Toronto's Role in Lost-Wax History (and dubious patent claims)

Who knew that our own young city of Toronto played a part in the ancient technique of lost-wax casting? As I was researching the history of this technique, I discovered this:

"It  was in 1934 that a Danish engineer, Thoger Gronborg Jungersen, working with a firm of manufacturing jewellers in Toronto, devised the flexible rubber mould from which any required number of identical wax patterns can be obtained. This made  it  possible to produce substantial quantities  of  small castings possessing all the fine detail of the original master pattern."

Who was this T.G. Jungersen, and did he really invent the idea of using a rubber mould to produce multiple wax copies - a process we all follow today? In 1938, he received a patent for the following invention:

"A method of casting articles of jewelry of intricate design consisting in first producing a model of the article to be cast, then forming about said model a primary mould of a plastic material which will retain a lasting shape through subsequent treatment, then removing the model from the primary mould, then by centrifugal action forcing into the primary mould molten wax or other material of a low fusing point that will not injure the primary mould to form a pattern, and employing the patterns so made for the manufacture of casting moulds."

Jungersen's technique worked very well - as we know! - and many other jewellery companies starting using it. And he sued them. He won some cases, lost others, appealed them, was countersued, and then finally on January 3, 1949, in JUNGERSEN v. OSTBY & BARTON CO., etc etc. etc., the Supreme Court of the United States ruled on the matter. Here's what they said:

"...it is clear that the 'lost wax' process, the use of a flexible primary mould, and the use of centrifugal force were all old in the art of casting. The patentee claims that the centrifugal forcing of wax into the primary mould had never before been combined with the other features of his process. We think this fact is of no legal significance. Where centrifugal force was common as a means of introducing molten metal into the secondary mould, its use in an intermediate step to force molten wax into the primary mould was not an exemplification of inventive genius such as is necessary to render the patent valid. The patentee himself admitted that the same principle was employed in both steps. Thus, Jungersen employed in his claimed invention well known skills and practices in a manner and for a purpose long familiar in the field of casting. His claimed improvement is therefore not patentable."

Two judges dissented, but they were in the minority. Jungersen's patent was ruled invalid.

So, for a few years, Toronto could claim to be the home of the "lost-wax process using a flexible mould for multiple copy production", but the claim didn't stick. And today, in this little house in the central part of the city, we continue with our flexible moulds and lost-wax, and as we do we may sometimes think of Mr. Jungersen...

But not much.

I thought it was an amusing story. It seems ridiculous that the guy could think of patenting the procedure, but it worked for a few years anyway. What do I know?

This weekend: casting pewter round 2!