Hello Jim. from what I have gathered from online sources is that dip molds probably were not made of wood, but of ceramic/clay and some were made of brass or copper. I believe that dip molds of wood were not to feasible because of the extreme hotness of the glass being held by the mold, whereas in a two piece mold the release of the bottle would be a lot faster. But case gin bottles which were tapered were formed with wooden paddles passed up and down over the parison of glass as it cooled on a marver table, at least this was the description given on one source. Some case gins have sides with vertical lines or ridges which came from the iron and brass dip molds, but they are late in the mnfg process, the wooden paddles were used in the 16th 17th centuries, and the brass iron molds were into the 18th to 19th centuries, from what I have researched, fascinating hobby bottles are!!!......AndyBut the example given by RJ2 is a two piece mold. the dip mold is one piece, with the base being smaller than
the top so the blown glass can be removed. the history of early glass making is a fascinating discussion
Thanks everyone for their input.