While waiting for other substances to dry on the show wood, I dealt with colouring and protecting the cabinet’s exposed external pine surfaces with a minium wash.
It became common practice in the eighteenth-century to wash the back boards of case furniture with minium (red lead); its opacity disguised the (often second grade) pine boards and its toxicity was an effectual insecticide against attack by furniture beetles.
Lead, in its various forms, has been known to man for thousands of years and the Romans, who employed it in abundance, were all too aware of its toxic nature, naming it morbi metallici. The Romans also gave the name minium to lead tetroxide, after the area by the Miño River in northern Spain whence it was extracted from naturally occurring deposits (minium can also be produced artificially from a solution of lead nitrate and sodium hydroxide).
When new, minium is the brightest orange imaginable, however, after spending maybe, three hundred years on the back of a chest or cabinet, next to a damp wall, chemical reactions with the atmosphere, other compounds in the wash and chemicals within the wood itself, can render the original orange colour anywhere between salmon pink and chocolate brown.
I made up a pot of minium wash, comprising an extender, a binder and several edaphic pigments (to help simulate the natural oxidisation of an aged minium wash) and brushed it liberally over the external pine of the two cabinet tiers.