. At least to me.)

Close-up of the engraved logo. These are a whole other source of complexity as the final appearance of engraving is very dependent on maintaining a consistent depth of cut -which is extremely difficult to do on a solid that deviates at all from its Platonic ideal. This was trivial when the tubes were laser-cut. Don’t get me started.

Next but not least are the threaded inserts that are welded into each opening in the boiler wall to provide ports for all the comings and goings of two flavors of water phases. This package contains an infinite number of said inserts, which is surprising because it (ie. the package) fits comfortably on the table.

They seem to fit 😉 Who knew?

Ok, now that we are more or less caught up. Here is something new (and quite exciting if you are into that kind of thing) to end today’s post: a cast 316 stainless group flange. This casting replaces the original flange that was a built up from individual pieces of sheet metal, all of had to be cut, machined and then welded together. The neck angle is also integrated into the casting which promotes precision of the boiler weldment by a considerable degree. Oh boy, this is soooo much simpler and simpler is soooo much better.

A little QC and a few corrective measures on the all-important flange faces.

The next post will be about jigs and purging I think.


1 – advanceair.net

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Laying the keel

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“And I can recall our caravel:
a little wicker beetle shell
with four fine masts and lateen sails,
its bearings on Cair Paravel.” 2


The Gist.

We make things, unlikely things, in small quantities, mostly by hand, and in a place where it is expensive to do this. The second edition Lapera DS is available now for pre-sale and the price is $12k Canadian. This is a lot by any measure, but not, we feel, and if you understand the process, by any means excessive.

The Longer Version.

I grew up in England in a place where they used to build working sailing ships. It was on the estuary of a minor river and the boats were smallish, made of wood, and slightly dogged. The pubs had nautical names and low tide revealed a collection of rubber boots claimed from the unwise and unwary by the estuary mud. There was a rose-covered bower at the bottom of our garden made from an old rowing dinghy, its stern buried in the ground, and a mysterious sail loft, far larger than the surrounding houses, towered over the garden wall. All that was left of the industry along the waterfront was a collection of empty sheds, crumbling quays, collapsing slipways and a strong air of pathos – now of course all erased by rather unimaginative imitation Victorian housing estates, definitely colder, if not also sadder than what was there before. As with many other places in the West, industry, not to be confused with industriousness, has moved on: where I come from they don’t make much of anything anymore.

I like boats. You may have noticed. There are similar distinctions to be made in boat building as there are in the making of coffee machines. There is a world of difference between “a silent, sweet sailboat slipping through the cool water”3 and a hole in the water lined with wood. Unlike espresso machines (no matter how you feel about your morning coffee), boats have that edge of life-and-death about them: if the water is cold, if it is deep, and most especially if it is angry, you very much want to be in a tight ship and not a wood-lined hole. Both coffee machines and sailboats are outdated technology: one is essentially a steam engine and the other has, well, sails. Coffee machines however, unlike sailboats (beautiful and graceful as they may be), retain a deep relevance to contemporary society: rather more people drink coffee at work than sail to get there. Ultimately, both sailboats and coffee machines are cultural as well as technical objects, inextricably tied to their time and place and to the people who make and use them. How something is made, how deeply its maker understands it and how closely that person is connected to the people who will ultimately use it, are, in my view at least, important. Put simply, culture is difficult, if not impossible, to outsource.

The city of Montreal dates back to the French colonial fur trade and has always been heavily enmeshed in the textile industry. My first three studio spaces in Montreal were in former textile and fur lofts in the old part of the city. The building in Montreal’s Mile End, where Laperas are made, was a leather goods factory (which had been variously and previously: a car wash, a body and transmission shop, a gas station and a stable). Historically, Mile End served as a gateway to successive waves of European immigration. After the second world war, the textile industry grew rapidly until it drew a nearly twenty-thousand strong labour force from the mostly European diasporas (Jews, Greeks, Portuguese, Italians) of the immediate surrounding populations. As with many other kinds of manufacturing, low overseas labour costs coupled with dirt-cheap containerized shipping led at first to the slow decline and then the rapid collapse of the local needlework trade. The loss of tens of thousands of jobs almost overnight had a huge impact on the people who worked there, and left a ghost town of empty factories. Into that vacuum rushed the artists, tech startups and other post-industrial actors in search of cheap space. Now the main industry in the area (other than flat whites) is video games; as about as post-industrial as it gets. The vast flow of European immigrants has left its mark on the neighborhood in the form of churches and synagogues, bakeries and delis, the world’s best bagels (sorry New York, you’re just wrong) and, of course, proper coffee.

Da capo al fine is an Italian term (all the good ones are) in music, meaning “repeat from the beginning” (literally “from the head to the end”), or, as Humphrey Bogart actually didn’t say in Casablanca: “Play it again, Sam.” So, after a few months spent sweeping under the tables, sharpening the chisels and polishing the chandeliers, it is time to take it from the top. We have come full circle and are laying the keels of the second edition Lapera DS: twelve serial numbers from 0010 to 0021. Based on the experience gained during the production of the first edition and the feedback from the Founders’ Circle owners, this edition will have quite a few tweaks to improve, refine and better what can be improved, refined and bettered. So we’re playing it again, Sam, only a little bit better. The price, from beam to beam and stem to stern, is $12k Canadian. A lot, I know, but they don’t build ’em like this anymore. The edition should ship, if all goes well, in the first part of 2022.

For aforementioned unscientific and capricious reasons, the majority of this edition is already spoken for. There are still a few machines in search of a good home however, so please get in touch if you would like one. 

Thomas


(1) Howard Chapelle, 10 ft Rowing and Sailing Dinghy
(2) Joanna Newsom, Bridges and Balloons
(3) Annie Proulx, The Shipping News