Getting porosity by using Flux Core Gasless welding wire

Q: I bought flux core wire from you people a while back and I have been getting porosity from your flux core wire. Can you explain why?
Answer from WeldingCity: The gasless MIG welding such as E71T-11and E71T-GS results can be affected by more factors than traditional solid wire welding like ER70S-6, such as welding parameters, surface conditions, plate thickness, machine set-up, work conditions and operations. Enclosed please find the welding parameters suggested from the manufacturer. You may use them as reference and let us know if there is any question. We will forward them to manufacture for further investigation. Also the below customer comment is for a Lincoln Inner shield product which supposedly is one of the best gasless MIG welding wire products in the world. Hopefully it will help.

Answer from Manufacture: You are quite right. You use different wires. You also need a different polarity setting on the machine to run gasless flux-cored wire, so this can’t be run on a standard gas only mig. (you need the Dual-Purpose ‘EN’ models). In practice you will find that the standard gas set-up runs much better, especially on thin stuff. It welds a lot smoother & cleaner than the flux-cored wire which tends to burn holes in thin car panels.
A dual purpose machine is handy if you suddenly run out of gas in the middle of a job but you will find that you will be using it in gas mode most of the time on car panels. The Clarke machines are also a good choice out of the hobby MIGs.