Tig welding aluminum

Discussion in 'Castings, finishing/ repair/ and patina's' started by Zapins, Sep 5, 2018.

  1. DavidF

    DavidF Administrator Staff Member Banner Member

    I cant think of any reason why it would not. Typically injection molder screws are SS but thats likely only due to corrosion resistance...
     
  2. Frank Clark

    Frank Clark Copper

    OK, so this is a month old thread, but I TIG weld AL all the time so I'll chime in.

    I have a Miller Dynasty 200. For large castings, it takes a long time to get the puddle going. Once you get the whole piece hot (say 200-250 degrees), welding on it is MUCH easier. For any large parts, I crank it up to 200amps and start out foot to the floor. I will have to back off when the casting gets hot. I do wish I had a bigger welder.

    Pre-heating your casting would be a big help. I use heaters like: https://www.heatandweld.com/index.cfm/product/102_81/cmh18-80-ceramic-mat-heater.cfm
    and run them off a variable output SCR. Those folks will make any voltage you want, but the higher the voltage the larger the heater. You can run an 80V one off 115 using an SCR to dial it down. You MUST control the power delivery on these as they will run up to 2000F+ if you don't. The cheapo temperature controllers are fine, but don't use the cheapo SCRs and don't leave it unattended (SCRs can fail closed). Throw the heater on your welding table, casting on top of it, insulation over the lot and warm it up. I'm sure you can find other ways to pre-heat. I'm just using parts we use at work so I have easy access and know them well.

    For filler rod, I strongly recommend Hobart MaxalTIG R4943. It's not cheap (I think they have a patent on it). But it is much better than anything else I've used. It's also heat treatable so if you are repairing a casting before heat treating, your repair will end up similar to the casting.

    On your CT electrical issues. I'm from Texas, we just do it ourselves and skip getting the government involved. My garage is wired for 220 to Mill, Lathe, Welder and A/C. Outside I have 50A/220 service for my Kiln and Furnace. Did have a commercial electrician that works for me give it all the once over to make sure it is correct and up to code.
     
  3. Jason

    Jason Silver Banner Member

    Hey Frank.. Jody says running a helium mix helps with thicker stuff. Ever try that?
     
  4. Frank Clark

    Frank Clark Copper

    No, but I've heard that. Also have heard of folks using a mix with a small percentage of Hydrogen. I think I'll leave that all to the pros!

    I would like to be able to build my own AL chassis down the road. For that I will have to upgrade my welder (and get a water cooled torch). Will go that route before changing gasses. Patience or pre-heat get's be by for now.
     

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