Scientists in Estonia, using infrared spectroscopy, have been able to identify the adhesive used to glue an early Mesolithic microlith to its wooden shaft as birch bark tar. Their sample came from an excavation at Pulli and was found together with a lump of the same adhesive with teeth marks where it had been chewed. Read details here http://www.primitiveways.com/birch_bark_tar.html
Birch bark tar has long been known as the ‘superglue’ of the stone age. It has been found on a Neanderthal spear point, with a thumb print. Pieces of chewed
birch bark tar with human teeth marks go back as far as 11,000 years. Otzi’s
5,300 year old copper axe was hafted with birch bark tar.
Mike Richardson, who lives in Anchorage, Alaska, has experimented with making his own birch bark tar. Mike says, ‘Birch bark tar is a thermal plastic material, that is a solid at 65 degrees Fahrenheit. At 85 degrees Fahrenheit, it is just a bit softer and can be molded in your hands. At 105 degrees Fahrenheit, it is a medium stiff putty. At 135 degrees Fahrenheit, birch bark tar is a softer sticky putty. Birch bark tar boils at about 352 degrees Fahrenheit.”Birch bark tar is not made from the sap of birch trees like birch syrup. It is made from just birch bark heated in a oven with little air, much like charcoal. The birch bark oil, mostly betulum, will sweat out of the bark and run to the bottom of your oven.’
Read Mike’s article in full: http://www.primitiveways.com/birch_bark_tar.html
Visit The Museum of The Stone Age: http://www.stoneagetools.co.uk