LOL - you need to give up and return that POS. IMHO Welding with flux core is a waste of time. It will never look good. I'd consider it if I would build a fence, but never for automotive work. The core turns into gas and that's what creates a lot of small explosions that throw the liquid metal all over the place. That's where your pebbles come from.
So, listen: Bring that thing back for a refund or store credit. Then go buy a Lincoln weld pack 100
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100039229&N=1177+90401&marketID=401&locStoreNum=8125
That welder runs on 110 nicely, comes with an instruction video and can be upgraded easily for about $150 plus a bottle from your local weld gas store. I had welded flux core with my weld pack 100 when I started with mixed results. Once I went to gas, I suddenly could weld ... For my cars I have welded anything from sheet metal to oil cooler mounts and roll bars.
George