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Dec / Jan 2014
Distilling at home PDF Print E-mail
Written by Allister van Mil   

Distilling at home

One step up from home brewing your own beer is distilling your own spirits, whether whisky, vodka or a liqueur. It’s okay to do this by law in New Zealand at home and for personal use although there are restrictions in Australia and many other countries.

Local home brew expert Allister van Mil of Home Brew West who has given Shed magazine readers expert guidance through the beer-brewing process now takes us through the process of distilling.

“I am using a pre-packaged distilling kit because the correct amount of high-quality sugar is available with activated carbon pellets in it. The pre-packaged yeasts have also been correctly calculated. This whole process takes about five days. The end point will be to make a whisky and a Japanese-style melon-flavoured liqueur. You will see distilling spirits is a little bit more involved than just mixing flavours with spirit.

“First you have to make what is called the wash. This is the mixture of sugar, water and yeast which ferments over a period of days and then goes into the still for further refining to get the high alcohol percentage which makes spirits.

Into a barrel goes some water. Then we top this up with hot water—I did it from the kettle—to the level of 25 litres and to a temperature of 40 degrees C. Check this with the thermometer

Read more in the Dec - Jan 2014 issue of The Shed

 
Raspberry Pi (RPi) camera PDF Print E-mail
Written by Mark Beckett   

Raspberry Pi (RPi) camera

Apart from a case, one of the best accessories to add to your Raspberry Pi (RPi) is a camera. The specs of the camera I am referring to are that it is a 5 megapixel still camera (2592x1944 pixels) or 1080 (30 fps) or 720 (60 fps) HD video, which plugs into the CSi connector on the RPI and uses very little power.

The software allows for a wide range of sharpness, contrast, brightness, saturation, ISO,  EV compensation, auto white balance, exposure mode, metering, along with output image type and effects. The video adds stabilisation and both allows time lapse (or time) and size to be set.

There are many projects using these, and some of the more interesting ones are

Tudor Theatre as a live camera on the throne.  http://www.raspberrypi.org/archives/4755

This was filmed using an RPi and camera http://www.dailymotion.com/video/x1255yy_sandiefield-road-demolition_webcam

The housing pics are here https://picasaweb.google.com/selsinork/RPiCamera

You would think twice about an expensive camera in this situation.

The low power and other features allow for the RPi and camera to be used for wildlife monitoring and removing the IR filter has been done.

http://www.raspberrypi.org/archives/5089

The camera company has now provided cameras without the IR filter, so we can expect more low-light projects to appear.

Read more in the Dec - Jan 2014 issue of The Shed

 
Casting aluminium wheels PDF Print E-mail
Written by Len Gale   

Casting aluminium wheels

Wheels are an important component to add character to a toy tractor, truck or loco. This raises the possibility of casting wheels in aluminium. Casting aluminium is not as complicated as it may seem; common sense is the main ingredient.

In the case of a tractor or traction engine which has two small and two much larger wheels, the contrast between the sizes is important. Further, the large wheels need to be wide but have thin tapered spokes.

This poses a problem: how to flow enough molten metal through the spokes to fill the rim? One way that may succeed is to extend the length of the sprue, (entry port) to increase the weight of molten metal above the cavity. Another solution is to add a 5 mm backing on the pattern. Thus the spokes will be formed, as well as this “extra cavity” and the rim will fill too.

Traditionally patterns have been made of close-grained wood. Metal and plastic patterns have advantages and now patterns can be generated on a 3D printer.

There are three types of pattern:

  • Split pattern. As the name suggests, this has two halves that align with two or more location-pins. Each half creates a cavity in the two parts of the mould. The two “boxes”—the cope (upper) and the drag—have location pins and corresponding holes that back up the location pins in the pattern.
  • Core pattern. This is a split pattern that has a “print” that allows for the in-plant of a firm piece of sand that makes it possible to cast an object with internal shapes that could not be machined.
  • Single pattern. This makes a cavity in the cope. There is no need for location between the cope and the drag. The sand in the drag is smoothed off to form the back of the casting.

All patterns need taper (draft)—from one degree to five degrees—to assist in removal.

Read more in the Dec - Jan 2014 issue of The Shed

 
Building a wooden sea kayak PDF Print E-mail
Written by Luke Spargo   

Building a wooden sea kayak

The wooden sea kayak I built is 5.2 metres long and is made from 4 mm-thick marine plywood. The design is constructed of four pairs of wooden panels, so eight panels in total, using the stitch-and-glue construction method (wire “stitches” together the plywood panels and the joints are glued). My final choice of materials included Meranti ply, epoxy, fibreglass tape, brushes and gloves etc.

I downloaded the plans for free from Guillemot Kayaks at http://guillemot-kayaks.com and the website also provided quite a bit of help for a first-timer which was useful. It was very generous of Nick Schade to make the plans available for free as I didn't really want to spend another $100 on top of everything else. This project was for NCEA Level 2 design technology course in Year 12 at Hutt International Boys school when I was 16. Through building this kayak, I won the Parapine ITM technology award for the student with the best practical ability, which was a bonus.

The first stage of the build was to set out the offsets from the plans onto the plywood. I took a few quick measurements of the sheets and found that they were not perfectly square so I had to rule a base line along the bottom of each sheet to take measurements from.

