PVA stands for 'polyvinyl acetate adhesive' this universal wood glue first became available during the late nineteen sixties,it was a complete change from the inconvenient rabbit glues available in granule form it replaced that needed heating over a flame,the PVA revolution was slow at first to take off but gradually craftsmen and model builders began to appreciate the advantages of this material.Gone were the glue warmers and out came the convenient plastic bottles of what looked like thick white milk,many were staggered at how neat joints could be made and especially how it dried to a clear finish,people began to experiment and find other uses for PVA which were far and beyond the normal intended use of sticking wood together. Builders needed something to seal concrete floors,and one day by accident a chippie knocked over a bottle of the adhesive onto concrete,he left the adhesive as he went for his teabreak only to find that when he returned to clean up the mess it had formed into a glazed shell on the surface of the floor,thus by an happy accident the adhesive was discovered as making a first class sealer and is now sold in large tins for that very purpose. Schools were quick to buy in the adhesive as a first class substitute for messy,flour and water paste for making up papier mache models,once more the models dried rigid and did not fall apart especially once chicken wire and other supports were added to the structure,the PVA adhesive name had spread far and wide and rabbit glue was a thing of the past. One of the excellent qualities is that it can be thinned as desired for different applicatiuns,from priming wood and card to using as a substitute for model aeroplane dope to tighten up covering material,in fact in a few years time dope will vanish from the shelves and be replaced by materials like this,already the old plastic wood products that once contained cellulose now have PVA as their base material,odourless and clean to use. There are times when PVA is unsuitable such as when in contact with metal,it will quickly corrode metal structures unless a membrane barrier of say clear varnish is added before the joint makes contact. In recent years a variation of PVA has been deleloped that uses resin,this is called Aliphaetic resin adhesive which uses the early principles of PVA beads but with waterproof crisper setting to aid sanding and be more waterproof something that PVA is not.Aliphaetic resin is more expensive but also has increased drying rate due to the way it is made during manufacture,it also has excellent quick grab qualities. One tip when glueing together sheets of balsa to make laminated sections,is to first apply the PVA and then with a piece of glasspaper rubbed together sprinkle some of the glass debris onto the adhesive,clamp together the wood by the use of weights or clamps,and the wood will not slide as the tiny beads of glass embed themselves into the woods surface. The versatile nature of PVA has ensured a long and popular life with craftsmen today who continue to find more uses for this product.