Your heat wasn't too low just testing it out. Better to be cold than burn through, via your weld only needs to be as thick as the thinnest piece of material you're welding to, so a somewhat cold bead is fine as long as it is still penetrating. If you guys want to try something fun try virtical-up core sometime. It's satanic, I have yet to understand the physics.
Not related to your project necessarily, but another tip besides anti-splatter/anti-spatter (whichever it's called, I always thought it was the latter), try dipping your nozzle in peanut oil when it's warm, not hot, not cold, warm, and clean, then let it 'drip dry' and you won't have to clean spatter for a long time, and when you do it will fall right out. I get about 3 solid hours of welding out of one dip running .5" beads on high carbon steel, regular mig,.. before it needs my attention again.
As everyone says, if you get a bottle, you can make that so clean and pretty that you'll wish you always had it.