Sensitized Plywood Speeds Construction of Boeing Bombers

In its constant search for methods which r,vill put Boeing B-29 Superfortresses and other new models of airplanes into the air in the shortest possible time, Boeing Aircraft Company has put photographically sensitized plywood to work in its design and tooling program.

Both interior and exterior (waterproof) types of plywoods from one-eighth of an inch to two inches in thick- formation photographically reproduced on plywood at Boeing points the way for improved manufacture and tooling methods for fields other than aircraft construction.

Glenn H. Jones, photo template unit chief of Boeing Aircraft Co. at Seattle, Wash., has described the process as follows:

Liquid photo emulsion is applied to the surface of the t",;,ig lTi,I::iosrcrph ol c ness are used for wiring boards, templates, form blocks, instruction boards, display photographs and a multitude of other uses.

Douglas fir and maple plywoods are used most commonly and these are sensitized with a liquid-type photographic emulsion directly on either the unpainted or painted surfaces of the wood. A preliminary coat of white paint improves the contrast and makes reading easier.

Plywood templates particularly are advantageous to Boeing in the production of new experimental models as they give accurate information and quickly are converted into assembly jigs by attaching maple blocks and fixtures which are used to properly locate and hold the parts.

The increasing use of plywood photo templates and in- plywood by using a paint spray gun, the interior of which has been chrome or silver-plated to prevent contamination from the brass parts in the gun. Actual spraying is carried on in a standard spray booth which is lo'cated in a rubylighted room.

Much perlorqted this plywood table ig a iig or guidc lor drilling hotes in oirplcrne pdrtB dt c Boeing lircralt Conpcrny plcnt. The iig wcr urcde by photogrcphic reproduciion directly on the plywood ol the rnqtter drcwing cnd cuiling the designcted guide-holer.

Plywood templates are reproduced with a huge photo template camera by projecting glass plate negatives, previously made by photographing master layout drawings. The master layouts are hand-drawn on large lacquered steel sheets. When a draftsman has completed a layout it is photographed by the precision template camera at one-fifth the scale of the original drawing. A glass hegative is used so that there will be no shrinkage or distortion.

After exposure, the glass negative is processed, dried and placed back in the camera. A projection light is moved into place and the image is projected on a sensitized sheet of plyu'ood to the exact scale of the original drarving.

On plywood display photographs, rt'here scale and extreme accuracy are not important, regular film negatives are used. Negatives as small as 4x5 inches havc been enlarged to 5x1O foot plywood photos.