Micro-welding replaces the metal that has been lost from a component, due to wear. Shown below are some of the clock parts I have micro-welded. The major advantage of the technique is that original parts can be given new life. The case studies below explore some of the benefits and the techniques involved.
Information on the micro-welding services I provide can be found on a separate page.
The photographs below show the machine and a close up of the electrode tip. Before the welding current is triggered, there is a short gas purge, which surrounds the electrode and the work, in inert gas (high purity Argon). Then the pulse of current is triggered, and at the same time the electrode retracts by approximately 5 mm. The duration of the current pulse can be varied as well as the amplitude.
The surface of the work and the filler rod melt and fuse into each other.
Some videos of the welder at work are shown on the manufacturer's website. As can be seen in the video, very little heat goes into the component being welded - notice that it does not burn the demonstrator's fingers.
My particular machine will weld gold, silver, stainless steel, steel and platinum. There is a special setting for silver, because of its very high heat conductivity. The pulse of current trails off gradually so the weld does not cool too quickly. Brass however, seems to be rather tricky, partly because of the zinc content. I haven’t tried copper or platinum yet.
Stainless steel can also be welded. Watch cases with worn strap lugs can be repaired.
My machine is supplied in this country by Sutton Tools in Birmingham, which is where I bought mine. (I am not on any commission for mentioning this machine, I am simply letting you know what I use and where it came from.)
When parts have worn, it is important to try and keep as much of the original material as possible.
It is very understandable that in the past people have done whatever they could to make a clock go again. This often resulted in new parts being made to replace the worn parts. However, there are more points to consider when working on clocks, than just being able to make them go again.
The National Trust’s policy for their clocks is to ensure that they last for a thousand years. This will not happen if parts are continually replaced. Unless great care is taken they might end up with a situation where the “old brush which has had five new heads and two new handles”. Is it still the same brush? It is not difficult to see that the answer is no.
Originality is the key to maintaining the value of an antique clock. Also, it is important that the rate of loss of antique clocks is reduced drastically. Although increasing rarity enhances the value of those which survive, it would be a shame if they were pushed any closer towards extinction.
There is growing excitement in the horological community about the role of micro-welding in the conservation of clocks. Horological repair methods traditionally involved the making of new parts to replace worn out ones. Whilst this will always be the case, micro-welding can drastically reduce the need for this.
Even without Microwelding technology, imaginative ways have been found to restore parts to full working order. For example, where a wheel has lost its teeth due to damage or wear, it was traditional to make a new wheel. Nowadays, horologists are thinking about making a ring of teeth to fit, rather like the idea of fitting a new steel rim onto a cartwheel. With some imagination, a lot of original material can be saved. Pinions in particular can benefit, by either making a new pinion head and mounting it on the original arbor, or by Micro-welding new material into the worn areas. Otherwise if a whole new wheel were to be made, the arbor and the wheel and its mounting collet would all be lost.
Traditional Longcase clocks were only made between approximately 1670 and 1870. This was a relatively short period in history, in which a finite number of clocks were made, and they cannot be replaced.
The present generation of clockmakers can help to ensure that there will be a demand for future generations of clockmakers, by properly looking after the clocks that remain.
An introductory article from the Horological Journal by Geoffrey Walker (FBHI), August 2008. (The Horological Journal is the official journal of the British Horological Institute.)
I am happy to microweld parts on your behalf - please see the microwelding services page for more information.
