19 February 2017

Old Oval Oak Overhaul

As blogged about previously, I bought an oak extending dining table online last year for $20.




 It had suffered a catastrophic breakdown into many pieces, the majority of which had been carefully kept by the previous owner for a number of years before he passed away.  Most of the joints in the table top had come apart and those that hadn't were on their way to doing so.  Using a hot air gun I separated the remaining hide glued joints.



After initially considering re-jointing all of the boards, I decided that it would be best to just clean up the edges with a wire brush and use a polyurethane glue to put them back together.  The boards have a unique double tongue edge joint but it had been damaged in places.




The polyurethane glue foams while setting, so has the ability to fill gaps to a limited degree.  An MDF former was used to allow even clamping pressure.  Boards were glued back together one at a time to ensure each joint was as flat as possible.



Several of the boards were too warped from years apart in the shed to be glued back together flat.



Relief cuts were made in the underside of the warped boards to allow them to flex enough to be straightened under clamping pressure.



One of the boards had a particularly bad split that needed to be completely re-jointed, meaning the table got slightly shorter and the curve no longer met smoothly. 



This was then re-shaped with chisels and planes...




...until it blended in as well as possible.  Large holes were filled with epoxy.



The turned legs had also suffered the same fate as the table top.  Several of the laminations had come apart and most had been saved in a tin by the previous owner.



These had all warped and so were flattened with a hand plane before being glued back on to the legs.



The middle removable section of the extending table top had been lost, so some new rough sawn American Oak was planed and squared and then resawn into two boards per plank on the bandsaw.


Once planed to the thickness of the fattest part of the original tabletop the new board were ready to be edge jointed together.  The original top varied from 18mm to 21mm thick, so the new central leaf was made 21mm.



The original leaves were held in place with dowels, glued on one side only.  A simple jig was made to transfer the dowel locations from the existing leaf to the new central leaf, and then to re-drill the holes on the remaining leaf to ensure a good fit.


Here is the jig clamped in place.  The end blocks ensure the dowels are in exactly the same location on each leaf.



Standard fluted beech dowels were sanded down on one end to allow the leaves to be pushed together comfortably.  The drill press was used to hold the dowels and a piece of emery cloth sanded the dowels down to an easy push fit.



The winding mechanism for extending the table had been lost and a quick look online revealed a new one would cost at least $400, so instead small blocks were attached to the underside and lengths of threaded rod used to clamp the leaves together.  On one end a nut was rebated into the block and Superglued in place, on the other end a wingnut clamped the leaves together.  Note in the photo a folded piece of paper was used as a spacer to allow the blocks to apply clamping pressure to the leaves once the paper was removed.


The ends of the oval table top still remained the weakest point, cantilevering out about 300mm, with the grain running parallel to the end.  Some oak brackets were made (with slotted holes to allow for wood movement) and fixed to the end rails.  This is not conventional joinery, but gives a little bit of insurance if someone sits on the end of the table.  The brackets were stained to match (a little too dark in this case).



Next, the tabletop was sanded back, with the new central leaf in place.  In the photo, the near leaf has been sanded, removing most of the original dark stain.



After further sanding, scraping and a light application of stain to the new central leaf, a 2lb cut of shellac was mixed up from orange shellac flakes.  Orange because that is the only type I could find, and purple methylated spirits because the local hardware store only sells the dyed variety.  This in effect adds a brown tint to the finish (orange + purple = burnt sienna / brown).

In future I will hunt down de-waxed blonde flakes and un-tinted 'denatured alcohol' as the Americans call it.


The legs were given three coats of shellac using a brush.



The tabletop was finished with a rubber or 'fad' - a wad of cotton wrapped in a linen cloth - about 12 coats in total, applied in figure eights and lubricated with some olive oil.



The finish is definitely not up to 'French polishing' standard - I have to learn the application technique a bit better - but is perfectly adequate for this somewhat rough-around-the-edges table.



Not bad for $20 anyway.












01 December 2016

Hawaii

A ladder engine from the Honolulu fire service - driver at the front, another person steering at the back and a surf board for... surfing fires?

Our Ford Mustang rental car.


Stairs near the summit of Diamond Head


20 November 2016

Sydney-cont

Long after they disappeared from London's tube network, the wooden escalator still makes an appearance at Museum Station in Sydney.

A somewhat militaristic sculpture in Hyde Park, near the Anzac Memorial.

17 November 2016

Sydney

Some observation from a brief visit.
A new seven storey timber framed building going up in Barangaroo.

Well used protected cycle lanes.

The Darling Harbour IMAX being demolished after only 20 years.

07 September 2016

Almost worthless

Travelling through Egypt in the 90's I was given some of these notes by a bank.  Despite appearances the denomination is not zero.  The Arabic symbol for the number 5 looks a bit like a zero or an egg.  This is a 5 piaster note, i.e. 5/100 of an Egyptian pound.  I literally couldn't give it away - shops would not accept it, so it came back home with me in my wallet as a souvenir.

Currently the Egyptian pound is worth NZ 15c so this note is less than a cent in value.


Nice picture though.  I think it is Queen Nefertiti (14th Century BCE).

25 August 2016

Airships - the Airlander 10 and others

Yesterday the world's largest aircraft, the Airlander 10 crashed during its second test flight in Cardington, Bedfordshire, causing damage to the passenger module. 


