This is posted on behalf of Ewa Bjordell, an intern at the Canadian
Conservation Institute:
  We are looking for a supplier that can deliver a clay similar in
composition to  english ballclay that was used for tobacco  pipe
manufacture in the first half of the 19th century.  According to Iain
Walker ( 1977), the most common clay used for making pipes in Britain
during this period was Devon ballclay.  English ballclays have a low amount
of iron (1%) but are (according to some sources), high in carbonaceous
matter.  The amount of SiO2 is between 47.51 - 54.89% and the amount of
Al2O3 is between 30.90 - 34.14%.
  The clay will be used to make grounds for canvas in order to prepare the
canvas for painting.  Since we would like to start making up the grounds
before the end of January, we need to find a supplier that can deliver the
clay promptly.  With thanks in advance for any suggestions.
 
Judy Logan
Senior Conservator
Canadian Conservation Institute
1030 Innes Road
Ottawa ON
K1A 0M5
 
tel: 613 998-3721    fax: 613 998-4721   e-mail: [log in to unmask]