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Old 09-07-2011, 05:32 PM
oldred oldred is offline
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Originally Posted by gow589
What I see is a lot of people who weld professionally say you cannot weld thick metal with a 110v welder; I say they never had to.

I have welded professionally from 1968 until I retired a few years ago and when I hear someone, especially a pro, say that a 110 welder can't be used on thick metal the first thing I think is "that's BS"! While there may be limits from a practical standpoint due to duty cycle, time spent doing the job, etc there really is no limit to how heavy a section that can be welded with .024 wire and a 110 machine. The trick is pre-heat! With small wire and low AMPs there can be serious problems when starting the weld on a heavy section because the thick metal will sink off the heat too fast and cause chilling of the bead leading to under-bead cracking from thermal shock, poor penatration and a brittle weld. That's where the mistaken belief these machines can't be used for heavier metal comes from but this is very simple to avoid. Just heat the area to around 400 deg or so, just too hot to touch with your bare hand, and then there is no problem. The inherent heat from the weld will eventually raise the temperature if no pre-heat is used but a lot of damage could occur before the metal becomes hot enough, the pre-heat will prevent this. An Oxy/Acetylene torch is useful for pre-heat but unless the part is really large even a small Propane torch is all that is necessary, 400 to 450 deg is plenty for starting the weld and that's a long way from red hot so those little torches are usually enough. In any case the pre-heating makes a world of difference when using low AMPs and small wire.
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