The latest National Heritage Ironworks Group (NHIG) seminar took place at the National Maritime Museum, Greenwich in November 2016. Hall Conservation were delighted to be able to take part in the day. This is an outline of the day’s second half.
The lunchtime break offered delegates the choice between a quick look around the museum and the chance to chat.
The first speaker after lunch was the entertaining Dana Goodburn-Brown. Dana spoke about her experiences examining archaeological finds uncovered at an Anglo Saxon buried ground in Sittingbourne. Dana runs the Anglo-Saxon CSI: Conservation Science Investigation project at Sittingbourne described as “an investigative conservation lab working on finds from an Anglo Saxon cemetery site.” The project is unusual in that it involves both professions and volunteers from the wider local community. Dana talked about the variety of techniques that she uses to identify and explore the artefacts uncovered. Dana provided what was perhaps the most striking slide of the day with a huge image of a water bear (aka a Tardigrade) a micro-animal that can survive for over 30 years without food or water.
Cardiff University’s Eric Norgren gave a presentation that focused on his extensive research into the effects of corrosion on wrought iron. He explored the differences between before and after conservation treatments.
Andrew Naylor’s talk looked at what can happen when metals with different properties are used together in close contact with each other. This can particularly be an issue in a damp environment where electro chemical corrosion can then occur. Andrew outlined an example from the history of the British war ship, HMS Alarm. HMS Alarm was launched in 1758 and was the first Royal Navy ship to have her hull sheathed in copper. The hull was later repaired with iron nails and when examined a few years later if was discovered that the combination of copper and iron in the salt water of the sea, had caused a severe decay in the state of the iron nails. Andrew showed how placing a simple insulation between the two different metals, copper and iron, could slow the process down.
David Starley gave a talk on material analysis and testing methods on ferrous metals. He gave examples of ways to date wrought iron as well as details of heat treatments on iron.
The last presentation of the day was by Hall Conservation’s own Brian Hall who took the delegates on a welcome whistle-stop look at repair issues relating to ferrous metals. Brian talked through examples from his own extensive experience in the Hall Conservation workshop including dealing with the effects of corrosion, stress, embrittlement, and rechrystallisation.
With the programme of short talks over, the delegates were able to enjoy viewing a film by Geoff Wallis showing the production of different kinds of cast iron and wrought iron.
After the film, Brian Hall lead the delegates over to the recently restored Queen’s House. There was time for a quick tour of the impressive building with particular focus on the famous Tulip Staircase. This four hundred year-old staircase is believed to be the first self-supporting staircase in Britain. It was recently restored by Hall Conservation as part of a wider 14-month restoration programme at the Queen’s House. Delegates enjoyed listening to Brian as he explained the process involved in matching the original smalt finish to the staircase. Smalt is powdered cobalt glass that was used as an alternative to blue paint because there was not a stable blue pigment available at that time.
With the tour over, the happy delegates headed off to sample some of Greenwich’s many fine watering holes.
Thank you to all the speakers on the day and to the many delegates who came from all over the UK to attend. Thank you also to the National Maritime Museum who did such a good job of hosting the event.
The National Heritage Ironwork Group (NHIG) website can be found at: www.nhig.org.uk
They welcome new members of all abilities and experience.
Find NHIG on twitter at: @Historiciron