before you take it back, try turning up the wire speed, around 5-6. What this will do is turn down the heat. I bought the following dual mig welder (flux or gas, currently using flux, I have another bigger welder for gas) from harbor freight and was burning through the metal quite alot and this was on wire speed 1. I turned the speed up to 5-6 and loosened the wire tension wheel slightly and that fixed it.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94164I have had very good luck with this welder, I had it for about 7 months, and so far no problems and Ive used it constantly.
Now if you do end up taking the 90amp welder back to hf. Before you go out and buy another welder (whatever make/model), check your local classifieds, you may find a really good deal on a hardly used welder, especially with the economy like this, some shops may have closed and need to get rid of their equipment.
