After being away from MIG welding for a few years I have purchased a new Sealey 185. I have set the unit up as per the operating instructions, using Argon mix and I have the following problem - With a good earth made I press the trigger and as the wire touches the item being welded (car body) the wire splatters, if you immediately release the trigger and start again the weld is satisfactory. This happens every time you initially press the trigger but on the second press everything works perfectly. It is worth noting that the original splatter looks like the mess you get when you try to weld without the gas switched on. What am I doing wrong.