Welding Tips and Tricks

hey
ive got a 115V mig welder . the duty cycle is 20%.
i understand that means 2 minutes out of 10 is the supposed max i should be welding with it.

its an older model. a rebadged Miller, Auto-Arc, that does NOT have a warning light or any indicator if i go over the time period.
actually, either its duty cycle is a little higher than marked or im pushing it too hard... i think.
because it feels like im welding more than two min at a time with it and all seems ok. it doesnt seem to have any ill affects.

guess i could set a clock or timer somewhere close. although that would be a PITA
maybe what seems like "over two minutes" is actually 30 seconds and im just way off in my estimates, but i still would like to know...

-how strictly should one follow the suggested duty cycle?
-how do i know if im harming the welder by going passed the rated duty cycle?
-what are the most common manifestations/symptoms of a welder that is pushed too far over its duty cycle?

thanks
WW

That 20% is most likely at maximum current - so if your not wound right up it will be higher - the makers will usually make this test in a worst case scenario of 40 degree C @90 % RH ambient conditions - so mostly you will get better results especially in the winter & that is 2 minutes in every 10 so also takes into account heat soak between cycles - when you start from cold or leave longer between runs this also helps - even though there is no warning light I'd be shocked if there is'nt a thermal trip on the main transformer - so it will cut out automatically - it just does'nt tell you - if unsure take the tin cover off the machine & have a look to confirm this - if you find one just weld till it trips if you have to - but obviously don't run the machine hotter than you need to if you plan your weld / prep time to suit - even machines with internal fans will cool better if you place an old desk fan or similar blowing air at it - every little helps.

right on noddybrian.
thanks much

Winston, I know this is a two month old post now, but I gotta ask. What are you welding on that requires you to go for a solid straight two minutes?

Virtually nobody but a pipe welder with a stick machine, can keep in one position for more than two minutes at a time, without body shifting and taking a pause/break between welds. With mig welders, one is usually shifting around and repositioning constantly.

Just curious what you're making on a regular basis for two minutes at a time.