1. The document describes experiments conducted to test potential glue types that could have been used in the Stone Age, including birch bark tar, pine tar, pine resin and bee wax mixtures, hide glue, and blue bell glue. 2. Two methods for producing birch bark tar are described - an open distillation method using a clay pot over an open fire, and a closed distillation method using covered pits. Both methods were found to work well but consumed large amounts of firewood. 3. Additional experiments tested producing pine tar through open distillation and compared it to birch bark tar, as well as mixing pine resin, bee wax, and charcoal which was found to produce a very hard and strong

1. Experiments on possible
Stone Age glue types
Werner Pfeifer
Werner Pfeifer, Marco Claußen
Steinzeitpark Dithmarschen
Albersdorf, Germany

2. Glue types produced:
1. Birch bark tar / pitch
2. Pine wood tar / pitch
3. Pine resin / bee wax glue
4. Pine resin / bee wax / charcoal glue
5. Hide glue
6. Blue Bell glue

3. Tar and pitch
is a product of distillation of for example birch bark or pine wood.
Tar is a fluid, watery form, pitch a more solid form of a complex chemical
composition, not better defined in my sources.
Tar was mainly used to seal and conserve wood and leather, but also used in
medicine, mainly as desinfectant. In North- and East European countries also
ingredience of food and cosmetica.
Pitch was mainly used as a glue e.g. in archery and to fill small openings e.g.
in ship building.

4. „Open and closed distillation“ methods used

5. „Open distillation“ method:
Observations:
1. „smoke“ within 10 minutes
2. first liquid dripping within first 20 minutes
3. after firing 2h, bark had turned into charcoal
4. consumption of a wheel barrow load of wood for each experiment
5. isolation layer sealed very good, except one experiment with higher fine
clay content
6. raw clay pot turned into fine ceramic, black colour inside indicating
burning without oxygen

6. Preparing the pipe

7. Stone support ring
Birch bark pile
Isolation layer

8. Isolation layer
sealed

9. Covered in
dry grass

10. Immediately fired
for minimum of
2 hours

11. „smoke“ while firing

12. gaining liquid and tar

13. after cooling down
sealing layer still intact

14. charcoal from
birch bark
profile of
sealing layer

15. Conclusions:
1. method works well
2. pitch yield was very low due to low quality of birch bark
3. sealing layer consist of high persentage mud and sand,
but just little clay works very well, too much clay results in cracks
4. Sealing layer burns into soft, brittle sherds, dissolves quickly,
no traces for archaeologists after several years
5. No visible traces of tar in „sand only“ experiment.
6. Consumption of large amount of wood suggest prehistoric distilleries to be
in former woods, not in settlements.
7. Clay pot turned black inside without visible traces of tar.
Thus look for these sherds and do chemical and microscopic investigations
inside the sherds when searching for Stone Age tar distillation indications.

16. „Closed distillation“ method
by Marco Claußen
Observations:
1. Although most heat of the fire is going upwards, most birch bark in the pits
turned into charcoal, specially in the upper parts.
2. The yield of liquid and tar seemed to be slightly more than in the „open distilling“
method.
3. It needed about the same amount of fire wood as above experiments.
4. One experiment with a 60cm deep pit failed to produce enough heat,
due to reduced oxygen in the pit.
5. One experiment with building a heap over a pile of bark failed, due too thick
isolation layer (8 – 10cm).

17. The pit
The skull vessel
The clay bottom

18. Pilar stones

19. Deck stone
above vessel

20. Marco and his
pit

21. Birch bark added

22. Filling gaps with
grass and twigs

23. Covering all
with grass

24. A layer of soil
on top

25. Firing for
2 – 3 hours

26. Let it cool down for
minimum one hour

27. Opening it
carefully
Grass turned to
coal
It's still hot, see
smoke

28. Most birch bark
turned to coal, lower
parts not

29. After removing
deck stone:
Tar inside skull,
plus outside, due
to skew placement
of skull
Tar in clay pit did
not enter the clay
and was scooped
out later

30. Conclusions:
1. This method works very well.
2. As wood consumption is very high, I expect the Stone Age distilleries to be in
former woods, not in settlement.
3. As the fire needs a lot of oxygen to reach high temperatures, deep pits are
no good. Fires on or above ground level work well.
4. The isolation layer between fire and birch bark must be thin. More than 4 cm of
soil seems to be too thick for the heat to enter the inner properly.
5. The remains of this distillation process leaves no long term visible traces other
than of a „normal“ camp fire.

31. Turning tar to pitch
Heating it carefully
Skull works very well
Future heating
experiments planned
with
birch bark container,
hooves and horn,
and wooden bowls

32. Pine wood tar and pitch
Aim: producing pine pitch to compare it with birch bark pitch
1. „open distillation“ method (with metal container)
2. finger thick pine wood was used
3. wood turned into charcoal, used later for heating tar to pitch
4. pine pitch looks alike birch bark pitch, smells different
5. future experiments need to compare glueing abilities

33. Pine tar and liquid
after distillation

34. Pine wood distillation
after firing for 2 hours

35. Pine resin /bee wax
glue
on arrow heads

36. Pine resin / bee wax / charcoal glue
Mixing above components 3:1:1 gives a very hard and strong glue
I got the recipy from Ben McNut (Woodsmoke bushcraft company, UK) and had
tested it several years ago on arrow heads. It's a very good glue.
As it is black in colour, it might easily be mistaken for birch bark pitch
in archaeological contexts, just by the look at it.
As it is very easy to make, much more easy than distilling tar / pitch, I could
imagine, that it had been used in Stone Age very well.

37. Hide glue
Hide glue and bone glue was used until very recently a lot in binding wood, horn and
hide onto each other. Friends of mine use it in making traditional Asian composit bows
or glueing reptile or fish hides on the back of a bow.
I made two experiments by boiling hides in water:
1. Pig hide is too fatty and did not melt.
2. Cow hide turned into good glue.
As hide or bone glue is effected negatively by moist weather, if not sealed, it might
have not been used in Western Europe during Stone Age, but in dryer areas it might
have, as it is made easily and the raw material was always available.

38. Cow hide glue
(left)
Pig hide too fatty to melt
(right)

39. Hyacinthoides non scripta
Blue Bell

40. Hyacinthoides non scripta Blue Bell

41. Onion of the
Blue Bell
when squeezed