tension spring 66 when the rack 46 and its cargo of substrate 32 impact the anvil 68 the excess solder is freed from the substrate surfaces as well as from the rack surfaces and discharged back into the vessel 62 since the operation takes place immediately above that vessel however not all of the solder is freed from the substrate and rack surfaces in one operation because of the tendency of solder which has been freed to be recaptured in another place the operation of the machine 50 then is such that the rack is subsequently recocked then released several times in rapid succession such that typically four to eight impacts are accomplished in approximately one and one half seconds since the excess solder is propelled in the direction of the vessel 62 no special catching mechanism is required and the solder thus ejected is immediately reusable after the last impact of the rack 46 against the anvil 68 the anvil is retracted fig1 the rack pivoted to its traveling attitude and the arm 48 is advanced by the conveyor 52 to a quench station occupied by another flux receptacle 60 the rack 46 is caused to descend into a flux and solvent mixture within the receptacle 60 for cooling and cleaning the residual flux from the substrates 32 this particular operation and subsequent cleaning and pin tinning operations performed by the machine 50 are substantially the same as performed by the unmodified austin tinner machine the specific structure of the modified mechanisms of the machine 50 which comprise the invention will now be described with the arm 48 positioned so as to.