That is a VERY interesting setup Tp1.
The MIG sounds like it needs a new tip on the handpiece, or at least run an oxy torch cleaner through it to get the crud out.
Are you running the flux cored wire on DCEN
(Direct current electrode negative) This is very important, otherwise the wire vaporizes without any penetration.
Your tip problem Wayne, is as the wire heats up and expands, it jambs. It cools off and seems ok. It frustrates the hell out of you. Give it a really good clean or replace it.
With gasless welding, a clean tip is more important as there is no gas to cool it.
To make it even harder, when it jambs, the feed roller spins on the flux cored wire and damages that contact point of the wire. Particularly when the feed roller has been wound down to push it through.
When this damaged bit gets to the torch tip, it won't feed through easily.
I bet if the tip is cleaned well and there is no rust or damaged bits on your wire, you will have to decrease your wire speed.
Wire speed on flux cored, is slightly more critical due to the reduced mass of steel in the wire to achieve the same results.
A lot of the cheaper "flux cored" wires are not multiple pass. So the welds must be chipped, or wire brushed before welding over them.
Pop the welder on a close table, so you can adjust the wire feed while you are actually welding and see (or more importantly hear, a nice even crackle) the difference.
Hope this helps mate.
I am going to buy another one tomorrow to finish it
)a control using a form of curved traveller
