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Welding alum manifolds and heads

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  • Welding alum manifolds and heads

    OK, so most cylinder heads are 355 t6. If you weld them with 4043 it machines like crap. And is soft. Some guys use 5356. It machines well I am told.
    One other guy said he welded alum without using ac and did not use either of these rods. He did a bunch of stuff for BAE, so must have come up with something.
    I also do some welding on 6061 T6. Same thing. I want good machineability. Suggestions?

  • #2
    I have the same problem . . . Tapmatic #2 for Aluminum helps a lot with the machining. I've not used 5356 because it's not recommended for service above 150 degrees.

    4047 filler welds well, is slightly stronger than 4043 as welded, and machines a little better. I've ordered a sample of A355 filler (also referred to as 4009), but don't have it yet. 'Don't know how it will machine or what it will cost.
    Dynasty 300DX
    Hobart Handler 120
    Smith LW7, MW1, AW1
    Smith AR/He Mixer


    • #3
      I would use the 5356. My Edelbrock lower intake had a casting crater in it. I used the 5356 to fill it up and grind it smooth. Works well. Good luck.


      • #4
        He would only say he used a lot of helium. He said about 50% mix. This made a bunch of heat. He had to mix bottles himself.
        Without the AC he was losing cleaning abilty? He would not give the rod he used, though.
        Filling a crater can be done with anything. ****, JB weld will do it. It is a far cry from welding chambers, o-ring groves, seat areas, etc. then planning on having it last without heat treating again, hold threads, seats, etc.


        • #5
          Yes would lose all cleaning principle of positive side of ac, would be all penatration, You can weld aluminum on dc straight with 100% helium, 50/50 mix does not work in my experience on dc- it would always turn black unless used 100% helium, so not sure on that, But aluminum must be super clean to weld on dc