This invention provides a method of sealing and purging contaminants from the internal free spaces of an insulated electrical device by forcing into said free spaces a low viscosity material that acts to displace fluid contaminants from within said free spaces. The material later cures in situ to form...http://www.google.com.au/patents/US4171998?utm_source=gb-gplus-sharePatent US4171998 - Method for decontaminating and sealing the interior spaces of an insulated electrical device utilizing mineral oil-extended polyurethanes
