Abstract: Residual formaldehyde contained in urea formaldehyde structures is immobilized by subjecting the structure to a gaseous mixture of a carrier/penetrating gas and a reactive gas chosen from the group consisting of anhydrous ammonia, ozone and mixtures thereof for a period sufficient to react with and immobilize the formaldehyde. In building construction utilizing urea formaldehyde foamed in place insulation the method comprises the steps of injecting the gaseous mixture of the carrier/penetrating gas with anhydrous ammonia, ozone or a mixture of anhydrous ammonia and ozone into the stud space containing the foamed in place urea formaldehyde insulation. For structures in which particle board or similar manufactured sheet material contains residual formaldehyde the formaldehyde may be reacted by exposure of the surface of the panel to anhydrous ammonia, ozone or mixtures thereof contained in the carrier/penetrating gas.

Abstract: An apparatus for lapping the edges of a metal foil tape to remove burrs. A pair of coaxial counter-rotating wheels have facing annular abrasive surfaces which are spaced apart a distance less than the width of the tape. The tape is drawn between the wheels, generally along the wheel diameters, with the tape edges in engagement with the abrasive surfaces. The peripheral velocity of the wheels is substantially greater than the lineal speed of the tape so that the tape edges are polished substantially at right angles to the plane of the tape.