questions about welding with FLUX wire

I have an old National Welders 110v mig welder that works good.  I have a very basic knowledge of welding but still need more practice. I only use it for light welding like floor pans.

 I am running what looks to be copper bare wire now but ran out of shielding gas.  I am thinking about switching to FLUX wire and eliminate using gas.  

What are the draw backs of flux v. gas if any?

Do I need a tip specific for FLUX or will my existing tip work?

What is the best size FLUX?

How do I determine heat setting?

How do I determine wire speed.

The biggest drawback with flux cored wire is the mess from the flux. Flux core also works better when the polarity is revesed.

As for the tip, it depends on what size of wire you're running now. 0.035 is a common size of flux cored, your solid copper coated steel wire is likely smaller.

The two biggest advantages of flux cored are the ability to weld outside on windy days, and the materials you're welding don't have to be as clean, even though you'll get better welds when they are ground clean and not just wire-brushed.

As to heat and speed, a lot a variables at play there, welder amperage, metal thicknesses, and so on. You'll just have to experiment.

i agree with don... and i want to high lite the switching of the wires leads.

I started welding a few years ago, so I am not the most accomplished or knowledgeable welder. I find working with gas infinitely easier than working with flux core wire.

I also found that a high quality hood, made a huge difference in what I could see when welding. I still have some trouble seeing the line I want to weld sometimes and have to remind myself to put more lights up around the work or adjust the brightness on my hood.

You have to be able to see the weld puddle clearly and what you are trying to weld. With gas that is fairly easy to do. With Flux core I had a much harder time.

Patience is necessary to minimize grinding and avoid metal warpage. Move around, take your time. Set up on scrap metal is a must if you want to learn the proper settings. One of my good friends has been a welder for 20+ years and he still adjusts on scrap whenever working with anything different-shortcuts are not your friend.

Best answer I can give you is to just stay away from flux core. I have been welding for a lot of years and even if I run out of gas, I just quit and wait till I can get some gas filled. Flux is a mess to deal with, not nearly as nice of welds. Just my opinion but I would not use flux core.

Do places like Northern Tool and Tractor supply sale full tanks?

What do I ask for, just shielding gas?

Yes, Tractor Supply has it.

Its usually a mix of Argon, Carbon dioxide and Oxygen. There are different mixtures for different types of metals, but I think this is the most common.