what is the alloy Im guessing carbon by the rods you are useing, use 3/32 if you have it and how much medal are you trying to carry, run tight small stringers and if you are welding the tubing together with a open butt then make it a realy tight fit 1/8 tubing is realy unforgiving when it gets to hot if you have the capability of TIG welding then that would be best but try 3/32 if you can get some. oh yea are the arc as close to the puddle as possible sounds like you are long arcing on the tubing also remember longer the arc the hotter it gets and your stinger should be on possitive and ground on negitive.

maybe use a 3/32 and move a little faster.i would try to use some 6013 or maybe rev polarity.hope this will help you.

Try 3/32" rod. Use around 75-90 amps for 7018, 55-65 for 6010. This is only a baseline, you may run a little hotter or colder. 3/32" is perfect for lite gauge material. You can always wire weld it with your 22A if that isn't working. That should do it though. When you're welding with 6010, use a slight whipping motion in & out of the puddle. That will control the heat a little better. Good luck! Steve.

Try welding the verticals downhill with the 6010. Flat and overhead (if necessary) turn heat back enough to join the two pieces of metal; you can pause and whip with the 6010. pause can be for one second or five seconds if it takes that long to cool down. That thin of metal doesn't have alot of heat sink capability. You may need to skip around to allow the steel to cool.

Weld it good enough to where you feel confident that it will hold whatever you put on it.
Add additional bracing as necessary.

Most common; is to hook your stinger up to the positive for reverse polarity. You will get less penetration if you hook it up opposite of that.

3/32 is a better size and 6011 is another option, less penetrating than the 6010.

Anthony,
I was just welding some of the same material today, but I was (MIG) welding it and yes that 1/8" square tube can be very unforgiving if given too much heat. I am by no means a master welder, but  since you probably won't be placing a ton of weight on your table...I would try using a 3/32 6013 rod and run it at about 45 on the heat DCEN. it's a contact rod so you don't neccessarily have to hold a gap, just strick an arc and move. If you still have problems with it blowing through at that point, I would also suggest that you try cutting some strips of thin flat stock to tack to the inside wall of the tube and then fit the joining tube over the tacked -in strips. This will give some heat sink to the square tube and act as backing to allow good penetration and avoid blowing through. I don't remember seeing this approach suggested in the thread. It has worked for me in other situations similar to what you are doing. i hope this helps you out.
respectfully, Jeffrey

PS. Jeff Parker made a good point about long arcing. it will really heat up the steel and cause you to over heat and burn through. That's why i suggest using a contact rod E6013 it runs cooler.