TIG MIG Overlap - Porosity

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I'm not a welder but found myself on a team with some very experienced highly skilled welders trying to reduce weld porosity.  Just wanted a little education.  Parts are MIG welded in hard to reach/see areas from a couple different angles, then the MIG beads are joined together with TIG.  Most porosity occurs at the bead ends and overlaps.  Interested in any suggestions...
Reply:Lack of pre and post flow on the mig welds maybe. Can you explain a little more in depth what exactly you are doing?
Reply:Its usually gas coverage.  Especially if you are at odd angles with the gun.David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by LewisI'm not a welder but found myself on a team with some very experienced highly skilled welders trying to reduce weld porosity.  Just wanted a little education.  Parts are MIG welded in hard to reach/see areas from a couple different angles, then the MIG beads are joined together with TIG.  Most porosity occurs at the bead ends and overlaps.  Interested in any suggestions...
Reply:All of these scenarios are true with what we are doing.  Thanks for the help - I'll take these ideas back to the team.
Reply:Grinding the stops and starts. This was ground into my head day after day. In most processes the starts and stops will have some amount of non-fusion.
Reply:if its in the starts and stop use run off tabs. this will totally eliminate your stops and starts within the joint.