I just changed the wire and new bottle of gas on my Miller Matic 140. And now I am having trouble getting the weld to stick. Keep blowing through sheet metal and get a nice red ball on the end of the wire. My gas bottle is 75/25 argon co2 and the wire is .023 and made in China. Could I have the wrong wire? or maybe something on the metal? The weld wire spool does not say what it is and I threw the box away. This does not happen every time maybe 75% of the time. Been cleaning the metal same as I always have but never had this happen. Any Ideas? Thanks in advance for any help.