A masking tape or sheet comprising a substrate comprising a resin (a) comprising a polypropylene as a hard segment and an olefin copolymer as a soft segment, and an adhesive layer formed on one side of said substrate. The masking tape of the present invention can precisely follow the shape of adhesion surfaces having curves, and can provide fine parting lines. In particular, when polypropylene resin (b) is added to the resin (a), the back face of the masking tape becomes smooth and can be adhered easily with fingers, and the tape can be easily cut with a cutter knife. Hence, the use of the masking tape of the present invention leads to an improved efficiency of adhesion work, particularly when the work is manually done. In addition, since the masking tape of the present invention does not contain vinyl chloride in the substrate, the masking tape after use can be incinerated without generating a toxic gas such as chlorine gas.

A method of controlling bulk absorption of atomic hydrogen and facilitating degassing of hydrogen from aluminum alloy workpieces during heat treatments in furnaces with ambient and/or moisture-laden atmospheres to prepare for fabrication in sequential working stages, the method includes exposing the surface of the workpieces to an etching process after each or any of the sequential working stages, and subjecting the workpieces to a final etch treatment using an inorganic alkaline or acidic etch solution modified by an addition of five to twenty-five weight percent transition metal chloride salt before being subjected to said heat treatment. The workpieces exposed to the transition metal chloride salt modified etch solution are subjected to the heat treatment. The etch solution is used to substantially decrease the amount of atomic hydrogen entering the bulk of the workpieces and to facilitate removal of atomic and molecular hydrogen from the bulk of the workpieces during the heat treatment.

The laminate of the invention is provided with an etch stop to protect the laminate's adhesive layer. The etch stop also circumvents any etching interference due to degradation products which would arise from breakdown of the adhesive layer. The etch stop is a protective thin film in the form of a metal oxide, metal nitride, metal oxynitride, metal carbide or metal oxycarbide coating deposited on the back side of the metal sheet prior to lamination onto the substrate by means of an organic adhesive. The thin etch stop film is in the form of a blanket coating to assure adhesion to the metal surface and to the adhesive. It may be deposited onto the metal sheet by standard vacuum deposition techniques such as DC and magnetron sputtering, thermal and E-beam evaporation, chemical vapor deposition, and plasma enhanced chemical vapor deposition methods. The thin film thickness is flexible, and can range in thickness from tenths of angstroms to microns.