vito18 wrote:And looking for all kinds of advice starting from what size work table I should make...
The bigger the better, always. But how large depends upon the size of your shop and the space available. If you're making furniture with steel tube frames, having enough surface area to clamp and fixture pieces into position while working alone is priceless. But, you can also get it done with a very small table if you don't mind the hassle of constantly re-positoing your work and swapping in your "next" pieces.
I have a 48"x72" table with clamp holes every 2" and its still not big enough often to get the entire work piece laid out and clamped. But I really don't have room for larger.
...and what welding equipment I should buy.Thinking to be welding 2,3 mm carbon steel for begining.So looking for all kinds of advice for a newbie.
The "easiest" process to learn is MIG for carbon steel. Clean the metal, position in place, pull the trigger, you're welding. The downside is: strength, bead size, and appearance.
Strength: MIG is a perfectly strong process
when done per spec. If you do enough research, and some testing, you'll discover how to setup your machine for the material and joints you're welding. But this should be done so the furniture frames don't fail.
Bead Size: MIG puts out a large amount of weld wire. You'll likely end up with a fatter, taller bead at the end. Some folks then grind this down flat(ter) and you have just removed strength. (See comment above). If the material is less than 3mm thick, you're probably getting sufficient penetration where you can remove some of the weld, but you need to keep an eye on strength over bead size.
Appearance: MIG doesn't produce those instagram "dimes" easily. So you'll end up with (proper welds) undefined "worms". If the appearance isn't a factor, then you're good to go. Also, welding inside angles, tight corners, etc with MIG is tricky, so practice makes perfect.
These are some general, rules of the road that you might consider. Other options would of course be TIG (harder to learn, but really great process) or even Oxy welding with Silicon Bronze (you just need a torch kit). This too takes some experience, but can be beautiful when done right.
Welcome, and good luck!