For Milliput Putty, check "That" Auction Site -Sellers (both in the UK and the US) offer it in 3 grades: Fine, Medium and Coarse. Also a Terra-Cotta Coloured Version. (I prefer "Medium" myself.)

Also, Canadian Tire is supposed to have a Blue/yellow 2-part epoxy putty called "Need-A-Tite" (or "Knead-A-Tite"?) Apparently similar to Milliput but I've never used it.