Crack Repair - (in metal that is. lol)

  1. Useless Welder Member

    OK First things first, I am a total novice at welding. I have just bought a SIP migmate 105 Turbo jobby. I have never welded anything in my life.

    Now I have recently sent my Ali/Alloy motorcycle cylinder head to various places and upon re assembling it I noticed that somebody has been kind enough to drop it and looks like give it a little kick about too.
    Anyway there is a small crack on the outside that doesnt go through, infact its a visible crack but not penetrated. I just want to seal it back up just in case it wants to get any bigger.

    I have 0.8 Ali wire, 1mm oversized tips, and some pure argon gas.

    How do I go about completing this task. The metal itself is about 5-6mm thick, with the crack being about an inch long, but I dont want to go through it. I have had a go but i dont get much actually sticking to the metal head, I get a lot of black sooty residue, and lots of blobs dropping off my tip.

    Some advise on wire speed and aps would be helpful too.

    Many thanks guys.
  2. metal_god Member

    ooooooh ally can be abit tough id make sure the surface is as clean as possible and im not sure but i dont know if your mig will be able to penetrate 5-6mm although its aluminium which is softer than steel so i dont know malcolm should be along shortly he might know
  3. Hitch

    Hitch Moderator Staff Member

    Although ally has a lower melting point than steel, you actually need more power that you would for steel.
    The other thing to consider, is dont let it arc out on the gasket faces.

    The material will need to be as clean as possible, clean it up with a sanding pad just before you weld. Also you will need to widen the crack with a grinder, so make sure it is a crack and not a deep scratch. Otherwise you will end up causing yourself problems.