Tham khảo tài liệu 'navfac p-433 welding materials handbook_10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http Smooth finishes can be obtained by placing a sheet of polyethylene or waxed paper over soft deposits. Remove when hardened. Trowels or spreading tools can be moistened with water between strokes for smoother deposits when applying. Use M-50 Nobond Wax on surfaces not to be bonded. For detailed reproductions from molds and patterns apply Nobond in several coats. Allow each coat to dry then buff before applying additional coats. Brush a thin coat of compound on mold surfaces before casting the remainder of the mix. Use reinforcing screens and tapes to minimize warpage and to increase overall strength. When casting large deep shapes pour compounds in several steps allowing prior deposits to semiharden and cool before adding additional compound. 3-17 Simpo PDF Merge and Split UnregisteredcVersion - http INTRODUCTION Methylacetylene propadiene MAPP gas is a versatile multi-purpose industrial fuel gas that offers excellent performance safety and economy. It is used to flame cut flame weld braze solder pre-heat and for stress relief. The only equipment usually required to convert from acetylene to MAPP gas are new torch tips. One cylinder of MAPP gas will do the work of five acetylene cylinders. MAPP GAS IS SAFE At 70 F MAPP gas can be used safely at full cylinder pressures of 94 psig pounds-per square inch gauge . Acetylene is limited to 15 psig. MAPP gas toxicity is rated very slight but high concentrations 500 ppm can have an anesthetic effect. Local eye or skin contact with MAPP gas vapor has caused no adverse response but the liquified fuel may cause frost-like burns. MAPP gas is chemically inert to most common materials including steel brass most plastic and rubber. There is a slight possibility MAPP gas may react with copper or alloys of more than 67 percent copper to produce explosive acetylides when the gas is under high pressure. To be on the safe side use steel or aluminum .
