Shellac[]
Formula: Mixture of compounds of average elemental composition C16H26O4[]
Description: Shellac has been in use as a binder and fuel for many centuries, but has been gradually replaced by Red gum . However, it is still sometimes claimed that shellac is a superior fuel for use in coloured compositions. It is a somewhat brittle but strong resin that dissolves in ethanol and acetone, albeit slowly.
Hazards: Shellac is not particularly dangerous or toxic. However it may be dissolved in methanol which is poisonous.
Sources: Shellac is available from artistic painting or woodworking supply stores. They usually have several varieties, of which 'orange shellac' works well. Some hardware stores also carry it under the name "white shellac".