Fender, you have a bunch of 'issues' going on there.
First off, as mentioned (multiple times), run some 0.030 diameter solid wire for most work with that size/class machine. If working on sheetmetal, then use 0.023/0.025 wire.
Next, although you did grind a bevel edge on your workpiece, your fit-up gap is waaaay to big. You are attempting to 'weld' air there bud!
The reason for a gap and the bevel edge prep when fitting up for a weld is to allow physical access for the electrode and the arc to 'reach' down into the bottom of the crevice between the two edges of the workpieces and
help the operator get more complete weld penetration/fusion.
But your excessively wide gap there on that thickness of workpiece just means you have to bridge your weld puddle across that air gap and also fill in that air gap with metal from the weld puddle (which all has to come from the melting electrode wire you are using).
Your two tack welds with that much air gap just barely melted into the edges of the workpieces and left a rather 'cold' puddle trying to bridge across the (excessive) gap which then just dripped right through the air gap and landed on the 'cold' concrete floor. Barely adequate for a tack weld and it's not all that surprising (to me) that you could rather easily break the two pieces apart by hand as the only actual fusion into the workpieces was at the thin feather edges of the workpieces.
A 140-amp 120V class machine can (usually) make adequate welds on 1/8" thick workpieces with solid 0.030" wire and C25 shielding gas. Although IMNSHO, that thickness is kind of pushing the upper limits for those machines with solid wire. 16 or 14 gauge workpieces, easily, but going up to 1/8" thick is a bit much with the 120V machines and solid wire.
Run those 120V machines with some 0.035 dia NR211-MP FCAW-S wire and you can blow right through a 1/8" thick workpiece if you don't pay attention and/or have the welding parameters set right.
As an exercise, take two pieces of your 1/8" thick angle iron (bed frame) and remove the mill scale and paint off of some of the surface. Lay one piece on top of the other piece at a 90 deg angle and clamp them together. You will then do a lap weld of the top piece onto the bottom piece, running the weld puddle (watch the actual weld puddle of molten metal and not the bright welding arc!) right along the edge of the top workpiece and watching the puddle melt that top edge and melt
into the bottom workpiece at the same time.
Practice that for a while before trying to weld an excessively gapped **** joint.
With that wide air gap between the two workpieces and basically 'dripping' some molten steel onto your concrete floor you have poor crappy 'hot melt' action going on instead of solid well-fused welds joining the workpieces together.
