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Bubble gum, cracks & holes....s

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  • #16
    Cliffie is it possible to get someone to film you, whilst you are welding? We might pick up some things that can be done to help your technique.

    if you ask Peter, he can direct you to his DVD on welding aluminium; which made me realise that the technique is not greatly different to welding steel.

    In case anyone missed these pearls-of-wisdom from real experts on the web I post them below:

    "For aluminium (16 gauge) I would highly recommend trying either a no5 or no7 BOC style (UK) welding nozzle and, most importantly, turn the gas pressure down to 2-3 psi max (13 -20 kpa). You want a soft, fat flame. A lot of beginners make the mistake of running a too narrow flame cone, with higher than necessary flame pressure, which inputs too much heat into a thin weld zone causing burn through. Also, you have to weld aluminium at a very quick pace with oxy-acetylene. We are talking almost feet per minute as opposed to inches per minute a la steel. This is where the true art to gas welding ali comes in to form. Fast, fast, faster!

    I seldom add rod to the puddle on ali body panels - for me the rod is there literally to start the weld then finish the last 1/4" of weld.

    Also, I was taught to oscillate the torch in continuous circles to the width of approximately 1/4" - 3/8" around the weld zone as you move the torch along its path. This, apparently, was the norm during WW2 era to decrease the intensity of the heat affected zone according to my mentor. It is said to even out the h.a.z. a little, which reduces stress. This method, with good practice, should produce a lovely, flat bead with perfect penetration: A weld that needs no filing and only planishing or wheeling to make the weld virtually disappear.

    Don't get me wrong, there are many ways of gas welding aluminium, but this is what I was taught and I find it works fantastically well.

    On a side note... and this is one that's sure to raise eyebrows: I only flux the edges of the metal and not the full width of the weld bead. I find there is more than enough flux on just the edges to facilitate a perfect weld. The advantage is that flux glare is massively reduced and you have a more even temperature distribution. Again, a nugget that was passed down to me during my apprenticeship in the 1980's. "

    Regards, Matt

    "sorry for my bad english.
    recommendation from me, always clean workpieces with alcohol.
    grease on the material leads to errors.
    next Step.
    important, always clean with a stainless steel wire brush to remove the oxide. No ordinary steel brush.
    always remove oxide at short intervals.
    new oxide layer in a short time again.
    no wind or drafts during welding.
    mix flux powder with alcohol and not with water.
    you will soon see great success and aluminum with flame welding no problem.
    fact is, gas welding is the best for alloy. for my taste and experience is tig not good for thin sheet. with tig is all time cracks next to the welding lines. i have learned alu welding in england and italy to the best specialists.
    how is the same as with doctors.
    questions 10 doctors and you get 10 different advice"


    Cheers Charlie


    • #17
      Thanks for the additional copied info, Charlie. I'll add it to my cheat sheets. I had seen that before but not copied it & couldn't find the thread. I have been doing the alcohol in flux. I keep a stainless toothbrush specifically for aluminum welding and nothing else. Just got a new one because I couldn't find the one I had. Grrrrr..

      Might be able to video the welding, but things happen in a very solitary world in my shops. Hard to get any video of me cutting stone without an appointment. Rarely ever have anyone here except when I'm really behind schedule and don't have time to deal with anyone. No spare lens either, so doubt it would film very well.

      I did get some thicker pieces of scrap aluminum (5000 series) for TIG practice. I bought my Gairu from a race seat fabricator. One of his top guys who tigs full time gave me a quick TIG lesson, said it looked like I was doing well & then sent scrap home for me to practice with. Just haven't had seat time for that yet, either. I have carefully watched Peter and Jim gas welding at Will's & tried to listen to what they said, so have that in my mind as how the real Masters that I trust completely do it. Never have bought any DVDs yet. Probably should..

      Today's plans to finally weld a dolly/cart for my Gairu today so I can get it inside turned into an entire afternoon of being electrician next door at my mother's house.. Maybe another day.