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  • MatthewH219 commented on Phil B's instructable Learning to Weld2 years ago
    Learning to Weld

    GMAW and GTAW processes were both originally developed for joining aluminum. Only after the production value of GMAW was realized did it become a popular alternative to SMAW.

    HOT START is a feature developed primarily for achieving good wetting at the toe and penetration when first starting a weld. This is almost exclusively intended to eliminate cold roll on highly conductive metals like aluminum. Due to the high conductivity of aluminum, roughly twice the amount of voltage is required to initiate a weld as steel - because aluminum rapidly conducts heat away from the arc, starving the puddle for heat. Hot Start is a short boost in voltage for 0.5-2.0 seconds (average range, often adjustable), which overcomes the conductivity of the metal, resulting in a wet-in and flatter start to your weld bead, rather than a taller, cold-rolled one.It should be noted, that there are techniques which experienced welders employ to ensure a good weld start, without the benef...

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    HOT START is a feature developed primarily for achieving good wetting at the toe and penetration when first starting a weld. This is almost exclusively intended to eliminate cold roll on highly conductive metals like aluminum. Due to the high conductivity of aluminum, roughly twice the amount of voltage is required to initiate a weld as steel - because aluminum rapidly conducts heat away from the arc, starving the puddle for heat. Hot Start is a short boost in voltage for 0.5-2.0 seconds (average range, often adjustable), which overcomes the conductivity of the metal, resulting in a wet-in and flatter start to your weld bead, rather than a taller, cold-rolled one.It should be noted, that there are techniques which experienced welders employ to ensure a good weld start, without the benefit of hot start.

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