Since working on antique furniture, my approach to adhesion of veneers and marquetry work has changed, and I would add, changed for the better. I no longer use modern glues such as PVA, or the dreaded contact adhesive. Instead I only use reversible glues. These essentially are protein glues (also called Hide Glue) which can be applied hot. Hot protein glues go back hundreds of years and are still used today when working on restoration of antique marquetry and cabinet work. This is an essential requirement since the glue can be reversed at any time regardless of how long the glue has been present, even hundreds of years. Application of heat and water easily softens the glue allowing marquetry, and joints in cabinet work to be released and re-glued. This can be repeated time and again without any effect on the stability of the bond. It is the reversibility of the glue that attracts me, but the down side is the skill and equipment required to perform the technique. While not a problem to me, I understand those who are reluctant to purchase a gluepot and learn the technique.
The good news is a relatively new, modified protein glue, is now commercially available, and can be used straight from the bottle.
‘Titebond’ sell Hide glue in a plastic bottle, which has the additive of Urea. This changes the chemical composition, making the glue jell for as long as it is confined to the bottle. To make the jelled glue runny, simply submerge the bottle into hot tap water for about half an hour and it liquifies the glue allowing it to be squeezed out and spread across a surface as you would with PVA. The open time is about 15 minutes and after application, sets in one hour. I still leave it in the press overnight, a habit I cannot get out of. For marqueteur’s, this is a major advantage since it allows changes to marquetry to be carried out anytime during completion of the work. Simply heat and wet a part of an unwanted marquetry piece and cut and glue in a change. We have all had that situation where one aspect of the marquetry looks wrong, perhaps when the first coat of polish is applied. If using PVA one is reluctant to gouge out pieces because of the permanency of the glue. Now that scenario comes to an end. Follow my lead and enjoy Urea-Hide glue, you will not regret it. In the USA it goes under the name of ‘The Old Brown Glue’ developed by furniture maker and marqueteur Patrick Edwards, but across Europe ‘Titebond’ sell it as “Hide Glue” as seen illustrated. Both products provide the same excellent results.
This glue differs from hide glue, in as much as instead of being made from the skins and bones of animals, fish glue was originally, in the 18th century, made from the swim bladder of the sturgeon. Today, fish glue is made from the swim bladders of cod and sold in the USA. Not easy to obtain in the UK, but through a Canadian friend I am able to purchase it. Like hide glue it is fully reversible, but unlike hide glue the open time is increased to 1.5 hours, but requires pressing for 12 hours. It has excellent gap filling properties. Lee Valley Tools in Canada and America sell the glue.