The project previously had cost and time overruns and technical issues before being bought off the US Army in 2013 by Hybrid Air Vehicles (one of the original subcontractors).  Despite the difficulties, it has great promise.  Due to the inert helium lifting gas it is relatively safe.  Nobody was hurt in the accident.

Photo by Philbobagshot via Wikimedia Commons


At 92m long it is huge but it is far from being the world's largest aircraft of all time.

The R100, launched in 1929 in Yorkshire, UK was a massive 219m long and actually flew to Cardington, Bedfordshire on its maiden voyage.  It was built by the private company Vickers, unlike its sister ship the R101, which was built by the British government.

The author Nevil Shute (A Town Like Alice, On the Beach) wrote extensively about his time as an engineer on the R100 in his autobiography Slide Rule, published in 1954, which I have a treasured copy.


US Library of Congress

In 1930 the R100 made a successful return trip across the Atlantic to Canada. 


R100 flying over Toronto
When its sister ship the R101 crashed in France later that year on its maiden voyage to India (killing 48 of the 54 people on board) the programme was scrapped.

Both the R100 and R101 are significantly smaller than that other well know airship the Hindenburg (at 245m long), but we all know what happened to that.


By Giant_planes_comparison.svg: Clem Tillier (clem AT tillier.net) derivative work: Timmymiller (Giant_planes_comparison.svg) [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons





17 August 2016

Middle East Part 3

In 1999, I crossed the border from Turkey into Syria and spent my first night in Aleppo at a hotel with dirty, blood stained sheets, dormitory style rooms and a filthy communal squat toilet (My travelling companions were keen to pay the absolute minimum for accommodation).

Despite this, travel in Syria was very safe and the people were friendly and hospitable.  We were invited by local Kurds to a wedding celebration at a neighbourhood hall and later explored the Citadel and the Great Mosque (both damaged in the current civil war).


View from the Citadel, Aleppo
From Aleppo, we travelled on to Hama and Homs, cities battered by the horrific ongoing conflict.  From Homs we took a dilapidated 1950's taxi in torrential rain out to Krak Des Chevaliers, a Crusader castle near the Lebanese border.


Krak Des Chevaliers, Syria
Then into the desert to the ruins of Palmyra, a city first established about 4000 years ago, but with artefacts found dating to 7500 BCE.  ISIS took control of Palmyra last year, destroyed many of the sites and looted the museum before the Syrian government recaptured the city in March this year.


Tower of Elahbel, Palmyra.  Destroyed in August 2015.

Palmyra, Syria
At the time (1999) I remember thinking how precarious these ruins were to earthquakes.  Little did I know that people would want to intentionally destroy them.  The physical destruction pales however, when compared to the human.  Palmyra's retired 81 year old antiquities chief Khaled Al-Assad was tortured for a month, then beheaded because he would not reveal the location of antiquities hidden from the conflict.

Palmyra, Syria



16 August 2016

Where does the heat go?

We have a relatively new (2011) timber framed house.  It was built to comply fully with the current New Zealand Building Code and has glass fibre wall and ceiling insulation and double glazed aluminium joinery - not particularly noteworthy when compared with colder parts of the world but quite suitable for New Zealand's temperate climate.  

Here were the outside and inside temperatures last night at about 10pm:



Our only source of heating is a 20kW wood burner, which we light on most winter evenings for about four hours.

Under the concrete floor I used 50mm of black polystyrene, which is slightly warmer than the standard white variety.

When designing the house I was aware that it was also good practice to insulate the vertical face of the perimeter foundations, however this is difficult to construct for a few reasons and is not often done in New Zealand.

Last night I used an infrared camera attachment on my phone to take some photos.



Here you can clearly see heat radiating from the non-thermally broken door and window frames, but also from the small exposed strip of foundation wall.



From the inside of the house you can also clearly see heat escaping around the perimeter of the floor.

The path for the heat loss is as follows:



This issue is going to be addressed in the near future.  We have a very comfortable home, but there is always room for improvement.

Incidentally, we have a concrete wall behind our wood burner which I designed as a form of heat storage.  This slowly heats up from the fire and then radiates the heat after the fire goes out.  This infrared photo was taken the next morning, about twelve hours after the embers had died.  The wall and tiled hearth are still radiating heat into the room despite the wood burner being cold.  







15 August 2016

Middle East Part 2

While travelling across Turkey towards Syria, we stopped in Cappadocia.  Towns like Goreme and Nevsehir are carved out of the surrounding soft volcanic rock.



The region was a refuge for people fleeing political turmoil right back to Roman times.  Then, it was Christians fleeing Roman persecution.  The area has many churches built into caves.




Currently there are about 2,700,000 Syrian refugees living in Turkey, compared with about 600,000 in Germany and less than 10,000 registered in the United Kingdom.



10 August 2016

Another break in transmission

More hand surgery and more plates and screws to fix the remainder of a very complex problem:  A 30 year old injury and surgery combined with spontaneous fusing of the wrist bone, coupled with another fracture of the thumb bone.  Fortunately I had an extremely good surgeon.



All going well I should be back to bike riding, woodworking, digging in the garden etc in six months or so.  In the mean time it's back to one handed typing.