Thursday, 13 December 2012

Roundhouse Objects Conservation - Dec. 11 2012

December 13 2013

Metal Object Cleaning....Continued

One of the larger metal objects found at the railway roundhouse site in Kentville Nova Scotia is a wheel that was likely used to open and close a valve.  Perhaps, even, as part of a piece of steam equipment.  It came to the museum labelled as a brake wheel but the diameter is 22.5 centimetres which makes it quite a bit smaller than most brake wheels I have seen in photographs.  There are other clues to its possible usage that I will point out later.  It was heavily crusted with corrosion products (rust) so my effort was, as with other metal objects, to remove any loose material in preparation for applying a layer of wax to seal off the surface from moisture.  All material removed was saved in a sealed glass container.  Also, as before, the hope was to make clear any makers or other marks on the object.  There are some raised, embossed material possibly letters near the centre.  Of particular interest is what appears to be some small pieces of textiles (cloth) on the outside of the wheel and around the nut on one side of the short, threaded shaft running through the middle.  The opposite end of this shaft appears to be broken with a crack visible.  Was a cloth used to turn the wheel and torn or was the object thrown away along with some cloth?  We will likely never know.  Below are photographs of both sides of this object:

Wheel before cleaning with cracked bolt in centre
Wheel before cleaning with rusted nut in centre

Wheel material cleaned off and tools used.
The surface of the wheel had a sheen of grey and red corrosion some of which was very soft and easily came off with a toothbrush with hard bristles.  Quite a lot of larger crusted material was easily pried off with a scalpel.  There were a couple of bead shaped bumps to the right of the nut in the centre which were not removed.  They are reminiscent of material sprayed about during arc welding which I have observed in the past while helping my father with some of his welding projects.  The photograph to the right shows the tools and the material removed.  The textile (cloth) pieces can clearly be seen.

Wheel centre close-up showing faint lettering.
One of the benefits to this type of cleaning is the ability to bring out any marks found on the object.  In this case I was able to show the word Crane which is a maker of all sorts of equipment and tools plus the word Open with what looks like a line with a very faint arrow at the end.  The photograph to the right shows these faint marks.  Certainly, these marks imply it is a valve wheel rather than a brake wheel since some brake wheels usually have the words ON and OFF in different points along the wheel.

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