Thing of the Week - Scones

Hey everybody what is going on?
I'm Roger in Technology and welcome to Thing of the Week for the Seventh of May 2015.

The discovery of fire brought mankind heat, protection and cooking but arguably it was the invention and refinement of the oven as a cooking space that revolutionised our relationship with fire.  Early ovens date back thirty thousand years and we've come a long way from the primitive pits used to cook mammoth. As far as I can tell, ever since then mankind has been striving to develop the ideal oven that cooks evenly to bake the perfect scone.

Ancient civilisations developed stone, brick, and clay ovens to radiate heat evenly, some employed smoke dome and chimney arrangements to use the heat of the smoke too. There are so many mechanisms and designs of oven over the centuries. From insulating clay ovens and metal agas that employed the huge heat capacity of their bodies, modern gas ovens allowed for precise fuel consumption to regulate temperature. But its the electric age that raised the bar by adding thermometer control. Thus the electric oven has taken its place as the final step in this long journey our civilisation has taken to reach peak scone.

The humble scone has existed in one form or another for centuries, and uses the most basic of cheap ingredients. Delicious sweet or savoury, they have become synonymous with cheese, cream teas or strawberries and bubbly. Whether you like butter, honey or fruit, the scone has a lot to offer as part of a balanced diet.

Top scones continue this tradition of self raising flour, butter, sugar and milk.  Often egg is employed to richen the mix, or an egg glaze is used for the same reason.  But do not trust a scone with egg, its a distraction tactic that just isn't needed on a good bake - the advice here is stick with the classic ingredients and use additions that theme and personalise your scone.

Fruit can be used, and often is. Sultanas are a classic for a reason, and they can be added to the mix or studded before baking. A little grated lemon zest offsets sultanas and lightens up the aroma and palate here.
Roast strawberries are a delicious addition too, although extra preparation is needed, and the addition of summer fruits give a fresh seasonal twist. Later in the year, orange and cinnamon can bring a delicious scone to life too.

Sifted flour should be mixed with sugar in a bowl. Typically only a tiny amount of sugar is used, even for sweet scones which can get their natural sweetness from fruit. Rub the butter in until you have breadcrumbs and slowly add the butter until you have the dough. Flatten it out and stamp some scones for baking at 220 degrees for fifteen minutes or until golden brown.
You can find details about proportions and recipes online, and should be able to find something that fits your tastes. I know less about baking than I do about history but even I can tell this recipe that has stood the test of time will be with us for centuries to come.

I enjoyed these scones warm with honey, which I can heartily recommend, as the subtle sweetness blends with the enticing aroma to produce a breathtaking masterpiece.  I hope you are inspired to get back to the simple roots of baking and experiment with the humble scone, as relevant in the 21st century as it was a thousand years ago.

Knife of the week

Hi guys and welcome to Roger In Technology.

This week I've picked a bit of steel to talk about. The invention of steel represented a cornerstone in technology for mankind, allowing tools, machines and weapons to be built to a higher standard and precision than ever before.

From blister steel, through crucible steel to the wide ranges of air, water and oil hardening steels we have today the world has been taken on a one way technological journey. Steel revolutionised all aspects of technology, and new technologies were invented to refine steelmaking.

This is a Gurka Kukri style knife dating to the mid twentieth Century. It's a versatile tool and deadly weapon with a proud military history from one of the most famed and feared military units in the world. 

It's about 34cm and has quite a weight to it because of the broad belly and the width of the spine. In fact this small steel blade weighs easily as much as some steel swords, and is as heavy as a generation of bronze age swords.

Pictured here is the "before" from a restoration work I'm doing. The blade itself has clearly suffered a lot in its life. The blade is dull, and while somebody has attempted to sharpen it they just didn't have the right tools. I'm going to grind a new edge on it and then clean it up with about a 1200 grit and hone the blade.

Kukris are traditionally made from leaf spring steel, which was readily available from scrap vehicles so we can take our best guess on the properties of the steel but to be honest the exact metallurgy isn't too important for the restore work I'm doing.

The blade is showing no scaling or flaking that would be evidence of heat damage, so I'm going to assume the temper is good and we don't have to heat treat it.  Heat treating a blade like this was a daunting task that I wouldn't look forward to, and I was somewhat relieved to see no evidence of overheating on the steel.

