CORROSION COMMENTARY Available to Purchase

NEW KINDS OF CORROSION. That one door opens and another closes might be looked upon as a ‘law’ of scientific progress. The development of synthetic glues for plywood and other bonded woodwork was a notable stride forward for strength and for reducing the risk of woodworm or beetle infestation. Now, as the latest D.S.I.R. Annual Report (1955–56, H.M.S.O., 1957, p. 29) reveals, vapours from these synthetic glues can cause serious corrosion with metals. Both phenol and formaldehyde vapours have corrosive effects, and these substances are major components of many of the new synthetic glues and adhesives. At relative humidity of 90 per cent. and in the 25 to 30°C. temperature range, formaldehyde vapour is very corrosive to the common constructional or plating metals, e.g., brass, copper, cadmium, zinc, mild steel, lead and solder. Phenol is less aggressive; although its vapour may stain some metals, it attacks only cadmium with severity. However, these vapours are given off quite slowly from wooden packaging units or from modern cabinet work containing metallic parts (e.g., a radio set), and the risk of corrosion is sizeable only in enclosed space conditions such as during storage or long transport. With normal access to air, the vapours would not accumulate to present any significant threat.