Wood and Leather
Various items of wood recovered in 1993 required more elaborate conservation techniques than were available at the Pensacola Shipwreck Survey headquarters (Mitchell 1993). These included two dunnage specimens, two tool handles, a galleon carving, a cork, and small timber recovered from the port pump well. Each of these specimens was treated by freeze-drying at the South Florida Conservation Center in Pompano Beach, Florida. Prior to freeze-drying each artifact was given a pre-treatment in PEG (polyethylene glycol, 30% PEG 300, 20% PEG 1000, and 10% PEG 400 in distilled water) for six weeks (Maseman 1994).
Similarly, all leather artifacts were treated by freeze-drying following a pre-treatment in 15% glycerol for four months (Maseman 1994). Both the PEG and glycerol pre-treatments were designed to “bulk” up the wood and leather prior to freeze drying. The methods successfully prevented subsequent cellular collapse (that could have led to extreme shrinkage and deformation).