Faster Setting Of Glue Under Heating Process

Press, Volume XC, Issue 27400, 13 July 1954, Page 12

Faster Setting Of Glue Under Heating Process

Setting of glue in furniture manufacture in 10 minutes compared with four hours under normal conditions has be'fen achieved by electrical heating processes developed by the Canterbury College Industrial Development Department. Two manufacturers in Christchurch have found that this reduction in time, besides saving labour, releases jigs and presses for continuous operation, so that there are all-over economies and increased efficiency. Before the Second World War, the only heating methods used in this type of work involved the use of very expensive steam-heated platens. The construction of several series of wooden aircraft during the war focussed attention on the need to improve this cumbersome and timeconsuming operation. A more versatile and flexible means of applying heat under control was sought. A British scientist conceived the idea of passing a heavy electric current through a sheet of metal to raise its temperature and then applying this conductor to the wooden components to be glued together. Eventually an extension of this principle was used in the construction of the Mosquito aircraft. The Canterbury College Industrial Development Department was conversant with the principle and in the last two years has developed it to suit local conditions and demands with the co-operation of two prominent furniture manufacturers. To fabricate veneered bed-ends, cup-

board doors, and other sections, the individual layers of timber are coated with glue by machine and then assembled in a flat press with a sheet of stainless steel between each unit assembly. The press is then closed down to bring all surfaces into close contact. Electricity from a low-voltage heavy current transformer is then passed through the steel sheets, sufficient to set the glue in 10 minutes and release the press for a fresh batch of components. The synthetic glue, when thus raised to 160 degrees Fahreinheit, sets in a fraction of the four hours required at room temperature. For curved sections, the steel sheets are arranged on curved formers which fit into a vacuum press. This type of press relies on the pressure of atmospheric air to force the wooden parts of the assembly down into the curved formers. Heat is applied as before for gluing. Using this technique, curved doors and cabinet tops can be glued in half an hour, compared with four hours in summer and eight hours in winter when ho heat is used. It has taken two years’ work by Mr N. B. Manssen, senior engineer of the Industrial Development Department, and the co-operating manufacturers to perfect this new technique. The furniture trade is gratified with the achievement. It has been found that once manufacturers become familiar with the general principles they have been able to adapt their own methods of using this low-voltage strip heating, thus further expanding the versatility of the technique.