Shaun,

I'm guessing that you're overdoing it. It's doubtful your main circuit has enough power to handle all of that. Ovens are generally very high draw. A compressor and welder might not be a problem - depending on the rating of your main box.

Like some of the car questions, it's impossible to provide much help without data, like:

- recommended breaker size for welder, compressor and ovens.
- size of your current box (100 amps?)
- how much of your box is in use now, and do you have an electric clothes dryer, electric oven, electric water heater?

Even if you put in another breaker box, you may not have enough power in the service to handle all you want, and running a whole new service from the street is muy expensive.

I wish I could help on cost, but I was capable of doing my own, so I don't know.