I don't think you will find a home/garage welder that can make a birds nest. But if you do, that's a decent feeder.

Please analyze my welds, if they are not "good" yet. This is Lincoln 100 without gas (if it matters), and Lincoln innershield flux wire 0.035.
While welding them, I can see that the high temp setting penetrates the re-bar deeper. With the smaller rebar (maybe half size the one on the pics) it almost went through the bar if I point at one spot for too long

At mid temp setting
http://i100.photobucket.com/albums/m...ps0p59yuid.jpg

At high temp setting
http://i100.photobucket.com/albums/m...pszluv2fpp.jpg

It may be just me, or the pic. But it doesn't look like you got a puddle going in either pic. Try varying the wire speed with the highest heat setting. You'll know you have it right when the metal glows red hot and you have a very bright puddle. Welding is managing the puddle. If you don't have enough heat, then you'll have to heat the joint with a torch first, using Roxy-acelylene.

Try different metal samples too. Some types of metal just doesn't weld with some types of wire.

Get a gas valve and run CO2. Lots of spatter, but good penetration, which you need with a small home machine.

It's hard to get good looking welds with flux-core.

(not a pro so could be totally wrong here but)
To me the mid-temp looks prettier.
But it should be slowed down for more penetration.
Also have an initial fill layer of the gap (fast and hot/back and forth to fill).
That's what I would instinctively do with my 110V Lincoln 135 gas at least. Could be totally wrong.
Without the gas to blow the crap away and shield the cooling, the slag from flux-core just builds up and causes complications. Techniques may be different.

thanks guys.

Rusnak,
On this bar, I was trying to increase wire speed to get lot of weld (puddle) but a tat higher wire speed, will make it pop.

I also tried smaller bar (you can see the smaller bar behind in one of the pics). Maybe the smaller bar is softer material, for the same setting, that smaller bar melted quicker and created puddle. Also, it's easy to burn through it.

To prevent burn through aim your torch into the rebar 90% of the time and weave onto the thinner tube 10%, or thereabouts...

Your welds look like a series of decent tack welds, you need more energy in the weld to get a molten puddle.

The way to test your welds is to break some, a good weld will pull parent material....

Yes you can. Get a strip of explosive bonded or roll bonded iron/aluminum. Weld the iron side to iron and the aluminum side to aluminum. Good to go.