unknown cast aluminum to 6061 plate

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Hello all,I want to weld a 1/2" piece of 6061 to an unknown alloy cast piece. the cast piece is probably less than 1/4" thick,but until I cut the old flange off I won't know for sure.My question is this something that can be accomplished with a TIG machine that has a max output of 175 amps, and if so what would be the best way to do it? It is an adapter for a 90mm throttle body on a Ford 5.4 intake manifold. Thanks, Jim
Reply:175 is cutting it close for amps, could always preheat it a bit before welding. and use 5356 fillerR.T. Welding LLCOn Site ServiceColumbus, NJ
Reply:either preheat or a helium/argon mixture of shielding gasMillermatic 211Miller Syncrowave 350lx with cooler and tigrunner Thermal Dynamics cutmaster 811955 National Cylinder Gas O/A setup with original patina
Reply:Thanks guys, definitely will preheat,wasn't sure of the proper filler to use,don't really want to buy a bottle of helium and my Precision Tig 175 will have to suffice.My main concern is weldability of dissimilar alloys,not knowing enough to even be dangerous ... What electrode do you recommend ? Thanks again. Jim
Reply:Originally Posted by jmm03Hello all,I want to weld a 1/2" piece of 6061 to an unknown alloy cast piece. the cast piece is probably less than 1/4" thick,but until I cut the old flange off I won't know for sure.My question is this something that can be accomplished with a TIG machine that has a max output of 175 amps, and if so what would be the best way to do it? It is an adapter for a 90mm throttle body on a Ford 5.4 intake manifold. Thanks, Jim
Reply:the 5356 will take care of thatR.T. Welding LLCOn Site ServiceColumbus, NJ
Reply:I just welded an intake for a race car yesterday. It was a rotary Mazda.  The manifold had been modified by the engine builder and we didnt know how well the cast aluminumwould weld until I started.  I weld cast a lot and find that 4043 is my go to filler for cast......Not saying 5356 wont work but have had good results with 4043......I actually used 4943 and was pretty happy with the way things turned out....As a normal practice I like to skim off the casting with an  angle head sander and 80 grit  and a wipe with alcohol if you like.....  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Hi BC, after researching a bit I was going to ask about 4043. I don't know if manifolds get above 150 F.,but that seems to be the upper temp level for 5356.(at least recommended...) What iv'e read also is that 4043 melts lower so paying attention to get good penetration is more important.I assume that preheating is recommended on it also,is that correct?Appreciate everyones help. Jim
Reply:4043 will flow better.    5356 may crack from continued heating and cooling.IF you clean off the "bark" from the cast do not use wheel or paper made of aluminum oxide.   It will make it harder to weld.Make one pass with the tig torch and no filler to float out the crap.  Clean it up and weld.I have a PT225.   with preheat your machine is plenty big.   Clean, Clean Clean.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David R....David.....
Reply:If your intake manifold gets hot enough to melt the weld you have a lot more to worry about than the filler material...... As mentioned before, 4043 is pretty much my GO TO filler for cast....The 4943 works good also and has more tensile strength.... Last edited by B_C; 01-18-2014 at 08:14 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock