Basic Information about the Technology of Manufacturing Replicas

The starting point for making high-quality replicas of prehistoric pottery is the continual study of originals so as to obtain as much information as possible about their manufacture. Over the course of several thousand years, some objects lost a little of their original shape due to the gradual pressure of soil. The aggressive nature of surroundings has made it difficult to read their decor and a number of items broke into pieces as a result of insufficient firing.

These and many other problems had to be solved before we could start manufacturing ourselves. During the period of testing and experimentation, we had to determine the right procedure, suitable clays, natural dyes and the proper technique of firing. We found the theoretical information on manufacturing prehistoric pottery in most cases was unworkable and we had to solve many problems during the production process itself.

Clay
We supposed the originals were made from one type of clay. After many trials we finally located a suitable clay in the vicinity of Trenčín. This was from a clay deposit that had not been completely mined, two metres below the surface near disused brickworks.

Dyes
In order to achieve the colourful decor, we apply natural dyes which were also used by the original manufacturers. Black is produced by graphite, red by haematite and for white colouring we use white clay or limestone paste.

Coating – polished decor
Pottery without a coloured decor is polished once. However, pottery with a coloured decor, typical say of Dunajská Lužná, must be polished twice. The first polishing removes all the uneven details, as all traces of modelling are smoothed and the base is prepared for coating. It is the paint itself which undergoes polishing the second time around. With each item it is very important to estimate the right moment for polishing. The pottery must be sufficiently damp. Larger items are polished gradually while they’re drying out. The polishing technique is also crucial for the final appearance. We use stones and bones for polishing. Engraved decorations are made with tailored bones.

Decorations using impressions are made in a variety of ways depending on the original techniques applied by manufacturers over historically different periods. They used various types of materials – string, twig imprints...

Firing  the Pottery

Kiln
We built a replica of a Celtic kiln in order to fire our prehistoric pottery. We only used this kiln for two years as it was too big and required excessive physical strain to be operated by just two people. In it however, we were able to fire pottery at 900° C and we could reach temperatures of up to 1200° C.

before firing

after reduction  firing at 1200° C
the grate began to melt and liquefy

The procedure for firing in a field kiln.
The pottery is carefully dried and then placed into the kiln with the openings turned away from the flames. Depending on the size of the kiln and the pottery, a small fire is maintained for 5 to 7 hours. It is necessary to maintain the fire for this time to ensure a uniform temperature throughout the kiln. The heat is then gradually raised to the required temperature. Depending on the size and type of kiln it takes approximately 10 to 15 hours. The final temperature within the kiln is maintained for about an hour. It is important during the whole firing process to pay attention to any temperature fluctuations. Incorrect stoking of the fire can raise or lower the temperature by as much as 200° C within just 2 to 3 minutes. The fuel we use is a combination of beech and spruce timbers.

Prehistoric pottery is fired in an oxidizing as well as a reducing flame. During the oxidation process the pottery turns terracotta in colour. Towards the final stages of firing, the reduction process generates colours ranging from light brown to black depending on intensity. Higher temperatures may even result in a metallic sheen. Pine wood and fresh pine branches with needles are used for the reducing flame.

We try to identify the methods originally used in shaping each item and use these in the manufacture of our replicas. We know of three basic methods of manufacture. All pottery was shaped by hand as the potter’s wheel had not yet been developed.

Small items were shaped gradually from one piece of clay. A typical example of this practice is the pottery of the Bukovohorsky culture [Domica Cave]. We have discovered two techniques for modelling larger items. The base was made first and then they laid clay strips 3-5cm wide and 1-2 cm thick. They continued linking these until the vessel was completed. This method can be used only with pottery of simple forms.

Roll technology was used more often. Clay rolls were made with a diameter of 2-3 cm and then laid as described above. This allowed atypical shapes to be made as the weight of the newly added clay was not that heavy as to deform the vessel. Depending on the shape and size of the vessel, practical experience has shown it is necessary to suspend the laying of strips of clay and allow them to partially dry out before adding further layers. This method was used in the production of pottery found in Dunajská Lužná.

After reduction firing

800°C

Peter & Pavol Vozárik
Vojtecha Zamarovského 59/1
Trenčín,  911 01   Slovakia

Tel.: +421 902 322 927
Email: peter.vozarik@gmail.com