It could make a lot of difference, or none, depending on circumstances.
Need more info-

What Code / Spec are you working with?
What position are you welding in?
What process are you welding with?
Do you have toughness restrictions?

Tim

Hello Harman, the better question would be are there any considerations/requirements for heat input, or it's control, and whether anything detrimental will result from your choice. Joint position could also be an issue, in some instances a 1/2" fillet in one pass could result in undercut along one of the toes and fusion issues along the other toe. Possibly provide some additional information and you'll likely receive more specific and better responses. Good luck and best regards, Allan

I strongly suggest you attempt the 1/2" fillet as both a single pass and multipass and let the "proof" be in the finished weld.

So many variables can affect the quality of a weld that size so record exactly what you are doing for each attempt.

Love to see your results.
Gerald

As the others have mentioned.. There are some factors.

Nevertheless, that is a very big single pass fillet...  Doing trials is a good idea... But do fillet breaks to make sure you are getting what you think..  A visual is not good enough to judge.

Fillets that large are possible in the Flat position... once the fillet goes horizontal, gravity complicates things as described above, with undercut and overlap as well as fusion issues.

Can it be done on a bench during trials ?      sure.

Can it be done with consistency with every welder's differing skill level, various fit-ups, various amounts of mill scale?,  around corners and end returns?

What will the weld terminations look like...??? With the .052 wire I suspect you will be running in excess of 360 ipm and 320 amps.  This means you will most likely have molten weld pool exposed to oxygen on the trailing edge of your weld pool causing oxidation on the weld face.  You will likely have a very large weld pool indeed, and when the weld terminates the pool will freeze from the outside-in, causing a piping pore in the center, which under a 10X inspection likely will show cracks... This type of termination defect will increase as gun angles increase beyond 15 degrees push and the puddle becomes tear drop shaped rather than round.

Lastly.... Don't let the welders trick you with "tribal knowledge"    Your .052 filler at 340-360 ipm will produce 260-290 amps and a deposition rate of about 12.5 - 13 lbs. an hour..   This 13 pounds of hour will be the rate whether you run a single pass or multiple passes.   It is not faster to run a single pass..... The guns squirts what it squirts, whether its a stringer or a fat, whipped blob of a pass.  If the arc-on time is the same, the deposition of weld metal is the same. Keeping the current at 260-280 amps will keep the weld pool small enough to reduce the termination defects mentioned above and still give enough current to do 10ga to 10ga fillets with no burn thru, all the way up to unlimited CJP joints. 

There is a temptation to run at higher WFS because the .052 can take it as a heavier conductor...  The only time I would recommend this is if you arrange your end consumables in such a way that your contact tip is recessed 1/4" inside your nozzle.  This can provide a boost in deposition whilst keeping the current a bit lower.

I would really give some thought to such a large fillet size before you green light it on the shop floor.

From a man who has fought this very battle  :)