In Nepal, there are guys that quench the cutting edge with boiling water and allow the spine to carry its heat and temper the blade. I've got no desire to water quench this mystery steel as there is a good chance I'd crack it and ruin the piece. Actually, I've got no desire to heat-treat this at all, as I'd have to remove the handle and then I'm making a lot of work for myself.

There are some spots where water has go to it, but they appear to be surface marks and will polish right out with some high grit paper. The blade is fullered, which I didn't expect from a Kukri blade where I wouldn't have thought weight reduction was a consideration, but I'll admit to not knowing anything about this type of blade so it might not be that unusual.

Other than that, the blade shape is a little uneven and there is evidence that part it has been ground down. I'll try and get a nice even shape although that will mean a little more materials reduction than would be needed to just sharpen an edge and this brings me back to the temper. If its had a differential temper then the edge will be harder than the spine and I don't want to cut into the steel too much but it looks like I've got no choice.  There is also no point second guessing the properties of a mystery steel. I'll learn a little more by working the metal but for the most part it is what it is.

The handle is maybe a little long for a Kukri, but apparently this isn't unusual for service issue blades, and it appears to be a partial tang which again is traditional.  I first thought it was an integral bolster that had taken some damage but its clearly a second block and this is where the craftsmanship lets the blade down and seriously questions the authenticity of the piece.

I don't like the workmanship on the bolster, I don't like much like the decorative/mosaic pins on the handle either. They look out of place and more what I'd expect from a replica sold to tourists than a functional tool. There is an ugly boss on the pommel too, that can't be seen in this picture, but it doesn't scream quality. The chakmak is missing but the karda is a tiny thing that looks like its been stamped out of a sheet. No attention to detail and no craftsmanship on this which again is probably a bad sign.

Finally in my appraisal of the knife my mind keeps coming back to the uneven blade. Either its been used to hit rocks and somebody has ground those nicks out, or the steel is so soft it picked them up from normal use - so it'll be no good for a knife.  Since I'm already pretty certain it's not an authentic blade, I'm worried the quality of the steel is poor too.

My next step is to grind a new edge on it and sharpen it up. I'll use it to process firewood and see how well it holds an edge. If it survives some pretty rough treatment then I'll clean it up and get a dab of oil on it and it can be used as a camping and woods knife, or out in the garden to clear the brush and weeds.
If the blade goes dull quickly then it'll have more value polished up and looking pretty than cutting anything so I'll get it semi sharp and then polish the hell out of it. I can either mount it on something or sell it on to somebody who cares more about aesthetics than practicality.

The foundry is built

Project of the week is making a firebox suitable for a foundry that can be used to cast brass, bronze, or aluminium. .. and with a bit of elbow grease, the foundry has been built.

A refractory lining made of equal measures plaster of paris and sand has been used to line a 12 litre galvanised steel bucket.

The process is reasonably simple, although I'd recommend thinking twice and acting once in most cases as having to think and act at the same time can prove difficult.  I'd mostly planned the build and it went mostly to plan so I'm considering this a success.

Having not mixed plaster by hand before I will confess some initial concern that I'd make a lumpy mess that wouldn't be a smooth mix by the time it started to harden, but within 5-10 minutes it was smooth enough that I couldn't feel any lumps with my fingers and I decided it was time to pour.

The centre space for the fire was formed easily enough and with only a little fuss and bother, and the mix solidified up reasonably quickly once its fifteen to twenty minutes was up so all in all the timing was pretty good.

The finished product, or about as finished as it'll get tonight.  My reservation is that I should have made more lining material so that the firebox is deeper. I'd want it higher up the sides and deeper on the base.

The measurements looked good on paper, and I did a test run with water to work out how many measuring buckets of water fill the steel bucket. So I expected the volume of the lining to be spot on, but the drymix doesn't pack like water and the overall mix was about 30% smaller that I'd expected. The lesson learned, of course, is that I can afford to mix too much and tip some away but not having enough is a bit of a pain.

The firebox looks large enough to get a good charcoal burn and well big enough to work on small projects like tools or knives.

