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Thread: cant weld aluminium for shit - advice ??

  1. #31
    Registered User MWP's Avatar
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    Quote Originally Posted by sssgtr View Post
    Minimise your cleaning cycle to the bare minimum on thin material. I found that too much cleaning was putting too much heat into the material, causing it to drop away before I could get filler near it.
    Isn't it the other way around?
    More cleaning puts heat into the tip, less cleaning puts more heat into the metal.

  2. #32
    BLING BLING PLAYA's Avatar
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    There is a lot of mis match of words going on here.

    Frequency is just how quickly it flicks polarity.

    Duty cycle really is how long you can stay welding for before machine overheats.

    Balance is % of negative vs positive or cleaning vs penetration per cycle.

    But all in all what they are saying is correct.
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  3. #33
    Problem? sssgtr's Avatar
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    I probably did have it around the wrong way, point is, don't leave it at 50% if you don't need that much cleaning action.

    I think I run somewhere on 30% with my machine.

  4. #34
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    Quote Originally Posted by PLAYA View Post
    There is a lot of mis match of words going on here.

    Frequency is just how quickly it flicks polarity. Yes, the frequency of the output power.

    Duty cycle really is how long you can stay welding for before machine overheats. That is the welder's duty cycle, yes. But in this context, it's the percentage of time the output waveform is postive or negative.

    Balance is % of negative vs positive or cleaning vs penetration per cycle. This is known as the duty cycle in all other electrical fields, it's only in specific welder speak that balance = duty cycle.

    But all in all what they are saying is correct.
    I generally run 30 to 40 % duty cycle on mine for less-than-moderate cleaning action on extruded stuff, and longer tungsten life. On thin stuff, upping it to 70% quickly heats the tungsten but avoids droop, as long as you've wirebrushed the absolute shit out of the thin aluminum. (welding light sheet end tanks on intercooler cores and 1.5mm charge piping) When working on cylinder heads, if it's a clean casting I can usually work around 50%, but if it's old, oily, and greasy, I'll still have to do a "de-grease" pass by running very high duty cycle, then re-grind the tungsten (it picks up all the shit that comes out of the aluminum-so get used to re-grinding it often for very oxidized or dirty aluminum.) and run a very low duty cycle pass to put a LOT of heat into that area of the casting, which brings up even more crap. Another high duty cycle pass to rip all the crap out of the weld area, re-point the tungsten again and then back to 50% for doing a clean-ish casting.

  5. #35
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    Just from the first post, it sounds like you're running on DC neg, or have your AC balance heavily that way. The biggest problem with AC balance is that different manufacturers label their welders differently, hence one of the guys above say about 70% works good, another says 30% does. They will actually both be at the same point, just one has a machine that displays positive balance and the other, negative balance (or they could be using the same machine but one of them has his welding leads hooked up the opposite way). Some manufactures will even display a zero in a central location, with plus and minus numbers either side of it. In this case the "zero" generally around 70% actual balance.

    Anyway, just as a test, set your AC balance to 70% and try and run a bead on some scrap plate. If you have the same issue, swap your leads on the machine and try again. It might weld good or it might melt the tungsten away (both indicate incorrect AC balance being the problem), or it might do the same thing, or it might do something completely different, indicating a material issue or a combination of both.

  6. #36
    Gas Turbine enthusiast da9jeff's Avatar
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    Quote Originally Posted by Xnke View Post
    I generally run 30 to 40 % duty cycle on mine for less-than-moderate cleaning action on extruded stuff, and longer tungsten life. On thin stuff, upping it to 70% quickly heats the tungsten but avoids droop, as long as you've wirebrushed the absolute shit out of the thin aluminum. (welding light sheet end tanks on intercooler cores and 1.5mm charge piping) When working on cylinder heads, if it's a clean casting I can usually work around 50%, but if it's old, oily, and greasy, I'll still have to do a "de-grease" pass by running very high duty cycle, then re-grind the tungsten (it picks up all the shit that comes out of the aluminum-so get used to re-grinding it often for very oxidized or dirty aluminum.) and run a very low duty cycle pass to put a LOT of heat into that area of the casting, which brings up even more crap. Another high duty cycle pass to rip all the crap out of the weld area, re-point the tungsten again and then back to 50% for doing a clean-ish casting.
    You've just confused everyone in this thread.

    In welder land duty cycle is how long you can weld vs off time ie 30% on = 70% off before it overheats/trips a thermal switch.

    Balance is the % time the output is electrode negative vs electrode positive.

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  7. #37
    Registered User MWP's Avatar
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    "Duty cycle" can be confusing because to electrical/electronics guys it means something different.
    To us duty cycle is % on time for pwm... which funnily enough is exactly what "balance" is in tig welding.
    But yeah, this is about welding, need to stick to the welding meanings of the words.

  8. #38
    Problem? sssgtr's Avatar
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    I was referring to percentage output in AC vs DC in my post/s - "amount" of cleaning action.

    As already stated, wirebrush and acetone clean reduces heat required for cleaning - try and just see what works for yourself.

  9. #39
    BLING BLING PLAYA's Avatar
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    I think what we should do to make it real easy for everyone is we will use the word duty cycle for how long your machine can operate, balance, and also pulse.
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  10. #40
    Gas Turbine enthusiast da9jeff's Avatar
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    Quote Originally Posted by sssgtr View Post
    I was referring to percentage output in AC vs DC in my post/s - "amount" of cleaning action.

    As already stated, wirebrush and acetone clean reduces heat required for cleaning - try and just see what works for yourself.
    This is still wrong lol. Ac means that it switches between electrode negative and electrode positive. It doesn't switch between ac and dc.

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  11. #41
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    Hahahahaha, fml. Glad you knew what I meant to say!

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