Stabilized methylacetylene propadiene (MPS) as an alternative to acetylene for welding instruction

Abstract

The purpose of this study was to determine the feasibility of using stabilized methylacetylene propadiene (MPS) fuels as an alternative to or supplement for acetylene in oxy-fuel welding education. MAPP (a trade mark of AIRCO, Incorporated) was used as the representative of the MPS fuels because of the favorable chemical composition and ready availability. The flame characteristics, flame chemistry and effects of the oxy-MPS process for welding were reviewed. This experimental study used two groups of students, each trained with one oxy-fuel process and then switched to a second process. The study described the statistical analyses and mechanical testing techniques used to measure the effectiveness of different filler metals and oxy-fuel procedures. Data were collected from sample welds made on 1/8th inch, mild steel coupons. The greatest difficulty encountered was with flame adjustment. The study concluded that MAPP gas, and potentially all MPS fuels, can be used to make sound welds in mild steel and can play a part in welding education. The fuels are limited by the difficulty with flame adjustment. This study established the feasibility of oxy-MAPP welding using the deoxidizing filler metals developed for the gas metal arc welding process. It demonstrated a difference in teaching effectiveness between oxy-acetylene and oxy-MAPP systems for prospective technical educators. The skills learned with the oxy-MAPP process transfer more readily to oxy-acetylene welding than skills learned with oxy-acetylene transfer to oxy-MAPP. The study reviewed a possible innovation in oxy-fuel torch tip design (a counterbore) as well as the relative safety in oxy-MPS systems. Recommendations for the utilization of oxy-MPS: (1) Oxy-MPS systems can be utilized as comparative fuel systems with oxy-acetylene, giving students a chance to compare fuels. (2) Oxy-MPS can be utilized where familiarization with oxy-fuel welding is the primary goal and weld quality is secondary. (3) Oxy-MPS can be utilized for any oxy-fuel heating application in which weld quality is not critical. (4) Further study should be done to establish a practical flame adjustment technique for oxy-MPS welding.