The mix stays butter soft for a long time, and I was in too much of a hurry to get the holesaw out and get the blast hole cut. Next time - if there is a next time - I'll be happy to wait a half hour or so before cutting. The steel is pretty thin and offers little resistance, and while you want to cut the mix quickly I didn't have to put myself in a rush to do it.

More news as it breaks, but with the bank holiday approaching I should be able to fire this up and see how it performs.

Proper Preparation and Planning

Preparation and Planning
While I'm not getting much project time in at the moment, I'm not wasting the time I have in proper preparation and planning.

The first working fire is about to be built - I've got sand arriving tomorrow that I'll need for the refractory mix and I need to buy a hole cutter to make the blast so I should be able to go out this weekend and if the weather holds I'll put it all together.

My first working fire is a foundry that I'll repurpose for some hot metalwork. It'll be fine until I can build something bigger, and will let me make cast brass components that I may well need soon. To this end I also caved in and ordered a graphite crucible online, I think I'm going to make a steel one when I can but having "That crucible problem solved" for now is going to mean I can get stuck in.

I'm going to use a cheap air blower from an outdoor ship and see how hot the fire gets. Long term I've got plans for a peltier effect module to power the fan from the fire. But the first step is putting a blower on there and getting a feel for how much air it needs to get a good burn.

Patio Paving
After making a few sketches and standing in the space, I'm pretty much sold on a patio space 15" wide and 18" deep, with two benches and a circular firepit around 3" in diameter.  This second firepit will be mostly for heat and show, but I want to be able to cook on it so a good first project for the working fire will be making a rotary spit.

Practical Project
The rotary spit will start as a simple A-Frame and crank handle, but if I want to spend two hours cooking a chicken I'm going to need to automate that rotation and the blog comes full circle to Roger in Technology.

Presenting Peltier 
The three engines I'm considering are all quite different in their construction and maintenance, and each with its pros and cons. The first is to use it as an excuse to make a peltier generator, which is a remarkably good project to start now, especially if I want to use it to power a fan later on.
The simple construction is a metal squarebar with a peltier device and heatsink on. The squarebar can be staked into the firepit at an angle, with the heatsink off to the side. And then I'll run an electric motor on a belt drive to turn the spit.

The peltier solution is nice, but it'll be difficult to get much current without a reasonably large array of peltier effect generators and a large heatsink. I don't know how much current I need to generate the torque to rotate a chicken. In fact, I don't even know how much torque you need to rotate a chicken so I could test this with some 9V or 4.5V DC motors and see if they are likely to be up to the task.

Piston Power
While the peltier might not work, the age of steam has me covered. I know I can build a steam engine with a boiler I can place in a cooking fire that will have much than enough power available - so specifically I can build a very small steam engine that will do the job.

It's a little fiddly to have a steam boiler in the fire with brass pipes leading to a steam regulator and crankshaft setup. My concern is that I have two unique units connected by brass pipes, and the pipes will bend and break.

The next option here is an external combustion Stirling engine. Relying on the expansion and compression of the working fluid, the stirling could probably be a single unit. Like the others it would sit on the edge of the firepit. Its probably harder to construct than the steam, but doesn't need as much pressure in the boiler and feels like a safer bet.  I find the stirling a more interesting design, and it should be very easy to maintain and run - needing little tending compared to the steam that might need me to look after the boiler.

Practical problems

Whatever the build, I need something that is easy to store. Its not going to live in the elements all year round, so I want something I can easily carry from the firepit and stow away to cool once the cooking is done.

Thanks for reading everybody, I know this wasn't really an action report and I don't have any pictures.  I'll get some pictures of the gear and the space before the build starts.

This blog was brought to you by the letter "P".

Firepit, Foundry and Forge.

Progress report on the technological terror I am creating.  This year, I'm in hardware mode instead of software.

Hardware this year doesn't mean valve amps and videocards, instead I'm going back a few thousand years and starting with the basics.  Aside from land clearance in the garden, the first construction is about to start - although land clearance and gardening is more challenge than you'd think.

Dakota Firepit

The first thought was to dig a dakota pit, and since I've uprooted some hedges I had a good starting hole to use that I've spent some time looking at.

The Dakota pit is a low-tech solution that I could build with stone age tools, and while I don't have any stone age tools I'm willing to improvise. It'll be enough to heat and beat some metal, and is a good cooking fire too.

