First, let me start by saying I am not a welder and have gained new respect for the field since I have been given the responsibility of resolving this problem.
I have a Miller shop master welder. It has a spot weld setting with adjustable spot time, wire feed rate, burn back, amperage, etc.
I am welding a piece of stainless steel hinge to a 1/4" thick piece of aluminum. it is a 6061 or 6063 grade alum. The hinge has a .125 hole in it. I keep having problems with inconsistent welds. a majority of time time I get a big build up on the front side with a lot of splatter and adhesion to the nozzle but no penetration through the back side. I can pull it apart very easily Then some times it will blow a hole right through without changing a setting. I have suspended the feed cable from the machine to the gun from the ceiling to ensure a good consistent feed path. Occasionally it will weld perfectly with a nice pretty puddle on the front and a tiny nipple on the back side and I can't pull it apart. I have tried adjusting all the settings and had a repair tech out several times. When he left the first day it was working ok and then it went back to incosistency without changing any settings. I read on another thread that it could be because I am using 75/25 argon nitrogen mix and I should try using pure argon. can anyone offer any advice?