Abstract: The present invention relates to wall structure and components thereof and manufacturing methods therefor and, more particularly, in view of present energy crisis considerations, to a structural assembly comprising a plurality of individual components interconnected to form an integrated unitary structure of desired configuration such as but not limited to parabolic and/or other curved surfaces forming troughs, saucers, domes, flat wall structures and/or combinations thereof, some of which have particular utility in connection with reception and collection of various kinds of radiant energy including solar energy, without requiring or utilizing a pre-erected frame structure.

Abstract: Butt welding of workpieces of similar or dissimilar materials, such as aluminum to aluminum and/or aluminum to steel, having similar or dissimilar cross sections is accomplished by a frictional welding process wherein the average relative speed of the faying surfaces is between about 4 and about 25 feet per second, the pressure urging the faying surfaces into mutual engagement is between about 7500 and about 15,000 pounds per square inch while energy is supplied to the weld area in the range between about 4000 and about 17,000 foot pounds per square inch of weld area, and the formation of the weld is achieved within about 650 milliseconds.

Abstract: The present invention relates to the making of an evaporator or condenser construction wherein ends of heat exchange tubes extending through heat exchange plates or fins are joined with return bend connectors. The ends of the tubes are provided with flared cups that telescopically receive the ends of return bend connectors. Nibs are formed on the outer surface of and extend outwardly a predetermined amount from the outer surface of the return bend connectors near the ends thereof. Grooves are formed on said outer surface and extend longitudinally between each nib and the end of the connector. When the end of a return bend connector is inserted into a flared cup, an interference fit between the nibs and the cup centers the end of the connector in the cup and frictionally retains the tube and the return bend in assembled relation when the assembly is inverted and thereafter submerged in a solder bath. The grooves provide vents for hot gases during the soldering operation.