I think I can get good airflow from a simple 12V DC brushless fan using an old chimney pot to duct air inwards, so I could upgrade the Dakota pit to get more heat and be a temporary forge fire. This blend of stone-age and modern technology pleases me.

However, the Dakota pit isn't a very visually appealing structure - its a hole in the ground full of fuel and ash at best - and at worse looks pretty naff. Ok, I'll be adding an electric chimney but it's still a hole in the ground. Rain will get to it too.

Its also fundamentally a floor pit which isn't a good height to work at. I'm not going to knock it - as a practical survival fire its amazing but for a domestic garden I can afford to go upmarket so I've been searching for practical alternatives.

Brake Drum Forge

The height of the Dakota pit is annoying, so I'm looking for a raised firebox at about waist high. Being portable is an advantage here because i'll be forging outside, but I'm going to want to store it in a shed to keep it safe from the elements.  Once I've built a forge house I can have a more permanent set-up, but I'm looking at getting started straight away so want something small.

A Brake Drum forge is easy to build, the parts are basically scrap metal and its reasonably portable. brake drums are galvanised, so can give off some fumes but I'll be outdoors and can probably deal with it. It's small, portable, and cheap and brake drums are the starting point for many blacksmiths.

Foundry
While the brake drum forge is probably the best starting project, there are some restrictions on its construction.  A Dakota pit can be dug with stone age tools that I could make myself, while a brake drum forge needs cutting, welding, and tooling.  Normally, practicing these skills is a great task but I want to avoid spending money on gear.  Also, the brake drum forge still makes your garden look like a scrap yard. There are also fumes from a brake drum and I'm not too into that.

The compromise is to make a storm-in-a-teacup, on this case a foundry-in-a-bucket.  I've got a twelve litre steel bucket - two and a half gallons - that I'm going to line with a refractory material and use as a blast furnace. With an air intake about halfway down I can use the same brushless 12V DC fan that'll get me between 30 and 50 cfm of airflow.  With 30 MJ/KG fuel I can get a thousand degrees in there and enough to liquidise brass.

Because the unit is contained in a bucket, it's super portable. It'll weigh in under 10 kilos (20lbs) and can be placed on a stand for working metal, or on the ground for stability if I'm heating a crucible.

Projects
I've got a few early projects in mind.  The foundry is one of the first milestones, and I should be able to 3D print patterns to make greensand molds from and cast shapes from brass. I'll have sand left over from making the refractory lining, and thats the principal ingredient in making casting sand.

Using it as a forge I should be able to make some fire tools, and a combination of cast parts and worked steel will make a rotisserie which will allow me to repurpose the whole thing as a cooking fire in time for BBQ season.  I guess I'll have to run the fire cooler for cooking - I'm not sure the melting point of chicken, but I'm pretty sure that a thousand degrees blast furnace will result in "well done".

The bucket foundry should be enough to work small steel and iron - tools, and some misc stuff. I'll be making nails with it for some woodwork projects. Kitchen hooks, bookends. Stuff.
It *might* be good for making chain, but there are complications and TBH I don't need any chain right now.
It'll be good for making knives, too, although I'll need a serious grinder for materials reduction and knives are a lot of work so its not a project to be taken lightly. There is a defunct lawnmower, so I'm thinking of taking the blade off and making a gardening machete from it. Reduce, Reuse, Recycle.

So overall, I'm hoping to get good use out of the bucket foundry. Pictures and videos are on their way.
Until then, Fly Casual.

Can I axe you a question?

Today was an axe day, destroying the garden - uncovering & discovering a large Mahonia trifoliolata which put up a fight with its super spiky spikes of vengeance.

Only afterwards did I learn that its edible berries ripen in the spring, and can be used to produce wine or as a fruit drink. Damn, had I known I would have left it standing until harvested.  Possibly I was distracted by the amazing bright yellow wood, which I'll keep, season and hopefully make something out of. But dang, I could have had some tasty berries.


Nonetheless, everything at the back save some unidentified reeds and the shed had been cut down and they are next. We don't have a key to the padlock on the shed, but its exterior construction is a wood that will not survive my industrious axework and it won't last once I focus my attention on it.   If it wasn't for the fact that everything has been chopped down, I'd be shopping for a bigger axe right now.


