If your weld looked like bird droppings you're probably doing it too slow (and have the amperage too high).
Keep practicing, change the variables and you'll soon get the hang of the settings. Like Fergal said - it should sound like you're frying bacon. Usually welders come with a chart on the...
I don't know your budget but you can get a decent MIG welder for around £100. Not the cheapest chinese made ones either, just a low amperage one from a reliable manufacturer. This is worth the investment as they last a number of years and usually have a decent warranty. Well worth the investment...