From this base line I measured out all the offset points on the plywood. To do this I cut a piece of MDF to use as a large square. This process is very time-consuming and once I had finished I double-checked every measurement again to make sure they were precise. One measurement incorrect at this stage would mean the panels would not fit together correctly.

It was a good thing I double-checked, too, because I did find a measurement that was wrong and a couple of others that were not as accurate as they should have been. Once all the points were plotted I had to use a flexible wooden batten to draw a fair curve between the points.

Read more in the Dec - Jan 2014 issue of The Shed

 
Coachbuilding art PDF Print E-mail
Written by Ray Cleaver   

Coachbuilding art

Coachbuilding with wood has been around for more than 500 years. The restoration of vintage cars is helping keep this craft alive in New Zealand—just—and there are only a few people here who still have these skills. One is Neil Carter of Normanby in South Taranaki. He specialises in restoring veteran cars (made before the end of 1918). These vehicles had wooden frames and bodies made by coachbuilders in the days when the horse and carriage ruled the highways.

We caught up with Neil, his skills and his current project: the complete restoration of the body of a 1906 Arrol Johnston, a car made in Scotland and one of only two left in the world. William Arrol, a Scottish engineer, was famous for building the massive Forth Bridge near Edinburgh in Scotland and he made cars from the 1890s to the 1930s. The Scottish owner of the car which is currently in Taranaki is sparing no expense to restore the vehicle to its original condition. The other existing model of this car is in a museum in Scotland.

The challenge of this job has been to build the complete wooden body of a 107-year-old horseless carriage from scratch, using only a drawing as a guide.

The project started with a bare chassis with a wheel in each corner and an old picture that Neil was given to work from. In the days before metal-bodied cars, the framing and skin of the car was all wood and Neil is building up the entire body.

Read more in the Dec - Jan 2014 issue of The Shed

 
An engine imagined PDF Print E-mail
Written by Roger Lacey   

An engine imagined

Puzzling out Richard Pearse’s engine

The riddle of Richard Pearse has been a source of fascination amongst anyone with an interest in New Zealand’s shed culture. How could a man on a remote South Canterbury farm manage to build a machine that could get airborne at around the same time that Orville and Wilbur Wright made their historic flight?

Consider this: Richard Pearse’s design has more in common with modern aircraft than the machine flown at Kittyhawk in 1903. Ailerons, a direct-drive propeller at the front and a tricycle undercarriage are all seen today on light aircraft.

So the questions remain:

  • Is Pearse’s design actually capable of controlled flight? and
  • Did Pearse fly but just didn’t consider his flights to be practical enough to be worthy of being called controlled flight?

Trying to get a better understanding of Pearse’s extraordinary work and put his design to the test has been a nine-year journey for retired automotive engineer Ivan Mudrovich who has built an aircraft based on the recovered engine remnants and Pearse’s 1906 patent applications.

In 1958, Ivan bought some equipment and started an engine reconditioning business from his garage at home before opening his own company that he ran until his retirement. While he built up a strong reputation for building high-performance speedway engines, he never got into racing.

“I may be mad but I’m not that mad” he says.

When Ivan sold his business in 2001, the pick of his equipment came home with him. Packed into his small garage are a lathe, mill, several cylinder boring machines, a piston grinder, a piston casting machine and a big-end borer converted to boring gudgeon pin holes. A rebuilt BSA motorbike engine sits on a bench waiting for Ivan to finish with his Pearse project.

In 2004, Ivan, not long into his retirement, had just got out of hospital from heart surgery when he was approached by a committee of Pearse enthusiasts to look at building a working model of Pearse’s two-cylinder engine. After a couple of meetings, Ivan quickly realised that his temperament was not suited to working with committees and if he was going to do it, it would be on his own terms and so he started his own project.

Ivan has gone a long way in unlocking the secrets of Richard Pearse’s designs and has built a double-acting, two-cylinder engine using the description from Pearse’s 1906 patent application and measurements from salvaged engine pieces.

It hasn’t been easy. Almost all of Pearse’s drawings have been lost, the only items that remain are his patent applications, some notes, newspaper articles and some mechanical relics.

Richard Pearse historian and biographer Gordon Ogilvie reported that in 1971 he excavated from a Lower Waitohi farm dump the irrigation-pipe cylinders from Richard Pearse’s rudimentary 2-cylinder, horizontally opposed, double-acting “oil engine”. In an address at the South Canterbury Museum in Timaru where the Richard Pearse Archives are housed, reported in The Press newspaper, he said the excavation was with the help of Maurice Cameron who had searched the farm 13 years earlier on behalf of George Bolt and recovered relics of one of Pearse’s four-cylinder engines with propeller and crankshaft.

As Pearse built several engines, including at least one for a motorbike, the pieces that were recovered from the dump were a bit of a mystery box. Discovering whether the parts were from working engines or discarded experiments was like attempting to complete a jigsaw with half the pieces missing, parts from other jigsaws thrown in and with the possibility that some of the original jigsaw had been modified and used for yet another jigsaw. However, Ivan has painstakingly gone through and tried to make sense of it all.

Read more in the Dec - Jan 2014 issue of The Shed