Oct 6 2017

Film: How to make a 15th century beer tap

Bastian Asmus


Reconstruction: Functional tap from the early 15th century. Reconstruction: Early 15th century tap. The location is Zurich, Switzerland.

Some time ago I made a tap for a re-enactment brewer. I was already able to gain experience with the production of tap taps when I made my Aquamaniles. Therefore I decided to document the manufacturing process. Medieval taps often have a stylized cocks as a handle on the plug.  From the end of the Middle Ages taps or spigozs were made by the Zapfenmacher. One of the centres was Nuremberg. In the iamges of the Mendelsche and Landauersche Hausbücher of the Zwölfbrüderstiftungen it is interesting to note that the process step for the production of the taps shows only the reworking, but never the moulding. The illustration of the redsmith by Jost Amann in Hans Sachs book of trades gives at least a hint of the moulding material..

In the background, lumps of clay may have served as a raw material for the moulding material.

A little later again, in the 17th century, Christoph Weigel depicts the Zapfenmacher in its own right . Here a strong specialisation had taken place within a century.

The films are not about a strict archaeological experiment. Rather, it is a matter of examining some hypotheses on the manufacturing process. First and foremost, these were:

  1. Is it possible to make a wax model where plug and tap fit snugly?
  2. Can you cast this in such a way that there is little rework?
  3. How can the grinding of the plug into the tap be mastered manually?

Have fun watching. As always, I am looking forward to your criticism, questions or suggestions.

The first part deals with the history of the tap and the production of the wax model.

The second part is about moulding the wax model, pouring the tap and the first cleaning after casting.

The third part is about finishing the cast tap. This means that it must be roughed, filed, drilled and ground. The grinding of the plug into the tap’s body was particularly exciting. In fact, absolutely leak-proof tap can be produced with the simplest of means.

 

References


Aug 21 2014

Casting a medieval aquamanile

Bastian Asmus

Foundry: Medieval bronze casting of an aquamanile in a lost wax loam mould – by Dr. Bastian Asmus

The casting of an aquamanile in original medieval technique has been a long term intention of mine. A year ago I made an aquamanile in the form of a lion that dated to the medieval period, however I did not have time to cast that particular aquamanile in a technique that can be considered medieval.- The model however was made with the techniques known to medieval artificers.  It was made according to Theophilus Presbyter’s description in his schedula diversarum artium , a 12th century manuscript on artisan’s techniques. Theophilus’ chapter 61 on the making of the cast incense burners provides all the necessary information, with which an informed reader can go ahead an produce a formidable bronze (or any other copper alloy) casting. This information was used to prepare the mould for the casting of this aquamanile. There will be an article shortly on how to make the mould.

Reconstruction of a medieval loam mould for an aquamanaile in the form of a lion.

Loam mould of the lion aquamanile. The loam mould consists of the same ingredients as medieval moulds.

Casting a medieval aquamanile

The mould was prepared from  loam and made three days before the casting. The wax model was molten from the loam mould over embers. The mould was subsequently fired with charcoal. The charcoal was allowed to burn down to the top of the mould and before it was charged again with fresh charcoal. This was repeated three time s, just as Theophilus tells us . The casting was accomplished through the feet; so the mould is placed upside down for the casting. It was cast with a quaternary alloy of copper, zinc, tin and lead. The alloy is CuZn13Sn8Pb2 and was prepared for the casting.

References