The wood I've collected isn't enough to make the benches from but I'll make a logpile and it'll feed the firepit on a summer evening. There is a tree that I've got my eye on, that might have to come down and then I'd be really tempted to make a bench from it rather than firewood.

The base on the shed isn't all that - Its bordered by pavers and to be honest I don't expect to uncover much more. So now I've got an 18x25 foot space - once the shed is cleared and the ground is dug - to build the forgehouse and patio space. The Forgehouse looks like around 9x15 foot or therabouts, with space for stock, fuel, hot and cold workbenches and all the regulars and comes in under the planning permission radar as long as a few simple checkboxes are ticked. It has to be non-combustable, but I was planning that anyway, and it has to have a decent floor and not have a bed in it. Also, 2.5M eaves and a 4M pitch, but those are way bigger than I need so it should be a breeze.

The hot workbench will be commercial firebrick on a sand base, and hopefully suitable for casting brass and other soft metals. The cold workbench will just be a thick wooden worksurface with a decent vice.

Meanwhile the patio has space for probably three benches, or two benches and a gazebo, and a firepit around three or four foot in diameter. This will be an earth or sand base for wood and charcoal burning, and I guess cooking over. This needs a plan. For all I know at the moment, I have a square space around 18x18 foot and want to have at least a bench and a firepit.

So plans are coming together. The base and patio are going to cost around three grand if I get contractors in, probably more given there is little to no access to the rear of the garden.  I can do it myself for around 750-1000 looking at the materials cost, or around half that for cheap ass paving, and I'm torn between just waving a wand and having somebody do it while I'm at work or plugging away at it with flesh, blood, sweat and tears.

Materials for the forgehouse are expensive in this part of the world, and I've got to choose between stone and brick which may end up being a very very difficult decision. The firebox, anvil and forge tools I need are cheap enough and everything beyond the basics I can make once there is a fire going.

It's a huge plan. Its a grand design. Its a lot of work. I'm starting to feel that this year will be the groundwork and learning year and the construction might not be finished until after the winter.

Starting Hardware mode.

Hardware mode
Today saw the first in a revitalised project. As the winter washes away I find myself in hardware mode again, and itching to make - and break - all manner of things.

There is a space at the back of the garden that I can zone for outdoor projects, and I want to do some ironwork so naturally bought a woodsaw and hatchet.  Between those and some good garden shears I've been able to start the land clearance I'll need before the garden bursts into life with the upcoming spring growth.

It's a dependency satisfying side-quest, a matter of tracing the cause-and-effect back until I get from the ideal set-up to the status quo.  And the status quo is an overgrown area, a vegetable plot and a garden shed.

The Space
We're fortunate enough to have a bit of space at the back of the house, and the rear portion of it looks ideal for a toolshed. The entire width of the garden is about 25 feet, and in the back portion of that stands a garden shed, a vegetable plot and some unused land.  The rear of the property is a brick wall, one side is a 4" high fence with some bushes and the right side is 8" evergreen hedges and some trees.

That gives me an area about 25x18 feet, with a 6" brick wall along the long edge. I intend to replace the dilapidated old shed with a stone tool shed with a solid workbench, fire-pit and small anvil on a solid block.  I'm going to need a solid base on probably that entire area, which means digging it up.

So... naturally if I want to heat & beat the first step was to do some gardening. Raze the bushes so I can dig the earth to lay a concrete base to build a tool shed on. Then I'll be setup for metalworking. I'm thinking of keeping enough space for some seating - a couple of benches, but I might make those myself once I've got some toolworking space.  And to be honest if I'm making a bench, I'll probably make my own nails at the forge.

There are plenty of other hardware projects that'll go alongside this. The question of a smelting fire and crucible have come up.  We had a crucible at the forge I as at before but I was never brave enough to try it.  It was also an antique, and probably against conservation guidelines to use it anyway.  But smelting brass or aluminium isn't so much hassle, and you need to get to about a thousand degrees which is quite achievable in a small fire and I'm game.

So, that's hardware mode. It's a weekend project, and I'll try and get some "before" pictures taken so we can document the transformation.