Lighthouses of Australia Inc

Restoring lighthouse artefacts

By John Ibbotson, Lighthouse author & photographer. All photos by John

Before...

... After

Lighthouses have been evolving for over 3,000 years. During that time there have been a number of major innovations that have had a significant effect on their evolution. From the structural point of view these have included the invention of window glass so that lantern rooms could be enclosed and the ability to build interlocking-stone, offshore towers. Then there was the development of the reflectors, the Fresnel optics and the mineral-oil based fuels, which provided a light that was reliable and could be seen from tens of miles away.

These improvements over the original Pharos of Alexandria lighthouse resulted in the classical lighthouse, a solid, indestructible tower, with tree trunk beams of light and which were operated and maintained by a group of hardy, almost mystical people, the lighthouse keepers. 

The next, but elusive step was to develop an unmanned capability that would not only reduce costs but allow lights to be installed in places, like buoys, where lighthouse keepers could not live. This final challenge was solved by a Swedish inventor, Gustav Dalen at the start of the 20th century. Dalen invented three items that allowed lighthouses to be automated and demanned. Although his inventions have been superseded by electric power and microchips it was Dalen who developed a way for this radical step to occur, a step that many lighthouse enthusiasts consider to have resulted in the demise of the true lighthouse.

It was recognised in the late 1800s that acetylene (produced when calcium carbide and water are mixed) was a cleaner, brighter and more reliable fuel than oil or kerosene for lighthouse lamps, but it was dangerous to transport and burning it 24 hours a day wasted too much fuel. Dalen overcame these difficulties by:

• Developing a method for storing acetylene so that it could be transported safely. This was achieved by dissolving the acetylene in acetone and then putting it in a cylinder that contained a porous mass of asbestos and diatomaceous earth.
• Inventing, in 1906, the ‘Dalen Flasher’ which was a device that only took gas during the flash of the light although a small pilot light was constantly burning. This reduced gas consumption by more than 80%.
• Inventing, in 1907, the ‘Sun Valve’, which turned off the flash portion of the cycle during daylight hours, thus reducing gas usage by a further 50%. In 1912 the Sun Valve earned him the Nobel Prize for Physics.

These three developments meant that lights only needed to be serviced once or twice a year with the result that lightships and many lighthouses could be demanned and that lit buoys could be deployed. Some of his later inventions also improved the reliability of the unmanned lights. These included an automatic mantle changer, a mixer for providing a constant and correct balance of air and gas and a rotating array that was turned by the pressure of the gas coming out of the cylinder.

Since becoming a lighthouse junkie I have always thought that having a (small) Fresnel lens, a flasher and a sun valve would be the ultimate lighthouse collectables to own. A few months ago I was very fortunate to be given a flasher and a sun valve. They were in good condition except that they had obviously spent a lot of time out in the weather and hence needed some restoration. The following is what I did to restore them so that they could be displayed.

Restoring the flasher

Before – the flasher with a dirty patina covering the copper and brass

After – the brass metalwork shines, whilst the newly painted red sections gleam

The first thing I did was to take a number of photographs of it so that I wouldn’t have pieces left over when it was reassembled. I then disassembled it, starting with the small gas tubes, then the burner frame and finally the two main sections.

The copper and brass were covered in a patina, which was probably a mixture of cuprous chloride (CuCl), cupric chloride (CuCl2) and possibly some cuprous sulphide (Cu2S) and cupric sulphide (CuS). To remove this I soaked the parts in a mixture of 10% vinegar and lemon juice, for a few hours. Adding 1-4% of thiourea to the mixture helped to minimise the etching of the brass. This loosened most of the patina so that it could be wiped off with fine steel wool. Unfortunately it still left a very fine residue on the surface. I tried to remove this with Brasso but it made no impression so I then carefully went over the brass with 800/1200 waterproof wet & dry abrasive paper. That worked exceptionally well without hurting any of the stamped details. After washing and drying, the brass was given two coats, using an aerosol or brush as appropriate, of White Knight Clear Guard. The painted portions were then given two coats of White Knight cherry-red gloss enamel, which matched the original colour amazingly well. 

I then re-assembled the flasher using the photographs as a guide. As the actual burner had a number of broken ceramic burner heads and as I had a spare burner I replaced t he original with my spare.

At the end of the whole process it was satisfying to find that I didn’t have any bits left over.

Before – the sun valve

After – the sun valve

Restoring the sun valve

This was in excellent condition except for the chromed conical top which was pitted and had a coating of the copper chlorides. It is possible to disassemble the sun valve but if it is old the glass sheath, even though it is quite thick tends to be quite brittle and can crack. As the glass already had a small hairline crack in it I decided that it would be best to do only a minimal restoration. This meant that the conical top could not be re-chromed. After removing the copper chlorides I spay painted it with automotive “chrome paint”. This gave a dull chrome finish instead of the original shiny chrome finish but the end result was quite acceptable.

Mounting bases

I then had a couple of round bases made at Southern Cross Trophies in 157 Victoria Parade, Collingwood. They were 200mm and 160mm in diameter respectively and 30mm thick. The flasher was screwed to the top of its base using its existing mounting holes on the base of the flasher. To mount the sun valve I had holes, 87mm apart drilled in the base that would allow two ˝” diameter 2-1/2” long bolts, with a Whitworth thread, to be countersunk into the base. (The holes, which were 85mm apart, were 14mm diameter with a 38mm diameter recess, 15mm deep.) These two bolts replaced the two original ˝” diameter 1-1/2” long levelling bolts in the base of the sun valve. Surprisingly getting the non-metric bolts was not a problem.

Now if there is someone out there with a small glass Fresnel lens they’d like to sell……..

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